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Optimization models are developed for simultaneously determining the pipe layout and the pipe design for storm sewer systems. The pipe design process includes computation of commercial diameters, slopes, and crown elevations for the storm sewer pipes. The optimization models aim to minimize the total costs of the layout and the pipe design for most of system elements. The optimization models are formulated as a 0–1 Integer Nonlinear Programming problem and solved using the General Algebraic Modeling System without the use of heuristic models which were characteristic of all previous models for the simultaneous determine of the pipe layout and pipe design of sewer networks. The models are based upon two different optimization approaches: (1) considers one or more commercial diameters of pipe connecting two manholes and (2) considers only one commercial diameter in a pipe connecting two manholes. The commercial diameters, pipe slopes, crown elevations, and total costs of the storm sewer system were compared for the two approaches using an example that illustrates the savings in cost by allowing multiple pipe sizes. The two new optimization modeling approaches developed herein can simultaneously determine the minimum cost pipe design (commercial diameters, slopes, and crown elevations) and pipe layout of storm sewer systems and satisfy all design constraints.

This paper presents a parametric analysis of the outward flow reaction type turbine known as a Z-Blade turbine for low-head low-flow conditions. By applying the principles of mass conservation, momentum and energy, a nomogram was designed to investigate the theoretical performance characteristics. Based on the parametric analysis and the governing equations and experimental results, attempts have been made to prove that the mass flow rate, angular speed, centrifugal head, power output and efficiency respond dynamically to the water head, radius of the rotor, size of the PVC pipes and the nozzle exit area. A turbine with a 1” pipe diameter gives a higher performance compared to a 1/2” pipe diameter, and certainly the performances of both pipe sizes are improved when the supplied potential energy is increased. This innovative turbine has a maximum rotational speed at an optimum turbine diameter at 0.6m, accompanied by a point where there is a sudden reduction in the water flow rate, where previously the increment in the water flow rate was very high. This can shows from the outcome nomogram with 1” pipe diameter can perform 350 rpm speed with 1.48 L/sec water flow. The Z-Blade turbine has been examined and has shown good potential to be used for low-head (3m, 4m and 5m) and low-flow (less than 2.5 L/sec) conditions.

The design of wastewater system pipe size is traditionally based on the maximum wastewater flow that is a function of multiple factors. Understanding the appropriate peaking factors (PF) by using daily flow variations through wastewater collection systems (WWCS) is essential for cost-effective design. This paper describes the maximum and minimum PFs by using wastewater flow data of four separate residential areas such as Lara, Belek-1, Kemer, and Hurma in Antalya, which is the tourism capital of Turkey. The study involves the analysis of wastewater data recorded at daily interval for two different time periods (2006-2009 and 2016-2019) in Antalya. There is a comprehensive investigation regarding PFs that involves sustained peaking flow and percentiles. Therefore, a new empirical equation was proposed by using wastewater flowrate for the estimation of the maximum daily peaking factor. When the daily PFs are determined in the range of 1.31-1.52, 1.60-2.58, 2.26-3.29, and 1.93-2.29 for Lara, Belek-1, Kemer, and Hurma wastewater treatment plants (WWTPs) for 2016-2019 time period, they are in the range of 2.19-2.93 and 1.95-3.31 for Lara and Hurma WWTPs for the time period of 2006-2009, respectively. In brief, this study presents a comprehensive calculation of PFs with a determination of their sustained flow analysis with different durations and percentiles. PRACTITIONER POINTS: This study presents the findings regarding peaking factors and its statistical analysis for different time periods. Statistical analysis included sustained flow, and the percentile of peaking factors was applied to waste water flow data for touristic city of Antalya. The new formula of PFmax,dry=39.18⋅(Qav,d)-0.32 was determined by using more touristic areas of Antalya within the scope of estimation of the daily peaking factor for dry weather flow by using average daily wastewater flowrate data with the determination coefficient of 0.95.

A new methodology has been developed for analyzing heat and mass transfer to predict wax deposition in crude oil pipelines using the law of the wall dimensionless parameters. A set of physically meaningful dimensionless groups and parameters has laid a strong foundation behind the proposed methodology. The paper presents a discussion regarding the development of scale-up correlations from laboratory scale to field scale, considering the combination of both analytical groups and empirical correlations. Data from previous literature studies were employed for determining realistic values for the developed parameters and scale-up correlations. The utilization of new dimensionless scale-up parameters indicated that the wax deposition in crude oil pipelines is independent of the Reynolds number and the inner diameter of the pipeline. It further indicates that wax deposition in crude oil pipelines is mainly dependent on the heat transfer process and not on the shear reduction process. The dimensionless technique developed here can be utilized for determining the optimum pipe size and pigging frequencies to reduce and mitigate the effect of the wax deposition process.

Through experiments in a straight Plexiglass flume, the scour control performance of a spoiler installed under a submerged pipe laid on the river bed was studied. The experiments were carried out with four different pipe sizes, four variable flow rates, and four spoiler widths under clear-water conditions. The results were suggestive of the efficiency of the attached spoiler in reducing the length but increasing the depth of scour. On average, the incorporation of the spoiler shrunk the scour under the pipe by 21% in length while making it approximately 22% deeper. Furthermore, with both the pipe and the spoiler under it, the maximum increase in the scour depth 55% was obtained with a relative width of 0.26 and a pipe diameter of 4.8 cm at Fr = 0.42. The statistical software package SPSS was employed to formulate Equations Was obtained based on a linear regression between the maximum scour depth and length.

The water distribution network (WDN) design comprises determining optimal pipe sizes to achieve minimum cost pipe network to meet the required demands and performance levels. However, with time, the water demand for any region changes due to population, migration, and lifestyles, so interventions need to be made to the existing WDNs. Therefore, the capacity expansion problem consists of determining the suitable interventions at various stages such that the required demands are met at minimum cost. The present study proposed a novel methodology for planning such interventions based on Dynamic Programming (DP) formulation and presented a combined Self-Adaptive Differential Evolution and DP (SADE-DP) methodology for solving the WDN expansion problems considering life cycle costs. The methodology is applied and tested on three benchmark WDNs, namely New York Tunnel (NYT), Two loop (TL), and Blacksburg (BLA) networks, and also for a real case study of the Badlapur WDN in Maharashtra, India. The proposed model solutions are validated by comparing them with other WDN expansion methods taken from the literature. The results indicate that the proposed SADE-DP approach is computationally efficient and provides cost-effective solutions by meeting desired performance levels at various stages, and can serve as a potential alternative for solving real-world WDN expansion problems.

