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In this study, the simultaneous effect of fluid pressure, vacuum pressure, and fluid temperature in the microfiltration process of tomato juice was investigated. For this purpose, a microfiltration device with a ceramic filter under pressure-vacuum combination was developed. Next, the effects of the device variables were investigated and optimised in the tomato juice microfiltration process. The results showed the statistically significant effects of fluid pressure, vacuum pressure, and fluid temperature on permeate flux response and total energy consumption. Also, they showed the effects of fluid pressure and fluid temperature on the response variables of lycopene and vitamin C content of tomato juice microfiltration. The optimal conditions of the microfiltration process of tomato juice were achieved at a fluid pressure of 200 kPa, the vacuum pressure of 5 kPa, and fluid temperature of 26 °C with a desirability index of 0.967. Under the optimal conditions, values of response variables including permeate flux, total energy consumption, lycopene, and vitamin C content of tomato juice filter were 215.09 × 10−6m3m−2s−1, 0.044 kWh, 2.42 mg100 g−1, and 13.21 mg 100 g−1, respectively. Overall, this type of tomato juice microfiltration, in addition to preserving the valuable nutrients of tomato juice, can cause high permeate flux and low process energy consumption.

After the completion of multi-stage fracturing operation, the fluid pressure in artificial fracture network continues to decrease, resulting in the closure of fracture and the variation of local induced stress field. This process can also lead to the variation of fracture propagation pattern in the subsequent fracturing stages. To better guide fracturing design, the time effect of stress field was researched. A numerical method was used to solve the induced stress around a propped fracture, and analyze the influence of formation properties and treatment parameters on its change. Then, the characteristics of stress field with different closure times and its influence on subsequent fracture were investigated. Finally, the evolution of the stress field in two stimulated wells was analyzed using the instantaneous shut-in pressure. The results show that the original horizontal stress difference, fluid pressure in fracture, fracture length, fracture angle, and amount of proppant have significant effects on the variation of induced stress field. The stress field of formation with undeveloped natural fractures decreases quickly with the rapid closure of hydraulic fractures due to the rapid drop in fluid pressure, but the stress field remains relatively constant after the fracture is fully propped. For formation with developed low angle natural fractures, the stimulated stage promotes subsequent fracture propagation and improves fracturing efficiency. The fluid pressure declined slowly and is non-uniformly distributed during the closure of the complex fracture network. Therefore, the magnitude and scope of the induced stress vary unevenly with the closure time, and there is a reasonable treatment time to form complex fractures during hydraulic fracturing. This study provides new insights into fracturing operation.

Wound closure with surgical sutures is a critical challenge for flexible endoscopic surgeries. Substantial efforts have been introduced to develop functional and smart surgical sutures to either monitor wound conditions or ease the complexity of knot tying. Although research interests in smart sutures by soft robotic technologies have emerged for years, it is challenging to develop a soft robotic structure that possesses a similar physical structure as conventional sutures while offering a self-tightening knot or anchor to close the wound. This paper introduces a new concept of smart sutures that can be programmed to achieve desired and uniform tension distribution while offering self-tightening knots or automatically deploying secured anchors. The core technology is a soft hydraulic artificial muscle that can be elongated and contracted under applied fluid pressure. Each suture is equipped with a pressure locking mechanism to hold its temporary elongated state and to induce self-shrinking ability. The puncturing and holding force for the smart sutures with anchors are examined. Ex-vivo experiments on fresh porcine stomach and colon demonstrate the usefulness of the new smart sutures. The new approaches are expected to pave the way for the further development of smart sutures that will benefit research, training, and commercialization in the surgical field.

