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Industrial steam heating is a significant aspect of energy consumption in China, playing a crucial role in industrial energy efficiency. Historically, demand response research has predominantly focused on the electricity sector, with limited emphasis on steam supply. This study explores a novel Time-of-Use pricing approach for steam heating systems, anchored in the demand response theory of price incentives. It develops a peak-valley segmentation method by considering both the load differences between supply and demand and the thermal storage capacity of the pipeline system. Additionally, the paper delves into user response characteristics to formulate an optimized Time-of-Use pricing model for steam heating systems. Implemented in a Jiangsu-based case study, the model demonstrates significant efficiency improvements: it reduces the peak-valley load difference by up to 68.3% and cuts steam purchasing costs by ¥135,000. Furthermore, the alignment between the users' total steam load curve and the heat source's steam supply is enhanced by 18.8%, illustrating the model's effectiveness in balancing demand and supply. • Cluster analysis to extract steam user load characteristics. • Divide peak/valley times based on network storage and user traits. • Create a multi-objective Time-of-Use model for steam pricing optimization. • Carry out a case validation in an actual industrial park in Jiangsu. [ABSTRACT FROM AUTHOR]

Support insert run-flat tire is a kind of safety tire based on common tire structure. It has the advantages of simple structure, easy disassembly and strong bearing capacity. However, when driving under zero-pressure condition, it can not meet the requirements of heavy load, high mobility and long-distance. Aiming at this problem, the finite element model is established. The load and contact patch characteristics of the model are simulated by ABAQUS. The radial stiffness curve and the contact pressure distribution under zero-pressure are obtained. The results show that the radial stiffness curve presents a certain nonlinearity in the sidewall loading stage. When the insert contacts the tire, it is approximately linear. The contact pressure distribution cloud diagram under zero-pressure condition shows that there is warpage. The tire test bench was set up and the relevant test scheme was formulated. The radial stiffness curve and the footprint of the support insert run-flat tire under zero-pressure condition were obtained. The research results show that the simulation and test results are in good agreement. This research is of great significance to the performance analysis of whole support insert run-flat tire under zero- pressure condition. [ABSTRACT FROM AUTHOR]

P‐I diagrams are widely used for structures subjected to blast loads. In the same manner, structures subjected to vehicle impact load, such as bridge columns, could potentially take advantages of the P‐I diagram if the dynamic characteristics of vehicle impact load and bridge columns are well considered. In the paper, the performance of bridge columns and hence the use of P‐I diagram is evaluated under vehicle impact load. The main tasks of the paper are (1) to determine the dynamic characteristics of vehicle impact load through finite element method, and three simplified load shapes are obtained including isosceles triangle, right triangle, and rectangular shapes; (2) to investigate structural failure modes under various shear‐bending ratios and impact loads; (3) to establish the damage index based on the residual axial capacity of bridge columns and to obtain P‐I diagrams at different damage levels of bridge columns under vehicle impact load; (4) to parametrically analyze the effects on the impulse asymptotic and the peak load asymptotic of P‐I diagrams, including column diameter, stirrup reinforcement ratio, longitudinal reinforcement ratio, and strength of the concrete. Finally, a simplified calculation method of P‐I diagrams is proposed to evaluate the performance of bridge columns under vehicle impact load. [ABSTRACT FROM AUTHOR]

In order to research the new integrity evaluation technology of gas pipeline and promote the mature development of gas pipeline integrity management, this paper deeply analyzes the characteristics of Beijing gas pipeline and combines with the methods of finite element modeling, statistical analysis, mathematical fitting and experimental verification. Based on the Spangler-lowa method, the load effects of gas pipelines with different pressure grades are analyzed, a new method for evaluating the external load carrying capacity of gas pipeline with local corrosion defects was developed, and a method for evaluating the internal pressure carrying capacity of gas pipeline was determined. The research shows that the integrity structure evaluation of gas pipeline should be evaluated according to the pressure level. Medium- and low-pressure gas pipeline is mainly affected by external load, and deformation is the evaluation basis. The sub-high-pressure gas pipeline is affected by both external load and internal pressure, and its deformation and stress are taken as the evaluation basis respectively. High-pressure gas pipeline is mainly affected by internal pressure, and stress is the evaluation basis. [ABSTRACT FROM AUTHOR]