Biopore Infiltration Hole (LRB) is an alternative and simple technology for rainwater infiltration that can be useful as a processor for organic waste from households and can be applied in narrow urban residential areas such as in Kota Bambu Selatan (KBS) Sub-district. LRB technology in general is to reduce water inundation, increase groundwater reserves, and reduce the volume of organic waste. Therefore, the Community Service Program of the Environmental Engineering Study Program has the aim of providing counseling and training to PPSU officers (Public Facilities and Infrastructure Handling Workers) of KBS Sub-district in implementing LRB in accordance with technical requirements without impacting groundwater pollution. The method used was to provide LRB educational materials aimed at the community, especially PPSU officers through direct explanations, educational posters and brochures. The current condition is that KBS Sub-district already has LRB at several points in 2017, however it got some technical problems such as pipe size is too small, namely 7.5 cm (minimum pipe diameter requirement is 10 cm); there is dredging activity, there is no top cover so that small animals often enter, and in some locations there is often stagnant water.

The insulation thickness (IT) of double pipes buried in the soil (DPBIS) for district heating (DH) systems was optimized to minimize the annual total cost of DPBIS for DH systems. An optimization model to obtain the optimum insulation thickness (OIT) and minimum annual total cost (MATC) of DPBIS for DH systems was established. The zero point theorem and fsolve function were used to solve the optimization model. Three types of heat sources, four operating strategies, three kinds of insulation materials, seven nominal pipe size (NPS) values, and three buried depth (BD) values were considered in the calculation of the OIT and MATC of DPBIS for DH systems, respectively. The optimization results for the above factors were compared. The results show that the OIT and MATC of DPBIS for DH systems can be obtained by using the optimization model. Sensitivity analysis was conducted to investigate the impact of some economic parameters, i.e., unit heating cost, insulation material price, interest rate, and insulation material lifetime, on optimization results. It is found out that the impact of sensitivity factors on the OIT and MATC of DPBIS for DH systems is different.

Statistically, access to proper sanitation in Muara Enim Regency reaches 90.75% in 2018, but it needs to be ascertained whether it is safe in the context of no latrine leak that can pollute the environment, especially in areas with the lowest level of population welfare. Muara Lawai village is the village that has the highest number of poor and near poor people and villages with status as underdevelop village in Muara Enim District. Based on an analysis of existing conditions, the facilities for wastewater sanitation infrastructure used by low-income communities (MBR) and non-MBR in Muara Lawai Village were found to be still not feasible and safe. Efforts to provide adequate and safe sanitation infrastructure that can be implemented in Muara Lawai Village are a off-site domestic settlement wastewater system with initial service coverage for 41 households or 205 people. total wastewater generation (Q r ) 16.40 m 3 / day with peak discharge (Q peak ) of 54.82 m 3 / day, minimum discharge (Q min ) 2.33 m 3 / day and infiltration discharge (Q inf ) 12.96 m 3 / day, so the design discharge is obtained at 67.78 m 3 / day. Calculation results in the service sub-system required a special PVC waste pipe with a roughness value (manning) of 0.012 with details of house connections pipe size 4"along 212.1 m, service pipe size 6" along 178.8 m and main pipe size 8"along 220.7 m. The need for control tubs is 31 units installed at each pipe meeting with a size of 50 x 50 x 50 cm. In the processing sub-system (WWTP building), the processing technology used is anaerobic biofilter with the overall dimensions of the WWTP building of 7.5 x 2.0 x 2.5 m.

One of the most important roles of water system supply is piping networking. Performance of water supply sistem service is determined not only by a capacity from the source, but also by water volume which must also be up to the vertices with high flow and adequate pressure as needed. Besides, the effectiveness of a pipline is measured from the cost of investment and operational cost over life of specified order. In order to achieve adequate pressure and flow conditions it must be analyzed the size carefully. Linear programming represents the completion of operations research techniques that can solve optimization problems. Linear prograsmming is used to minimize cost size of pipe. On this research, a sample informartion taken by a clean water distributin network in PDAM Tirta Khuripan, Bogor, West Java. By using the method of linear programing the result of optimization in PDAM Tirta Khuripan, Bogor, West Java diameter Optimal with Existing diameter ᶲ0.4 m range to ᶲ (0.15-0.35) (m) for pipes with Existing diameter ᶲ 0.25 m range to ᶲ (0.2-0.23) (m) and headloss loss analysis results in numbers / values of headloss that meet the standard which ranges from (0. - 4.0) (m). The draft total cost budget for distribution network optimization using LINGO software is IDR 4.291.967.000,00.

This paper utilizes a stochastic optimization approach using genetic algorithms, for conducting rigorous pipe size sensitivity assessments onto the design of pressure relief networks. By sampling high performance candidates, only the finest options can survive. The pressure relief network system that was investigated in this work was previously reported in literature. The problem is constrained and involves minimizing a cost objective function that evaluates the overall network performance, in which the best pipe size combination should be selected for each segment within the network. The overall goal of this paper was to seek cost-effective designs for the pressure relief piping system by exploring different ranges of pipe diameters that are available for each segment in the network and comparing how the overall design of the system is affected, when the number of pipe size options to select from is varied.

Gas flaring is concerned with the combustion of lighter ends of hydrocarbon mostly produced in association with crude oil. Flare networks are designed to handle the gas volume required to be flared. Most times, this flare networks are in close proximity but still have independent flare stacks, increasing risk to environment and cost on infrastructures. There is a need to integrate the flare networks in facilities within same area and through the application of Pinch Analysis concept, the resultant flare network can be optimized to give a system having optimal tail and header pipe sizes that will reduce cost and impact on environment. In the light of the foregoing, the concept of pinch analysis was used in debottlenecking integrated gas flare networks from a flow station and a refinery in close proximity. Both flare networks were integrated and the resultant gas flare network was optimized to obtain the optimum pipe header and tail pipe sizes with the capacity to withstand the inventory from both facilities and satisfy the set constraints such as Mach number, noise, RhoV2 and backpressure. Mach number was set at 0.7 for tail pipes and 0.5 for header pipes, noise limit was not to exceed 80 dB upstream and 115 dB downstream the sources, RhoV2 was limited to 6000 kg/m/s2 and the back pressure requirement was source dependent respectively. The fire case scenario was considered, as it is the worst-case scenario in the studies. When pinch analysis was applied in debottlenecking the combined gas flare network, it gave smaller tail and header pipe sizes which is more economical. A 20% decrease in pipe sizes was recorded at the end of the study.

Publisher Summary The standard piping detail is a drawing that depicts an item or items that are used with such frequency and having consistency in their installation procedure that a single drawing can be created and duplicated for use to represent their installation in almost every situation. This chapter discusses the methods and devices used for the support, anchoring, guiding, and spacing of pipes. Arrangement and positioning are important factors in the layout of a piping facility. Therefore, proper spacing and arrangement of pipes in a pipe rack require special attention. A pipe rack has a defined width; therefore, working within the allotted space makes spacing crucial. Pipes should be arranged to take up a minimum amount of space, and allowances should be made for any pipes that might be added in the future. A major concern when arranging pipes in a rack is the amount of expansion and, to an extent, contraction that occurs when a cold pipe is heated to its normal operating temperature. Expansion is not the only force that can alter the alignment of a pipe. Vibration, commodity turbulence, and other external forces—such as wind—cause a pipe to move.