The metavolcanics of Chitradurga region host numerous shallow crustal veins and fractures and faults of multiple orientations. Several high and low Pf cycles have been recorded in the region, leading to the reactivation of most of the pre-existing fractures for high Pf and selective reactivation of some well-oriented fractures under low Pf conditions. The pre-existing anisotropy (magnetic fabric) in the metavolcanics acted as the most prominent planar fabric for fracture propagation and vein emplacement under both conditions, thereby attaining maximum vein thickness. In this study, we emphasize the reactivation propensity of these pre-existing fracture planes under conditions of fluid pressure variation, related to the high and low Pf cycles. Multiple cycles of fluid-induced fracture reactivation make it difficult to quantify the maximum/minimum fluid pressure magnitudes. However, in this study we use the most appropriate fluid pressure magnitudes mathematically feasible for a shallow crustal depth of ∼2.4 km. We determine the changes in the reactivation potential with states of stress for the respective fracture orientations under both high and low Pf conditions. Dependence of fluid pressure variation on the opening angle of the fractures is also monitored. Finally, we comment on the failure mode and deformation behaviour of the fractures within the prevailing stress field inducing volumetric changes at the time of deformation. We find that deformation behaviour is directly related to the dip of the fracture planes.

The study aims to assess the significance of negative pressure therapy in the treatment of surgical wounds and using the ANSYS simulation software for fluid dynamics calculation will give us the possibility to determine the fluid flow dynamics inside the vacuum kit during its use. Material and methods: To predict the speed, pressure and temperature of the fluid inside a vacuum kit, we used numerical modeling, using the finite element method, of the gas fluid flow phenomenon. Results: The pressure of the liquid fluid is higher in the area of contact with the wound, compared to the pressure of the liquid fluid in the outlet area of the capillary tube, accentuating with increasing pressure applied to the end of the tube. 32% of the fluid pressure at the interface between the sponge and the wound. Conclusions: The rate of pressure transmission inside the sponge is variable favoring the appearance of ischemia areas on contact with the wound.

In the process of gas charging and discharging of gas cylinder, the fluid pressure fluctuates causing fretting wear of rubber sealing ring, which affects the sealing performance. The model of O-ring that installed at the mouth of the gas cylinder was established to study the fretting wear in the static seal. Effects of fluid pressure, compression ratio, friction coefficient and temperature on the fretting wear of the O-ring were considered. The results show that the fretting wear of O-ring can be divided into non-contact region, slip region and sticky region. In the static seal, the compression ratio and friction coefficient are the main factors affecting the fretting wear. The sealing performance is greatly influenced on the compression ratio and it is less affected by the temperature. The junction of slip region and sticky region has the greatest probability of seal failure.

Plugging upper and lower tips of hydraulic fracture by forming artificial barrier with diverting agent is as an effective method to prevent hydraulic fracture height from extending excessively. This work, obtained the transient analytical solutions of both fluid pressure decrement generated by artificial barrier (Δp) and equivalent permeability between artificial barrier and reservoir (K) at different positions of hydraulic fracture tips, clarifies parameters that affect the plugging effect of diverting agent on the tips. Seepage velocity that changes with plugging time (t) and maximum seepage distance were acquired by plugging experiments and were used to calculated Δp − t curves and K − t curves. It indicates that the variation rate of Δp and K changes from fast to slow until reaching a balance. However, for different positions of the tips, the time taken by Δp and K to reach balance is different. The diverting agent is suitable for hydraulic fracture beginning plugging when its floating or sinking effect appears relatively obvious and its horizontal migration effect is relatively weak. But if on the contrary, the agent is suitable for the ending plugging. When diverting agent concentration (λ) is lower, the effect of shortening time to complete plugging is more obvious by increasing λ, but the effect is weak when λ is higher because of the excessive accretion. This work has been successfully applied to an oilfield, which increased the production by 68.5% in a month and achieved directional plugging in hydraulic fracture.

Shoe wear is a major contributor to slip risk. Knowledge of the impact of shoe design features on wear progression and its impact on friction performance is emerging. This study investigated the ef...