Helical magnetic flux compression generators (HFCGs) are widely used to generate extremely highpower pulses. Two most important output characteristics of HFCGs in their use as pulsed power generators are maximum value of load current and the rise time of that current. In this paper, an approach is proposed to improve the output characteristic of a Cascaded-HFCG. The approach is based on time-varying primary winding of dynamic transformer and addition of a gradually incremental resistance in series with the first stage winding. It is demonstrated analytically using simulation results that the output current and its rise-time improve by minimizing energy returned from secondary winding to primary winding of dynamic transformer. The results are compared to conventional Cascaded-HFCG that has a non-destructive winding in its structure. A finite element model is considered to calculate the selfinductances, mutual inductance and resistances of the generator. A new approach is proposed to gradually increase in the resistance of primary winding of dynamic transformer. [ABSTRACT FROM AUTHOR]

The object of research in the work is hydrodynamic processes in the high pressure fuel system of the ship’s medium-speed engine on variable modes. Variable regimes constitute a significant part of the operational time of a number of types of ships (tugs, fishing vessels, etc.), and for transport fleets they are characteristic for maneuvering. In the latter case, reliability and environmental safety for sanitary control zones are of particular importance. Studies of fuel supply processes in variable modes are important, since they largely determine all the operating characteristics of a diesel engine and are not well studied The article presents an experiment in which the task is obtaining the load characteristics and the study of transients in the fuel equipment of the ship’s medium-speed diesel engine under dynamic testing conditions. In the course of the research, a developed hardware and software complex is used to ensure the implementation of the experiment plan, fixation, processing and oscillography of the obtained data. An electromechanical system is developed by rack displacement of a high-pressure fuel pump with programmed computer control. The experiment program provides for changing the rack position in the whole range covering the operational load characteristic. The discrete displacement includes five fixed rack positions with a step transition between them. During testing, the high-pressure fuel pump completes 80 injection cycles over 44 s. The transition time between the individual fixed positions of the racks is 0.44 s. The stabilization period of hydrodynamic processes in the fuel supply system is close to 0.22 s. In the investigated range of rack positions mr = 25–5 mm the main parameters of the fuel injection are as follows: рn.с = 474–232 bar; рn.i = 457–222 bar; рp = 445–162 bar. The possibility of obtaining load characteristics by dynamic tests is shown, which significantly reduces the test time and increases the reliability of the data, eliminating the influence of the time trend parameters. [ABSTRACT FROM AUTHOR]

The conventional pneumatic tires have disadvantages in terms of puncture, blowout at high speed, pressure maintenance, and so on. Due to these structural inevitable weaknesses, non-pneumatic tires have been developed and are being investigated. A new non-pneumatic elastic wheel was proposed and studied to solve these problems. As an important bearing member of the non-pneumatic elastic wheel, the force of hinge group is very complex and it has a significant effect on the performance of the wheel. However, in the complex off-road driving, the hinge group has to withstand complex random load and impact load, and inevitably there will be damage failure. In order to explore the performance change of the wheel after the failure of the important bearing parts, it is necessary to study the influence of the hinge group with local damage on the performance of the non-inflated elastic wheel. In this paper, an experimental study on basic characteristics of non-pneumatic elastic wheel with local hinge group fracture damage was conducted in order to enhance the reliability. Based on tire characteristic test-bed, the tests on basic characteristics of static radical stiffness and contact behavior as well as the modal test were conducted. The wheel with local damage, one hinge group of which was disassembled, was used to simulate hinge group fracture condition in this paper. The results show that the effect of the hinge group fracture damage on the wheel load characteristics is the decrease of the radial stiffness, and it is also related to the damage position on the non-pneumatic elastic wheel. The radial stiffness of non-damaged non-pneumatic elastic wheel is 593.06 N/mm, and the corresponding values of the non-pneumatic elastic wheel with fractured hinge group on horizontal position and vertical position are 443.2 and 385.4 N/mm, respectively. Compared with non-damaged non-pneumatic elastic wheel, the numerical value of radial stiffness is reduced by 25% and 35% respectively on horizontal position and vertical position when the fractured hinge group is installed. That is to say the consistency of radial stiffness and deformation uniformity get worse for the wheel with local damage, so the poor performance of riding comfort of non-pneumatic elastic wheel appears. The influence of the hinge group fracture damage on the grounding pressure distribution is the change of grounded imprinting length and grounded area. Under the same vertical load, these 2 indicators of the non-pneumatic elastic wheel with fractured hinge group increase compared with non-damaged non-pneumatic elastic wheel. When the vertical load is 7 262 N, the imprinting length of the non-pneumatic elastic wheel with fractured hinge group on horizontal position is 138 mm, and the numerical value of non-damaged non-pneumatic elastic wheel is 120 mm. The ground imprinting length of the damaged wheel is increased by 15% compared with that of the non-damaged non-pneumatic elastic wheel. The grounded imprinting width does not change, and the value remains at 285 mm. As a result, the total grounded area of the damaged wheel also increases. The area of the non-damaged non-pneumatic elastic wheel is 34 200 mm2, and the area of damaged wheel increases to 39 330 mm2. The contact length and area of the wheel with local damage are greater than corresponding values of the non-damaged non-pneumatic elastic wheel under the same load. The influence of the hinge group fracture damage on the wheel modal test is the change of the natural frequency, the damping coefficient and the modal shape. In addition to a few orders, the natural frequency of non-damaged non-pneumatic elastic wheel is greater than that of non-pneumatic elastic wheel with local damage hinge group, and the damping coefficient of the most of non-damaged non-pneumatic elastic wheel is less than that of non-pneumatic elastic wheel with local damage hinge group. The value of the amplitude of modes gets smaller for the non-pneumatic elastic wheel with local damage hinge group. [ABSTRACT FROM AUTHOR]