Publisher Summary This chapter discusses manufacturing, wall thickness, and methods of joining of carbon steel pipe. Carbon steel pipe can be manufactured using several different techniques, each of which produces a pipe with certain characteristics. The chapter discusses methods to manufacture seamless, butt-welded, and spiral-welded pipes. Just as manufacturing methods differ, there are also different ways to categorize the size of a pipe. A pipe is identified by three different size categories: nominal pipe size, outside diameter, and inside diameter. “Wall thickness” is a term used to describe the thickness of the metal used to make a pipe. Wall thickness is also commonly referred to as a pipe's “weight.” Originally manufactured in weights known as standard, extra strong, and double extra strong, pipes have increased in complexity with the development of new chemical processes. There are several methods for joining pipes together. The three methods discussed in the chapter are those that are most widely used in piping systems made of carbon steel: butt-weld, screwed, and socket-weld. Not all piping systems require pipes designed to withstand the extreme conditions found in process-piping facilities. Cast-iron pipes, which have been in use for centuries, are used primarily in gravity flow applications—such as storm and sanitary sewers—and waste- and vent-piping installations.

Deadlegs are defined as pipe sections in intermittent use for production or special services in oil/gas production systems. Due to the absence of flow, deadlegs are commonly much colder than the ma...

Polyvinyl chloride (PVC) pipes have been extensively applied in water supply network fields. Understanding the mechanical properties and burst pressure of PVC pipes is necessary because a large number of pipes rupture due to excessive internal water pressure. In this paper, a practical approach based on the average shear stress yield (ASSY) criterion was proposed to assess the PVC pipe burst pressure. In addition, the PVC uniaxial tensile tests and the pipe burst tests were carried out to determine the material characteristic parameters and burst pressure of the PVC pipe. Furthermore, a finite element analysis (FEA) of PVC burst pressure was also performed based on the tangent intersection (TI) method to validate the proposed method and experimental results. Moreover, the impact of material parameters and pipe size, such as the strain hardening exponent and standard dimension ratio (SDR) on bursting pressure, were investigated. The comparison with the proposed theoretical model and the experimental and FEA results shows that the burst pressure derived from ASSY was consistent with the experimental data, with a relative error ranging from −2.76% to 2.65%, which is more accurate compared to other yield criteria. The burst pressure obtained by the ASSY approach declined with the increase of the hardening exponent n and increased with the increase of SDR. Therefore, the burst pressure solution-based ASSY proposed in this paper is an adequately suitable and precise predictive tool for assessing the failure pressure of PVC pipes.

The flattening and asymmetry of a pipe end section seriously affects the welding quality between pipes, therefore the calibration process for pipe end to improve roundness is essential. Because the calibration for a pipe end involves local elastic-plastic deformation for the end effect, it is still difficult to establish an accurate theoretical model. The reasonable and intelligent control method is nevertheless an effective means to improve the production efficiency. In this paper, an internal expansion over bending and calibration (IEOBC) process is introduced. According to the characteristics of the process, the structure of the mobile intelligent calibration machine for large pipe ends is designed, and the intelligent control hardware system of the machine is built. Based on the LabVIEW software platform, an intelligent control software system for the IEOBC process is developed. A three-step control strategy is combined with pipe size detection and ovality recognition. The intelligent prediction and execution of the calibration process parameters are realized. The experimental results show that the intelligent control system has good stability and accuracy, and the ovality can be controlled within 0.5%.

Computational Fluid Dynamics (CFD) is used extensively in the industry and academia for analyzing the motion of solid particles and the associated solid particle erosion that may occur in various pipe components. However, CFD simulations always carry levels of inherent uncertainties due to the numerical approximations of governing equations, generated grid, and turbulence models. Also, because of the complex nature of solid particle erosion, additional uncertainties are added to erosion prediction simulations. Aspects such as particle size, number of impacts, particles’ initial condition, near-wall mesh effects, forces considered in particle tracking procedures, particle-particle interaction, and near-wall particle-fluid interactions are all possible sources of uncertainties associated with erosion prediction in CFD. Furthermore, unique problems that accompany discrete phase handling and erosion calculation needed for the industrial applications magnify the importance of uncertainty estimation in erosion calculations. Commercially available CFD codes are used with user-developed subroutines to investigate particle erosion prediction uncertainties, numerically in elbows, by considering gas and liquid flow for several pipe sizes. Moreover, different particle sizes, inlet flow velocities, turbulence models, wall functions, and erosion models are examined. According to the ASME’s Verification and Validation (V&V) standard, uncertainties are divided into 3 categories; input, numeric, and modeling. Thus, it is possible to utilize the ASME’s standard as guidance to predict uncertainty for erosion simulations. Furthermore, an extra parameter was considered for uncertainties to account for the uncertainties induced by different simulation procedures and erosion models. The current investigations resulted in developing a framework for estimating uncertainties of erosion simulation. For each simulation result, two bounds (upper and lower) were predicted for erosion. The results show that the Reynolds Stress turbulence model (RSM) and Arabnejad’s erosion model usually predict results corresponding to the lowest uncertainties.

Supercritical CO2 (sCO2) can be utilized as a working fluid in various systems including high scale power cycle, portable power production unit, centralized cooling system and standalone cooling device. Lack of accurate predication tools such as heat transfer coefficient correlations and insufficient knowledge behind fundamental heat transfer processes can hinder its practical realization in key energy and cooling systems. The overall objective of the proposed study is to extend fundamental knowledge about heat transfer and fluid flow processes in conduits pertinent to sCO2 power cycle with an emphasis on buoyancy effects. Operational requirement of high pressures and temperatures for intended applications put a significant amount of constraints on measurement strategy and instrumentation. For this paper, experiments were conducted with uniform volumetric heat generation within pipe wall, for a single Reynolds number of 16,600 at test section inlet. The designed test apparatus and data reduction process are validated with high pressure air experiments, complemented by companion computations. Nusselt number was found to be within 10% of conventional correlations. For the test parameters and pipe size selected, factors of 2 to 4 variations in circumferential Nusselt number distributions are observed in sCO2 flow. Richardson number and other similar parameters to indicate importance of buoyancy-driven flow phenomena suggest that buoyancy forces caused by large density variation of sCO2 in flow cross-sections may cause the observed circumferential variations in Nusselt number.