The hip suction seal plays a key role in distractive stability and maintenance of intra-articular fluid pressure of the hip. Preservation of the suction seal relies on the acetabular labrum and the congruence between the labrum and the femoral head−neck junction. During the treatment of cam-type impingement, iatrogenic over-resection in the femoral head−neck junction or labrum deficiency can cause loss of this suction seal. In this technical note, we describe a remplissage procedure performed in addition to labral reconstruction in a patient with loss of the suction seal due to a dysfunctional labrum and previous over-resection of a cam deformity., Technique Video Video 1 This video describes the key aspects of a labral reconstruction and remplissage technique correlated with dynamic hip examination to restore suction seal in revision hip arthroscopy of a left hip. According to preoperative examination and imaging of a patient with previous hip arthroscopy, over-resection in the anterior part of femoral head−neck junction and a dysfunctional labrum are detected. After these findings are confirmed with diagnostic arthroscopy and an intraoperative dynamic hip examination, labral reconstruction and the remplissage procedure are planned. Both procedures are performed using the kite technique, with the graft prepared from the same semitendinosus allograft in accordance with the defect size. In the labral reconstruction procedure with the defect between 11 and 2 o’clock, the anchors at the 11 and 12 o’clock positions are placed through the anterolateral portal, whereas the anchors at the 1 and 2 o’clock positions are placed through the distal anterolateral accessory (DALA) portal. A proximal modified mid-anterior portal is created to prevent suture tangling during labral reconstruction. During the remplissage procedure, anchors are placed through the DALA portal while viewing from modified mid-anterior portal (mMAP). A mid-body anchor is placed in line with the convexity of the femoral head and acetabulum by using same portal configuration. After remplissage and labral reconstruction, dynamic hip examination is performed to evaluate the reestablished suction seal in the joint while viewing through the mMAP. Finally, the capsule is closed.

The aim of this study was to develop and present a teaching activity based on the integration of conceptual change methods consisting of concept cartoon, Prediction-Observation-Explanation (POE) technique, analogy and conceptual change text into the 5E model in order to remedy misconceptions about fluid pressure in the 8th grade of secondary school. Concept cartoon, TGA technique, analogy and conceptual change texts developed for this purpose were placed in a worksheet according to the 5E model. The purpose of developing the worksheet is to enable the teacher and the student to follow the lesson more easily. This study has remained at the theoretical level and has not been applied and tested to be effective in remedying misconceptions. Evaluation of the effectiveness of the worksheets developed in this study may be the subject of another research. It is believed that the worksheets enriched by the integration of different conceptual change methods developed within the scope of the research into the 5E model will be a resource for researchers and teachers in this field., Bu çalışmanın amacı ortaokul 8. Sınıf sıvı basıncı konusunda kavram yanılgılarının giderilmesine yönelik olarak kavram karikatürü, Tahmin-Gözlem-Açıklama (TGA) tekniği, analoji ve kavramsal değişim metninden oluşan kavramsal değişim metotlarının 5E modeline entegrasyonuna dayalı bir öğretim etkinliği geliştirmek ve sunmaktır. Bu amaç doğrultusunda geliştirilen kavram karikatürü, TGA tekniği, analoji ve kavramsal değişim metinleri bir çalışma yaprağında 5E modeline göre yerleştirilmiştir. Çalışma yaprağı geliştirilmesindeki amaç öğretmenin ve öğrencinin dersi daha kolay takip edebilmesini sağlamaktır. Bu çalışma teorik düzeyde kalmış olup uygulanıp kavram yanılgılarını giderme konusunda etkililiği test edilmemiştir. Bu araştırmada geliştirilen çalışma yapraklarının etkililiğinin değerlendirilmesi bir başka araştırmanın konusu olabilir. Araştırma kapsamında geliştirilen farklı kavramsal değişim metotlarının 5E modeline entegrasyonu ile zenginleştirilen çalışma yapraklarının bu alanda araştırma yapanlara ve öğretmenlere kaynak oluşturacağına inanılmaktadır.