Zhang, Z.; Wang, L.; Yao, X., and Lang, J., 2017. Dynamics of an underwater explosion bubble near a rigid wall: Effect of slenderness ratio, installation, and distance parameter. Structural damage of maritime construction ( e.g., dams, warships, etc.) has received considerable international attention in recent years because of underwater explosions from accidental events and terrorist bombing attacks. Therefore, research studies on underwater explosion load characteristics will have a great influence on the future of coastal and maritime engineering. Here, level set-direct ghost fluid-Runge Kutta discontinuous Galerkin method and boundary element method are combined to establish a model of underwater explosion near a rigid wall. First, the hybrid algorithm is used to simulate the process of underwater explosion in free field; the results agree well with experimental data, proving the effectiveness of the algorithm. Second, the process of underwater explosion near a rigid wall is simulated by the presented method. Finally, effects of parameters - slenderness ratio, installation (horizontal and vertical), and distance from the center of the explosive to the rigid wall - are investigated on shock waves and bubble dynamics. It is found that during the detonation process, the ellipsoidal bubble gradually turns into a spherical one. The radial pressure peak value is higher than the axial one. During the collapse phase, the slenderness ratio and the installation have little effect on bubble shape, maximum radius, and pulsation cycle. During the bubble-jet process, a high-speed jet penetrates the bubble toward the rigid wall and generates a high-pressure region on the bubble wall. For the charge placed vertically, the jet velocity rises while the jet width decreases as the slenderness ratio increases; results for horizontal cases are opposite. The jet velocity in the vertical case is lower than that in the horizontal case; on the contrary, the jet width is larger. With the increase of the distance parameter, the pressure on the upper surface of the bubble and the jet velocity are higher, whereas the jet width is smaller. [ABSTRACT FROM AUTHOR]

This work uses the mathematical model of an intermediate-temperature solid oxide fuel cell and gas turbine (IT-SOFC/GT) hybrid system to study the effects of gasified biomass fuels on system load characteristics. The system performance is investigated by using four types of fuels in each adjusting mode. The relation between the fuel type and load adjusting mode is obtained for users and designers to select the appropriate fuel for reasonable operation modes. Results show that the hybrid system of 182.4 kW has a high electric efficiency of 60.78% by using wood chip gas (WCG). If cotton wood gas (CWG) and corn stalk gas (CSG) are used, both boundary values of steam to carbon ratio (S/C bv ) and system power are higher, but system efficiencies decrease to 57.36% and 57.87% respectively. In the designed three load adjusting modes, the system can reach maximum efficiency over 59% with four types of biomass gases. If high efficiency and a wide range of load adjustment are required, users can select Case B to use fuels like WCG and GSG. When higher efficiency and low load is expected, Case A is more desirable. With fuels like CWG and CSG, the system has good safety performance in Case C. [ABSTRACT FROM AUTHOR]