A riser is a fluid conduit connecting from a subsea well to a surface floating production vessel such as a spar, TLP, or a semi-submersible. It is a key component for transporting produced oil and gas from the subsea wells to the surface production vessel. Through nearly 30 years of design and implementation, Steel Catenary Risers (SCRs) have been found to have the advantages of relatively low manufacturing cost and good adaptability to floating platform’s motion. Thus, SCRs are widely used in GoM and Brazilian water. This paper investigates design challenges of SCRs used for a semi-submersible in deepwater and ultra deepwater. As the application moves to deepwater and ultra deepwater, challenges of a conventional SCRs increase significantly in terms of global performance, fabrication, and installation. This paper first introduces an SCR system used for a semi-submersible platform. One of the challenges is the harsh environmental condition such as hurricanes or tropical cyclones. Severe motions of a semi-submersible platform may cause significant compression loads on SCRs at the Touch Down Zone (TDZ). It is challenging to design the SCRs to meet API RP 2RD requirement for the riser dynamic strength. Multiple seeds of random motion simulations for irregular wave are necessary for the evaluation. The new riser design code of API STD 2RD can also be used to assess riser strength, especially under 1000-yr survival environmental conditions. It is challenging to design SCRs to meet a design life of 30 years and beyond. The fatigue assessment of the SCRs considers the damage contributions from the semi wave motions, riser Vortex-Induced Vibration (VIV) due to ambient current, and Vortex-Induced Motion (VIM) of a semi-submersible platform. Fatigue contribution from installation is also considered and included in the combined fatigue damage calculation. The long term combined factored fatigue life is computed to ensure that the SCRs meet the requirement of design life. This paper further investigates intermittent Vortex-Induced Vibration (VIV) caused by heave motions of a semi-submersible platform. This VIV phenomenon has an impact on SCR strength due to the drag amplification as well as fatigue damage. The installation concerns come from riser pipe size, installation method and capacity of an installation vessel. Examples are provided for illustrations of the design challenges. In addition, this paper explores likely solutions to meet SCR design challenges for the applications in deepwater and ultra deepwater.

Hydrogen Manufacturing Units which have a Pre-reformer often use large diameter, thick-wall austenitic stainless steel (SS) piping operating at 540–650°C (1000–1200°F). In numerous units, circumferential welds in this piping have experienced failures due to stress relaxation cracking (SRC). Similarly, SRC has been reported in SS piping operating in this temperature range in hydroprocessing, olefin and coking units and in steam superheater coils in various units. This paper describes the in-service SRC mechanism and reports on some cracking case histories. It will also define how the risk varies depending on the process conditions, pipe size and thickness, fabrication steps and more. Additionally, this paper briefly lists the pros and cons of different material choices for this piping based on operating conditions, and ranks the materials for SRC resistance. Various other damage mechanisms also need to be considered and affect the optimum materials choice. The paper recommends steps for minimizing the risk of SRC of SS piping when SS is determined to be the preferred material choice. One of the key steps for providing resistance to in-service SRC is postweld heat treatment of the welds, but this has led to cases of reheat cracking during the fabrication stage. Guidelines for predicting and minimizing this risk are also reported.

Current flaw evaluation procedures for piping systems use elastic design analysis for secondary stresses (load-controlled), but fracture analysis is used for elastic-plastic loading behavior. The actual rotations/displacements of the pipe system that occur due to non-linear fracture behavior are much higher than the elastically calculated rotations/displacements. These actual non-linear rotations provide margins on the elastically calculated rotation values that come from uncracked pipe-design analysis. To account for this inconsistency, a Secondary Stress Weighting Factor (SSWF) was established which is the ratio of elastic-plastic moment to the elastic moment calculated through an elastic stress analysis. As long as the remote uncracked pipe stresses are below yield, the SSWF is 1.0, and if the uncracked pipe plastic stresses are above the yield stress, the SSWF reaches a limit which is called the Plastic Reduction Factor (PRF). A PRF was developed in an earlier investigation for outer diameter (OD) surface-cracked pipe tests at room temperature (RT). In this study, a PRF factor was developed for internal diameter (ID) surface-cracked pipes and elbows at an elevated temperature from recently conducted experiments. This methodology can be used on any pipe size, material, and pipe system geometry. To validate this methodology further, SSWF and PRF values were determined for ID surface-cracked pipes and elbows of two different materials at elevated temperature of 550°F with internal pressure of 2,250 psi. The PRF values at RT (70°F) and 550°F were compared. The two materials used in this study were TP304 stainless steel and Alloy600. Four-point bend pipe tests and elbow tests were conducted on pipes and elbows with varying circumferential surface crack sizes. The actual PRF value for a cracked pipe/elbow has a lower bound, which occurs when the test section of interest is at uniform stress. The center region of pipe in a four-point bend test is at uniform stress. A lower-bound limiting PRF value can also be calculated from stress-strain curves of pipe/elbow materials. Unlike tensile specimens, actual pipe systems are not uniformly loaded. Hence the reduction in stresses from the plasticity developed in the pipe system can vary depending on 1) loading conditions which determine if the pipe system experiences more elastic stresses or plastic stresses, 2) location of crack; if the crack is in a high strength/low toughness pipe or weld, plastic reduction is less, and 3) pipe size; if the pipe is large enough elastic-plastic conditions occur even for high toughness materials. Prior to developing SSWF or equivalent PRF, it is important to recognize the relative nonlinear-rotation/displacement contributions from the crack and the uncracked pipe adjacent to the crack. This nonlinear rotation/displacement is key to translating fracture mechanics predictions (that include large plastic behavior) back to elastic pipe-system design stresses. Examination of the pipe test data for different materials and under different operating conditions showed that with smaller flaws, the nonlinear rotation of the uncracked pipe was much larger than the nonlinear rotation from the crack; however, for large deep flaws (with failure stresses closer to potential operating/transient stresses) the rotation/displacement due to the crack was larger than from the uncracked pipe. Hence, both nonlinear rotation/displacement contributions are needed in the SSWF development to avoid excessive conservatisms.

In-pipe inspection robots are used to inspect the physical pipe conditions to reduce the likelihood of pipe failure because it can fit or be smaller than the pipe’s size for it to inspect the pipe’s interior. In this study, an improved design of an in-pipe inspection robot that can climb vertical pipes will be evaluated to determine if the designed chassis is acceptable through stress simulation and to analyze if the design has stable motion when traversing horizontal and vertical pipes. Before simulating the improved robot design in Adams, a simulation model will be made based on a fabricated in-pipe inspection robot to validate if Adams is a valid method for creating virtual prototypes. In the stress simulation, the results show that the design is acceptable as it did not have any deformation from the forces imposed on it during compression. The results of the simulation model based on the past study are shown to be almost similar to the actual results with less than 1% error that proves using Adams is valid for creating a virtual prototype. After evaluating the improved design by analyzing the mechanical behavior simulation model inside horizontal and vertical pipes with 6-8 inches inside diameter as well as comparing the displacement, velocity, spring force, and torque based on changes in pipe size and orientation, the design has shown to have stable motion and can climb vertical pipes without much issue.