There is growing concern about seismicity triggered by human activities, whereby small increases in stress bring tectonically loaded faults to failure. Examples of such activities include mining, impoundment of water, stimulation of geothermal fields, extraction of hydrocarbons and water, and the injection of water, CO2 and methane into subsurface reservoirs1. In the absence of sufficient information to understand and control the processes that trigger earthquakes, authorities have set up empirical regulatory monitoring-based frameworks with varying degrees of success2,3. Field experiments in the early 1970s at the Rangely, Colorado (USA) oil field4 suggested that seismicity might be turned on or off by cycling subsurface fluid pressure above or below a threshold. Here we report the development, testing and implementation of a multidisciplinary methodology for managing triggered seismicity using comprehensive and detailed information about the subsurface to calibrate geomechanical and earthquake source physics models. We then validate these models by comparing their predictions to subsequent observations made after calibration. We use our approach in the Val d’Agri oil field in seismically active southern Italy, demonstrating the successful management of triggered seismicity using a process-based method applied to a producing hydrocarbon field. Applying our approach elsewhere could help to manage and mitigate triggered seismicity. A multidisciplinary method for managing triggered seismicity is developed using detailed subsurface information to calibrate geomechanical and earthquake source physics models, and is applied to the Val d’Agri oil field in seismically active southern Italy.

The purpose of this study is presenting a new method for bending metal micro-tubes in a critical bending ratio. At first, using the fluid pressure and bending die in the bending ratio of 1.6, the micro-tube has been bent, which is caused wrinkling on the intrados of the micro-tube. Then, using a micro-wire mandrel, a new method for micro-tube bending has been proposed. Two parameters of micro-wire clearance and micro-wire arrangements have been investigated to generalize this method. The results have shown that the clearance of micro-wire with micro-tube should not be less than 50 μm because it will not be possible to insert micro-wire into the micro-tube. Also, the arrangement that has less clearance will have less cross-section distortion because they cause more filling within the micro-tube. In general, the results have shown that micro-tube bending with micro-wire mandrel did not have defects such as wrinkling and rupture. It also allows the micro-tube to bend at room temperature in a critical bending ratio.

Experiments to characterize the constant-rate gas depleted production behavior in core samples were performed to study the areal gas flowing mechanism of a high-pressure low-permeability heterogeneous gas reservoir, including a newly designed long-core experiment on areal heterogeneity constant-rate gas depleted production considering fracturing. In the experiments, the fluid pressure increased up to 45 MPa, and the cores of the near-wellbore high permeability area before and after fracturing and the cores of the low permeability non fractured area were connected in series to simulate the gas flowing process of the dual-area composite gas reservoir. When the irreducible water saturation is considered, the gas permeability in a high permeability area cater fracturing increased threefold. Experimental results indicated that the pressure difference in the near-wellbore high permeability area decreased rapidly after fracturing and increased in the low permeability area. The recovery:factor of each area increased titter fracturing. Fracturing could have a significant effect on increasing the recovery factor when the average permeability is relatively low. The greater the gas rate, the higher is the built-up pressure alter shut-in. Fracturing in the near-wellbore area may cause a significant decrease in the shut-in built-up pressure value.

A new generation of fluid pressure forming technology has been developed for the three typical structures of tubes, sheets, and shells, and hard-to-deform material components that are urgently needed for aerospace, aircraft, automobile, and high-speed train industries. In this paper, an overall review is introduced on the state of the art in fundamentals and processes for lower-pressure hydroforming of tubular components, double-sided pressure hydroforming of sheet components, die-less hydroforming of ellipsoidal shells, and dual hardening hot medium forming of hard-to-deform materials. Particular attention is paid to deformation behavior, stress state adjustment, defect prevention, and typical applications. In addition, future development directions of fluid pressure forming technology are discussed, including hyper lower-loading forming for ultra-large non-uniform components, precision forming for intermetallic compound and high-entropy alloy components, intelligent process and equipment, and precise finite element simulation of inhomogeneous and strong anisotropic thin shells.