In the high speed rotational gearbox, the tooth surfaces of gears are usually crowned with twist-free tooth flanks to reduce the vibration and noise of the gear systems due to the transmission error and load variation. In this paper, a method for longitudinal crowning tooth flank of work gear surfaces is proposed by setting a crossed angle between the honing cutter and work gear axes as a linear function of work gear's traverse feed and a variable pressure angle (VPA) honing cutter is also used for free twist of the crowned tooth flank in the external honing process. Besides, the transmission and load characteristics of the gear pairs using a crowned pinion with twist-free tooth flanks are need to understand. Therefore, 3-D models of the meshing gear pairs with twisted and twist-free tooth flanks are constructed and analyzed by using KISSsoft software. Three numerical examples are presented to illustrate and verify the merits of the proposed gear honing methodology as well as shed light on the transmission and load characteristics of the gear pairs with twist-free tooth flanks. [ABSTRACT FROM AUTHOR]

This paper introduced the modeling method of exciter's excitation system，taking exciter's excitation system of 200 MW unit of a certain power plant in Heilongjiang as a research object，verified the feasibility of model establishment method through comparative analysis of the small disturbance test results and the simulation results，which provided the accurate calculation data for the stable operation and analysis of the power grid. [ABSTRACT FROM AUTHOR]

Methanol is a promising alternative fuel for the spark-ignition engines. This paper experimentally investigated the performance of a hydrogen-blended methanol engine at lean and various load conditions. The test was conducted on a four-cylinder commercial spark-ignition engine equipped with an electronically controlled hydrogen port injection system. The test was conducted under a typical city driving speed of 1400 rpm and a constant excess air ratio of 1.20. Two hydrogen volume fractions in the intake of 0 and 3% were adopted to investigate the effect of hydrogen addition on combustion and emissions performance of the methanol engine. The test results showed that brake thermal efficiency was improved after the hydrogen addition. When manifolds absolute pressure increased from about 38 to 83 kPa, brake thermal efficiencies after the hydrogen addition were increased by 6.5% and 4.2%. The addition of hydrogen availed shortening flame development and propagation periods. The peak cylinder temperature was raised whereas cylinder temperature at the exhaust valve opening was decreased after the hydrogen addition. The addition of hydrogen contributed to the dropped hydrocarbon and carbon monoxide. However, nitrogen oxides were slightly raised after the hydrogen enrichment. [ABSTRACT FROM AUTHOR]

This paper presents the experimental determination of the ZIP coefficients model to represent (static) modern loads under varying voltage conditions. ZIP are the coefficients of a load model comprised of constant impedance Z, constant current I, and constant power P loads. A ZIP coefficient load model is used to represent power consumed by a load as a function of voltage. A series of surveys was performed on typical residential, commercial, and industrial customers in New York City. Household appliances and industrial equipment found in the different locations were tested in the laboratory by varying the voltage from 1.1-p.u. voltage to 0 and back to 1.1 pu in steps of 3 V to obtain the individual P–V, Q–V, and I –V characteristics. Customer load tables were built using seasonal factors and duty cycles to form weighted contributions for each device in every customer class. The loads found in several residential classes were assembled and tested in the lab. It was found that modern appliances behave quite differently than older appliances even from only 10 years back. Models of the different customer classes were validated against actual recordings of load variations under voltage reduction. [ABSTRACT FROM AUTHOR]

This paper presents the performance of homopolar inductor alternator (HIA) with diode-bridge rectifier and capacitive load. According to the conduction and commutation rules, all the operational modes included in the bridge rectified capacitive load are considered. A simplified average-value mathematical model is established; furthermore, we derive the load characteristic under every operation mode. Using the fundamental machine differential equations and the connecting characteristics between alternator and rectifier, we establish a port-network state model of the system. The performance of the HIA with bridge rectifier and capacitive load can be predicted from charging current, commutating angle, and given parameters of the alternator. Theoretical results are compared with the simulation results obtained from numerical procedure. [ABSTRACT FROM PUBLISHER]