While performing fatigue reliability analysis of the butt-welded joints it is vital to estimate the Stress Concentration Factor (SCF) at these joints. A common approach adopted by industry to estimate the SCF at weld toes is to perform Finite Element Analysis (FEA) of the welded joints for different pipe sizes, flanges, valves etc. The SCF are calculated for each size by separately when required and are very time consuming. Although FEA is known for its accurate SCF calculation, but due to its high computational expense and time-consumption, SCF evaluation for different parameters makes the aforementioned method quite laborious. As an alternative response surface models (RSM) may be used for accurate estimation of SCF. The two basic steps in constructing a RSM are training and testing. The first corresponds to fitting a model to the intelligently chosen training points, while the second step involves comparing the predictions of the RSM to the actual response. This paper examines the applicability of 12 different RSMs for estimating SCF. The training and testing data is generated using FEA in ANSYS. In order to compare the accuracy of the RSMs, three metrics, namely, Root Mean Square Error (RMSE), Maximum Absolute Error (AAE), and Explained Variance Score (EVS) are used. A case study illustrating the applicability of the proposed approach is also presented.

Drilling practice has been evolving parallel to the developments in the oil and gas industry. Current supply and demand for oil and gas dictate search for hydrocarbons either at much deeper and hard-to-reach fields, or at unconventional fields, both requiring extended reach wells, long horizontal sections, and 3D complex trajectories. Cuttings transport is one of the most challenging problems while drilling such wells, especially at mid-range inclinations. For many years, numerous studies have been conducted to address modeling of cuttings transport, estimation of the concentration of cuttings as well as pressure losses inside the wellbores, considering various drilling variables having influence on the process. However, such attempts, either mechanistic or empirical, have many limitations due to various simplifications and assumptions made during the development stage. Fluid thixotropy, temperature variations in the wellbore, uncertainty in pipe eccentricity as well as chaotic motion of cuttings due to pipe rotation, imperfections in the wellbore walls, variations in the size and shape of the cuttings, presence of tool joints on the drillstring, etc. causes the modeling of the problem extremely difficult. Due to the complexity of the process, the estimations are usually not very accurate, or not reliable. In this study, data-driven models are used to address the estimation of cuttings concentration and frictional loss estimation in a well during drilling operations, instead of using mechanistic or empirical methods. The selected models include Artificial Neural Networks, Random Forest, and AdaBoost. The training of the models is determined using the experimental data regarding cuttings transport tests collected in the last 40 years at The University of Tulsa – Drilling Research Projects, which includes a wide range of wellbore and pipe sizes, inclinations, ROPs, pipe rotation speeds, flow rates, fluid and cuttings properties. The evaluation of the models is conducted using Root Mean Square Error, R-Squared Values, and P-Value. As the inputs of the data-driven models, independent drilling variables are directly used. Also, as a second approach, dimensionless groups are developed based on these independent drilling variables, and these dimensionless groups are used as the inputs of the models. Moreover, performance of the data-driven model results are compared with the results of a conventional mechanistic model. It is observed that in many cases, data-driven models perform significantly better than the mechanistic model, which provides a very promising direction to consider for real time drilling optimization and automation. It is also concluded that using the independent drilling variables directly as the model inputs provided more accurate results when compared with dimensional groups are used as the model inputs.

This study addresses the optimization problem with the objective of designing a pipe network. An underground pipe network for geographically dispersed customers must be designed with consideration of the many candidate roads below which pipes are laid. The layout and pipe sizes must then be determined to minimize the pipe network construction cost. However, this problem has attracted little research attention to date. In this study, we first formulate mathematical optimization models under the assumption of a single source node in a planar graph. We then find that the cost-minimized pipe network has a tree structure if the diameter of each pipe is a continuous variable. Thereafter, we develop an exact algorithm based on dynamic programming. The time complexity of the algorithm is polynomial in the number of nodes, but exponential in the number of faces covering all demand nodes for a planar graph. In addition, we propose a method for assigning commercial pipe diameters to the tree using a commercial solver. The computational results for a real-world gas distribution network show that our method provides an efficient solution.

Water flow window has been demonstrated an energy-efficient product that benefits both air conditioning and hot water systems. Its thermal performance was found affected much by the design geometry and system configuration. For those based on buoyant-driven flow, liquid water is at very slow movement; the magnitude depends on the overall flow-path friction loss and hence the connecting-pipe arrangement. In this study, the impacts of such recirculating pipe-work have been examined extensively. Firstly, experiment tests were executed to evaluate the system performances with and without distribution headers. Then their thermal and flow characteristics were compared using CFD analysis. Further on, the impacts of connecting-pipe dimensions were examined through the use of a validated FORTRAN program. The optimal pipe size was determined accordingly. It was found that without headers, more uniform temperature distribution close to the glazing surfaces could be achieved. The system thermal efficiency could be improved by around 5%. On the other hand, the variation in room heat gain was found around 1%, as a result of the self-regulating nature of the buoyant-driven flow. For the given window system, an optimal pipe size of 20–25 mm is recommended.

In this study, a novel set of comprehensive arithmetic correlations has been proposed to design an industrial scale cylindrical reactor with embedded cooling tubes (ECT) for metal hydride (MH) based hydrogen storage and thermal management applications. Based on ASME standards, different nominal pipe sizes were imparted into a cylindrical reactor design with ECT to accommodate 50 kg of LaNi 4.7 Al 0.3 alloy. A three dimensional numerical model has been developed using COMSOL Multiphysics 4.3a to predict the hydriding performance of designed reactors, which was further experimentally validated as well. At an absorption condition of 30 bar supply pressure and 298 K absorption temperature with 60 lpm volumetric HTF flow rate, 6 inch reactor with 99 ECT portrayed better heat transfer characteristics. From the parametric investigation, it is observed that the variation of supply pressure has predominant effect followed by the variation of the HTF flow rate on hydriding (absorption) kinetics of the device. However, the variation of absorption temperature has minuscule influence on the hydriding performance. At a supply condition of 30 bar and 298 K with water flow rate of 30 lpm, a hydrogen storage capacity (HSC) of 1.29 wt% was achieved within 2060 s.

The most expensive portion of a large-scale district cooling system is the distribution network that conveys chilled-water to multiple buildings at controlled rates for use in comfort cooling. As the piping system needs large initial investment cost, a thorough investigation would be required to properly design the network. In order to come up with the solution a methodology for an optimal design of district cooling distribution network with loop-type system is needed. In this study, a district cooling distribution network model with loop-type system was investigated by calculating the system pressure drop, system volumetric flow rate and volumetric flow rate for each building. Friction factor identification, system simulation and optimization were performed based on the design temperature difference of 9°C with supply temperature of 4.5°C. The governing equations consisted of mass conservation, performance curve of variable primary flow pumping scheme, energy equations due to pipe friction and an equation that indicates the algebraic sum of head losses around any closed loop must be zero. Multivariable Newton-Raphson method was used to solve the system of nonlinear equations with the elements of solution vector determined using singular-value decomposition method. Exhaustive search method was used to solve the objective function and subsequently determine the piping network design criteria that yields minimum overall cost. Numerical results were also compared with traditional methods and have found some degree of similarities of pipe sizes except for pressure drop values exceeding 100 Pa/m.

In multiphase flow engineering operations, the pipelines that convey viscous fluids are subjected to interior friction where the pipe wall meets the fluid. The friction on the inner surface of the pipe causes energy losses. The losses are exhibited as a progressive pressure drop over the length of the pipe that varies with the fluid flow rate. This study develops a computational method to estimate the pressure change at any flow condition of multiphase flow (oil, gas, and water) inside a vertical pipe by developing fluid mechanics equations and using empirical correlations. Darcy and Colebrook friction factor correlations were used to ratify the predicted frictional pressure drop by computational method outcomes. OLGA dynamic simulation software was used to validate the accuracy of the computational method results. A sensitivity analysis was performed to evaluate the performance of the developed computational method, by using different well flow rate, pipe size diameter, and fluid properties. The frictional pressure drop estimation by computational method has acceptable accuracy and it is located within the accepted average relative error band (±20%). The overall performance of the method is satisfactory when compared with other observations.

A Mixed Integer Linear Programming method for the optimal valorisation of regional waste heat, formulated for energy service companies, is proposed in this work. The model provides a framework to simultaneously optimise the multi-period exchange of waste heat between regional thermal sources and sinks, as well as the selection of the backup heating technology. Given the pre-defined cost contributions of the involved sources, the sinks, the heat transport infrastructures and the heating technologies, the configuration is optimised by maximising the system profitability. The approach accounts for variations of temperature levels and heat loads across periods for the same sources and sinks, considers specific energy prices for multiple competing sinks and provides a predesign of the waste heat distribution network considering standard pipe sizes. The method is applied to the southern region of Luxembourg, composed of two steel production plants (heat sources), as well as three factories and nine towns (heat sinks). The impact of the waste heat buying price on the profits, revenues, valorised heat and electricity production quantities is assessed. For prices between 0 and 5 €/MWh, electricity production is a viable solution, while for prices between 0 and 25 €/MWh, the heat can be valorised in the urban systems.

Polyethylene (PE) pipes are widely used in gas transmission projects due to their excellent performances. Earthquake is destructive and difficult to predicted, which is one of the major disasters caused PE pipe failure. The study was conducted on the mechanical behaviors and failure mechanisms of buried PE pipes under fault movement, and the effects of gas pressure, fault dislocation, soil and pipe size on the mechanical behavior of PE pipes were discussed. The study indicates that gas pressure has a less effect on the mechanical behavior of PE pipe. Under faults, the flatness curve of PE pipe is distributed symmetrically with respect to the fault plane. Deformation rules of PE pipe in different stratums are similar, while the pipe deformation is the largest in clay and it is smallest in sand. The greater the standard pipe size, the greater the diameter flatness coefficient is. The larger the diameter, the smaller the pipe diameter flattening parameter is. PE pipes with a larger standard dimension ratio of a fitting (SDR) and a smaller diameter are prone to failure in fault zone. The results can provide a basis for gas pipe design, laying, testing, and evaluation.

Based on the Hill yield criterion, considering three directional stress (r, θ, z) of pressure pipe, the analytical solution for limit load of orthotropic pressure pipe with constant-depth internal circumferential crack under combined pressure, axial force and bending has been derived. The effect of crack size, anisotropy of pipe material, load (pressure, moment), and pipe size on the limit load of orthotropic pressure pipe is discussed. The results show that it is necessary to consider three directional stress for thick-walled pipe, and the influence of radial stress on the limit load cannot be ignored for thick-walled pipe. The limit load of pipe with constant-depth internal circumferential crack decreases with crack size. The limit load of pipe under pure bending is only related to axial yield strength. The limit load of pipe under pure internal pressure is mainly determined by circumferential yield strength.

The current work seeks to perform the one-dimensional drift-flux analysis for horizontal gas-dispersed flow, to provide closure models for void fraction and to investigate the relative motion between gas and liquid phases. A reliable experimental database for void fraction and bubble velocity is first established over a wide range of flow conditions for bubbly, plug and slug flows in different pipe sizes, due to the limitations of existing database. It is found that the effects of flow regime and pipe size on the drift-flux analysis are insignificant. The drift velocity is found to be negative in horizontal bubbly flow. This is consistent with the conclusion by the 〈α〉–〈β〉 analysis, where the slope is found to be greater than one. This indicates that the gas phase moves slower than the liquid phase in horizontal bubbly flow. The analysis also indicates that the horizontal plug and slug flows are relatively more homogeneous than horizontal bubbly flow. As such, the homogeneous flow model can predict the void fraction better for plug and slug flows. The current drift-flux analysis provides closure relations for C0 and 〈〈Vgj〉〉 that can be employed in TRACE, while existing closure relations are developed for vertical flow and cannot be used for horizontal flow prediction. In addition, various void fraction models in literature are evaluated. It is found that the correlations modified from vertical flow generally cannot predict the void fraction well for horizontal flow. The correlations for plug and slug flows by Franca and Lahey, and Lamari underestimate the void fraction, which may be because these correlations are developed for relatively low jf conditions, while the current work focuses on conditions at jf greater than 2.0 m/s.

To reduce the heat flow between building interior and exterior environments using thermal energy storage without causing problems related to moisture transfer, this paper presents residential building walls enhanced with pipe-encapsulated phase change materials (PCM). Experimental investigations are conducted to identify thermal performance of building walls with pipe-encapsulated PCM in typical summer conditions. A dynamic wall simulator was designed and built to reproduce residential building indoor and outdoor conditions in a laboratory setting. Two pipe sizes, based on diameter, installed in a horizontal arrangement and placed at various wall depths were investigated. The heat transfer through building walls with pipe-encapsulated PCM was evaluated based on peak heat flux reductions and peak heat flux time shift. The peak heat fluxes of the PCM-outfitted walls were reduced by a maximum of 22.5% for what was referred to as “next to wallboard” configuration and 36.5% for “middle depth” configuration, respectively, compared to standard walls. The corresponding daily energy savings were 27.4 W-hr/m2 and 51.2 W-hr/m2. PCM encapsulated in smaller pipes installed in the “middle depth” of the wall cavity is recommended to realize complete solidification and melting for larger peak flux reduction and energy savings.