A dynamics model of herringbone planet train with double teeth coupling is established based on the vibration theory of the concentrated parameter. The mesh stiffness formula of the helical gear is introduced to calculate the time-varying mesh stiffness of the herringbone teeth in the way of stiffness parallel of two helical gears. The relationship curves between the mesh stiffness of the internal and external meshes and the dynamic load coefficients of the internal and external meshes are obtained by solving the dynamic equation, and the impact of the mesh stiffness of the internal and external meshes on the dynamics load characteristics of the train is analyzed. The research results show that the dynamic load coefficients of the internal and external meshes increase with the average components of the mesh stiffness of internal and external meshes without regard to the resonance, respectively. The impact of the alternate component of the mesh stiffness of the internal and external meshes on the dynamic load coefficients is much less. Because of smooth operation and small vibration of the herringbone tooth, it is feasible that the average component of the mesh stiffness represents the mesh stiffness for the calculation of dynamic load coefficient of herringbone planetary train, when the required accuracy is not too high. [ABSTRACT FROM AUTHOR]

Distributed generators are acquiring more attention in power systems because they can avoid distribution and transmission upgrade requirements and improve power quality issues. Islanding is one of the problems that arise with integrating these resources into the distribution system. In this article, a novel hybrid islanding detection technique is proposed which uses average rate of voltage change and capacitor bank tap switching. The proposed method is tested on a real system and different load characteristics with different dependence coefficients to voltage and frequency are studied. The power system is perturbed only when the method suspects that islanding has occurred. The proposed method could detect islanding conditions with very small power mismatches in them. [ABSTRACT FROM AUTHOR]

According to the actual load suffered by a servo mechanism in a large launch vehicle, a comprehensive load simulation system was presented, which could simulate the inertia, elastic, friction and constant loads. The inertia load, elastic load and flexible assembling base of servo mechanism were simulated by the mechanical structures, and the friction load and constant load were simulated using a hydraulic system. A complete mathematical model was constructed by modeling the servo mechanism, its flexible structure and the loading hydraulic system. It is shown that this system can reproduce the load characteristics of the servo mechanism in actual situation, and the redundant force of the loading system is suppressed effectively. A load simulation system was developed for simulation of the loads and resonant characteristics, which provides the necessary fundamental facilities for ground test and further research of servo mechanisms. [ABSTRACT FROM AUTHOR]

The new principle of the organisation of working process of the combined supercharging system of transport diesel with the Cascade Pressure Exchanger (CPE) has been described. It allows considerably to raise level of forcing of the engine by supercharging at the expense of expansion of effective air supply area and coolings of supercharging air to temperature below an ambient. Substantive postulates of imitating model of work of combined engine(CICE) have been stated. Some results of calculation-experimental investigations of supercharging system of the engine 6ЧH12/14 have been given. It confirms the possibility of the essential improvement tractive and fuel-economic factors of the transport installations in broad range of the working conditions. [ABSTRACT FROM AUTHOR]

In China, national interconnected power system is a necessary trend for the development of electric power systems. Due to the time lag and temperature difference in different areas, the peak load discrepancy will influence the ratio of the regular components to stochastic components of system loads when power systems in different areas are connected. The power spectral densities of the regular loads and the stochastic ones were analyzed and compared in this paper, and how the load change works on the frequency regulation was also described with illustrations. The conclusion emphasized that primary frequency regulation is still relatively significant to the security of operating a huge interconnected power system, even if the system frequency could be controlled well through secondary regulation. [Copyright &y& Elsevier]

• Cluster model considering both load pattern and load composition is proposed. • A two-step algorithm is proposed to solve multi-objective cluster model effectively. • New algorithm reduces the chance of local optima when clustering a compound data case. • Seasonal load characteristics changes of substations are analyzed. • Substations share the similar load patterns may have different load composition. Extracting and analyzing abundant and accurate load characteristics of electricity distribution substations is the basis of works for load modeling. Substation load consists of a variety of subordinate loads with varied characteristics. Therefore, we propose a multi-objective clustering model taking both substation load pattern and load composition into consideration to cluster substations precisely. We propose a two-step algorithm called correct-cluster algorithm. We first cluster substations according to their load patterns. Then a new method is provided to correct these clustering results according to composition proportion of loads attached to these substations. The new method performs well in completing a multi-objective cluster in the test and practical cases. It is effective to prevent the result from falling into the local optimum, and it also achieves clustering results with more details. 39 substations with 19,407 users are taken as a sample in the practical case, where we use this method to analyze the load characteristics of substations in different seasons. Clusters of substations with similar load patterns and similar subordinate loads are formed, compared and analyzed. According to the cluster results, unusual substations share similar load patterns and diverse subordinate load composition proportions are also found and analyzed, which should be considered in future works about substation load modeling. [ABSTRACT FROM AUTHOR]