In tropical countries like India, irrigation is necessary to grow crops in the nonmonsoon period. The conventional methodology for conveying irrigation water from the source to the field is through open canals. However, considering huge losses due to evaporation and percolation, a modern system of irrigation like pipe irrigation network (PIN) is desired. Advancement in technology has led to the progress in the PIN as they are compatible with modern irrigation facilities such as sprinkler and drip irrigation systems. In the present study, the layout of the PIN is designed and optimized in two phases. Initially, the looped network is traced out for the Bakhari distributary of the Kanhan Branch Canal, India. Minimum spanning tree (MST) network is obtained from the looped network using Prim's algorithm to calculate the nodal demands. The layout optimization of the MST is carried out using the Steiner concept to obtain the initial Steiner tree (IST). The steady-state hydraulic analysis and design are carried out for the looped and IST network. The results show that the percentage of length decreasing from the looped network to the MST network is 51.58%. The IST network is the optimized network having the minimum length showing a 12.21% length reduction compared to the MST network. The total reduction in the cost of the Steiner tree is found to be 4.25% compared to the looped network. Steiner concept application to large irrigation networks can reduce the length of the network thereby minimizing the total project cost.

An innovative tube bending process supported by hydraulic pressure was patented in 1995. This process was designed for producing butt-welding fittings which particularly fulfil the dimensional specifications of the ASME B16.9, MSS SP-75, and MSS SP-43 standards. Since the patent has meanwhile expired, the bending process is now available for common use. This work presents a novel finite element (FE) model build using the software package LS-DYNA, which enables determining the process window for bending defect-free butt-welding fittings. This model was exemplarily applied for investigating the bending process of a 90° stainless steel elbow based on a straight tube of nominal pipe size (NPS) 6. Comparing the calculated geometry of the elbow with the actual geometry of an industrially produced elbow revealed very good dimensional agreement. This confirms that the presented model can be utilized for determining suitable process conditions, which allow for producing defect-free components.

This article deals with the problem of finding the best topology, pipe diameter choices, and operation parameters for realistic district heating networks. Present design tools that employ non-linear flow and heat transport models for topological design are limited to small heating networks with up to 20 potential consumers. We introduce an alternative adjoint-based numerical optimization strategy to enable large-scale nonlinear thermal network optimization. In order to avoid a strong computational cost scaling with the network size, we aggregate consumer constraints with a constraint aggregation strategy. Moreover, to align this continuous optimization strategy with the discrete nature of topology optimization and pipe size choices, we present a numerical continuation strategy that gradually forces the design variables towards discrete design choices. As such, optimal network topology and pipe sizes are determined simultaneously. Finally, we demonstrate the scalability of the algorithm by designing a fictitious district heating network with 160 consumers. As a proof-of-concept, the network is optimized for minimal investment cost and pumping power, while keeping the heat supplied to the consumers within a thermal comfort range of 5 %. Starting from a uniform distribution of 15 cm wide piping throughout the network, the novel algorithm finds a network lay-out that reduces piping investment by 23 % and pump-related costs by a factor of 14 in less than an hour on a standard laptop. Moreover, the importance of embedding the non-linear transport model is clear from a temperature-induced variation in the consumer flow rates of 72 %. ispartof: Applied Energy vol:280 status: published

Chemical cleaning is used in gas pipelines to remove debris that was resistant to mechanical cleaning. The cleaner is a liquid mixture of a hydrocarbon-based solvent and a surfactant. It is transported down the pipeline either batched between two cleaning tools or pushed by a single tool. During a chemical cleaning run, liquid will leak into any side branch it passes. Consequently, gas quality problems may arise when the pipeline returns to regular operations as the leaked liquid hydrocarbons evaporate into the gas stream. Furthermore, operational problems such as flooded separators can occur if a large volume of liquid is lost. Currently, there is no understanding of what factors influence the liquid’s leak rate into side branches. This paper aspires to address this knowledge gap. A water flow loop was set up to investigate the effect on leak rate of mainline pipe size, side branch pipe size, side branch length, and mainline liquid velocity. The leak rate is found to increase with the side branch pipe size, while remaining unaffected by the mainline pipe size and side branch length. At mainline velocities below the critical velocity, gravitational effects such as the downstream back pressure significantly affect the leak rate. At mainline velocities above the critical velocity these effects disappear, and the leak rate decreases as the mainline liquid velocity increases.

Robots for pipe inspection have become more prevalent in recent years, and expanding the capabilities of these robots is of interest. Specific needs include accommodating a larger range of pipe sizes without needing customized robots, and navigating sharp bends in pipe networks. This paper presents a new pipe robot architecture with emphasis on a novel multi-link wheel-leg design. Favorable properties of the kinematics and kinetostatics of the robot are illustrated through analysis and simulation, and bounds for feasible component dimensions based on task descriptions are presented.

Transported Newtonian settling slurries (mixtures of solid particles and carrying liquid) tend to stratify in a slurry pipeline and the degree of their stratification significantly affects the frictional head loss in a pipeline system. Solid particles can span a broad range of sizes from those typical for fine sand to those typical for coarse gravel. Different fractions of solids have different properties and form different flow patterns. The different patterns are associated with different dominating particle support mechanisms and friction mechanisms in slurry flow. Hence, there are different models describing and predicting the frictional head loss in pipe flows of different settling slurries. In the presented work, we focus on friction-loss models for heterogeneous (partially-stratified) flow (V50-model), and for fully-stratified flow (Vsm-model). The models can serve as tools to scale up information on frictional head loss in flow of specific slurry obtained experimentally in a small laboratory pipe to larger pipes of industrial sizes. So far, the reliability of the scale up has been difficult to verify as an availability of coarse particle experimental data was restricted to small laboratory pipes (an internal diameter of a pipe typically not larger than 100 mm) and data from larger pipes were extremely scarce. In 2016 and 2019, extensive experimental campaigns were conducted in the GIW Hydraulic Laboratory (Grovetown, GA, U.S.A.) testing flows of Newtonian settling slurries in pipes of 3 very different sizes (103 mm, 203 mm, and 489 mm). We exploit the experimental data to evaluate the pipe-size scale-up ability of the heterogeneous V50-model and the stratified Vsm-model. The evaluation includes an analysis of the pipe-size effect on the characteristic velocities of the models: the suspension velocity V50 and the deposition-limit velocity Vsm.

This study discusses practical implications of considering unit head loss in different pipe sizes and in different locations of water distribution systems (WDSs) with regard to operation and maintenance. By visualizing unit head loss (using the Hazen-Williams relationship) in pipes obtained from 18 WDSs in North America, changes in unit head loss are put into perspective in different pipe sizes and different WDS locations. The results suggest that the importance of diameter is greater than that of the Hazen-Williams roughness factor, that flow rate plays a more important role than diameter in determination of head loss in pipes closer to water sources, and that diameter seems to be more important than flow rate in pipes at the periphery. Moreover, aging, tuberculation, and subsequently reduction in effective diameter can have a more critical effect on head loss in smaller pipes at the periphery of a system. Finally, effects of water conservation and pump scheduling in different locations of the network, as far as head loss is concerned, can potentially be more evident on larger pipes closer to the water source and in some cases on smaller pipes at the periphery. Therefore, it is suggested that network-level energy management decisions can have different effects on different pipe sizes in different locations.

The T-junction has been extensively employed in nuclear power plant systems. To ensure the normal operation of nuclear power plant, the onset point of T-junction liquid entrainment requires in-depth studies. Existing studies have been conducted on the onset point of liquid entrainment, whereas most of them are for small branch pipes. This study primarily discussed the onset law of large branch pipe. Moreover, the effects of branch angle and size on the onset point of liquid entrainment were analyzed by comparing it with other branch pipe sizes in this study. This study demonstrated that the effect of branch angle on the onset point of entrainment complies with that of other sizes, i.e., because that the decrease in the inertial force in the vertical direction acting on the liquid phase by the gas phase with the decrease in the angle, hence, the onset requires larger Frg under the identical hbwith the decrease in the angle between the branch pipe and the horizontal direction. Moreover, by comparing the onset point law of liquid entrainment exhibiting different branch pipe sizes, the effect of branch pipe size on the onset was reported in this study that the smaller branch pipe requires the greater gas velocity in the presence of onset. We found that there is different flow resistance of different sizes of branch pipe, small branch has larger flow resistance, in order to remedy the flow resistance, the gas dynamic head decreases, thereby causing the Bernoulli effect weaker; the onset of liquid entrainment requires larger V3g.

PT. Pertamina Hulu Energi Ogan Komering (PHE OK) Water injection began in 1998, by injecting excess water in abandoned wells in Central ASD and continued in October 2000 and January 2002, and since May 2006 the injection rate was increased above 30,000 BWPD. From the analysis carried out, one of the obstacles in the injection water process at PHE OK is the main pipe capacity of the injection water which is getting smaller and the pressure drop along the pipe is very big. The pressure drop occurs due to the solid / deposition pile on the inside of the pipe, causing obstacles in the process of transferring injection water from the Block Station to the injection wells. From the laboratory analysis, the solid deposits inside the pipe wall is consist of more than 50% organic and hydrocarbon matters (paraffin, oils, and light asphaltene) often called as “Schmoo” deposit. Some pigging activities can not be done due to pipe size, pipe geometry that does not support, pipe construction that is not designed for pigging activities. To overcome the solid deposit problem, PHE OK carried out a field trial of Schmoo Remover Chemical to clean the pipe without using pipe pig. From the field trial result, the removal of the schmoo solid deposit resulted in a significant increase in water injection rates and decrease pipe pressure drop.

This study aims to experimentally investigate the two-group interfacial area transport in small diameter pipes. Experimental data focusing on the bubbly to slug transition regime, namely one-group to two-group transport region, are collected in a 12.7 mm vertical pipe under adiabatic, air-water conditions. The result shows the intergroup transfer in the small diameter pipe can be drastic, especially under low superficial liquid velocities. The cause of this phenomenon is mainly due to the large relative bubble size comparing to the pipe cross-sectional area. The wake entrainment effect could be enhanced by the small spherical bubbles that are acting like cap or slug bubbles in a medium-size pipe. Based on the experimental observation, a throughout analysis of the dependence of the drastic intergroup transfer is provided in this study. The models predicting the initiation of drastic intergroup transfer in small diameter pipes in terms of the bubble diameter and the void fraction are developed. These models are compared with the two-phase data among the different pipe sizes and the results show a good agreement. These newly developed models are applied to the IATE wake entrainment model by developing a transition function analogous to the sigmoid function. With the transition function, the revised IATE model is given the new ability on predicting the drastic intergroup transfer phenomenon.

We are ready to consider the grid. The favorable hydraulic characteristics of a gridded sprinkler system permit relatively small pipe sizes and uniform pipe sizing, which translate into lower costs.

Urban Drainage System (UDS) design has been performed to determine the pipe layout and sizes mostly by optimization-based models. However, function evaluations of the UDS design problem are often very time-consuming because of the computation time for rainfall-runoff and network hydraulics of Strom Water Management Model (SWMM). Therefore, various surrogate models have been proposed during the last decade to overcome the limitation. This study first proposes a hybrid models that combine an optimization method and a surrogate model based on Artificial Neural Network (ANN) for UDS pipe layout and size optimization. Then, various versions of the proposed model are applied to the design problem of a real large urban drainage network: (1) Version 1 determines the optimal pipe sizes by the optimization module whereas the pipe layout is derived from the ANN module; (2) Version 2 determines the former by the ANN module, and the latter by the optimization module; and (3) Version 3 produces the optimal pipe sizes and layout solely by the ANN module. We compared the three different versions with respect to their computational efforts and times and estimation accuracy (e.g., Mean Square Error and R2). Finally, this study will provide guidelines for using the hybrid models in the UDS design.

The contribution of this paper is a comparison of the installation cost of a conventional drainage system consisting of a network of pits and pipes, with that of a hybrid drainage system comprising a network of pits and pipes, supported by allotment scale infiltration measures in a modern greenfield residential development. The case study site is located in Pipers Crest, near Strathalbyn, South Australia. This as‐built site consists of 56 allotments, 42 pits (hence 42sub‐catchments), one detention basin and over 1000 m of drainage pipes. In this study,conventional and hybrid (combination of conventional and Water Sensitive Urban Design, WSUD systems) drainage systems were designed to convey minor storm events of 10% annual exceedance probability (AEP), and checked for major storm events of 5% AEP, using the DRAINS model and/or source control principles. The installation costs of the conventional and hybrid drainage systems were estimated and compared based upon cost estimates derived from Australian literature. The results of the study indicate that satisfactory drainage was possible using the conventional or hybrid system when the two systems were designed to have outflow not exceeding the pre‐developed flow. The hybrid drainage system requires smaller pipe sizes compared to the conventional system. Also, the size of the detention basin and maximum outflow rate of the hybrid system were smaller than those for the conventionally drained site. The installation cost of the hybrid drainage system was 18% less than that of the conventional drainage system when the objective was to accommodate 10% and 5% AEP storms. Refereed/Peer-reviewed

DIMSUB is a computer program to complement a decision support tool (DST) to effectively study different hydraulic design alternatives in microirrigation systems. We developed environments in Visual Basic for applications for Microsoft Excel® that allow specific step-by-step functions to be created for the design of irrigation subunits. Different alternatives can be considered, such as types of emitter, lateral and submain pipe sizes, different feeding points, irregular subunit shapes and topography slopes. Furthermore, specific uniformity criteria need to be considered to achieve efficient water applications and proper design systems. Lengths of run lateral and submain pipes, position of the hydrant connection, pressure head and head loss in pipes or pressure-compensating emitters can be assigned to evaluate the results and choose the best design alternative. This user-friendly tool to study hydraulic variables is expected to be a valuable aid for the decision-making process in designing irrigation systems. Some examples of practical cases under specific crop conditions to design drip irrigation subunits are given using DIMSUB.