By evaluating nozzle wear and predicting its dynamics, it is possible to determine and use the required operation modes of water jet devices, considering the minimum fluid pressure at which the specified cutting parameters (surface quality, slot depth) cannot be longer ensured, and, thus, determine the time of guaranteed compliance with cutting conditions and ensure timely replacement of nozzles.

The devices of heat sink plays vital role in effective heat transfer capability and flow patterns in central processing units (CPUs). These sinks are used to increase the surface area exposed to the surrounding fluid and in application which requires the surface to be within a certain temperature range. In order to achieve by attaching the heat sinks to the surface (says, a microprocessor chip) and the heat is transferred from the surface to the surrounding fluid air. In this present work describes the experimental investigation of heat sink made up of Al2024 alloys and variation of 20%, 30% and 40% copper compositions. In order to enhance the heat transfer with consideration of following physical parameters such as velocity of air, pressure of fluid and surface temperature. This result indicates the surface temperature of fluid increases with Al-40Cu composition compared to other combinations. Furthermore, the maximum fluid pressure withstands up-to 500 MPa at entry section (12 m/s) and minimum pressure achieved at 100 MPa in exit section of 6 m/s.

In hydrostatic forming, technological parameters have a significant influence on the thin shell product formation. One of the most important factors is the forming liquid pressure. This pressure exerts directly on the workpiece, pulling the workpiece closely to the die's profile. Therefore, this parameter should be kept large enough for shaping the product with the required shape and size. In practice, however, it is very difficult to achieve and maintain the high value of this parameter. In addition, it is also necessary to set up a mathematical model of this parameter to support the calculation and control. This paper has suggested a simple solution for maintaining fluid pressure during forming. The solution has been applied into the experimental system. Using this system to investigate forming liquid pressure parameter, the paper has given a suitable mathematical model when shaping cylindrical details from sheet metal. The results of the study contribute to data in die design, parameter calculation and control as well as forming process stabilization in hydrostatic forming for sheet metal.

In this study, we investigate the effects of the power-law index and permeability parameter on the deformation of soft tissue (articular cartilage) which is bathed in the non-Newtonian fluid under stress-relaxation in compression. Ramp displacement is imposed on the surface of hydrated soft tissue. Deformation of the tissue and the fluid pressure is examined for the fast and slow rate of compression. We have employed a linear biphasic mixture theory to develop a mathematical model for compressive stress-relaxation behavior of articular cartilage for non-Newtonian flow. Numerical results indicate that shear-thinning fluids induce less solid deformation and exhibit more fluid pressure as compared to shear-thickening fluids for fast and slow rate of compression. The results also show that linear permeability induces more deformation as compared to strain-dependent nonlinear permeability due to viscoelastic nature of articular cartilage.

The helical grooved seal, which is a non-contact sealing device using the viscosity of the fluid, prevents leakage by reducing fluid pressure according to the shapes of the rotor and stator. It has been widely adopted to turbomachinery because no wear deliveries high efficiency, unlike to the existing contact sealing device. In this study, parametric study was performed by CFD analysis, considering helical grooved seal shape: ratio of groove width and land width (Wratio), helical angle (β) and groove depth (d). Based on the leakage characteristics analyzed through CFD results, improved seal shape of the helical grooved seal to reduce leakage was suggested.

Pipeline fittings with ferrules are applied to connect sections of hydraulic pipelines in aircraft, and their reliability and stability are essential. This paper aims at investigating the influence of internal fluid on the sealing characteristics of pipeline fittings by employing the multiscale model. Changes in the sealing characteristics induced by the fluid pressure switch are studied, and the assembly method under the internal fluid is also explored. The calculated results show that the multiscale model can accurately reflect the changes in the sealing area, and the high-pressure fluid can enhance the sealing reliability. Compared with the contact area, the fluid pressure exerts a greater influence on the change in the area of the high-stress zone. Furthermore, the unrestored sealing area enlarges with the increased maximum fluid pressure, and the change in the area of the high-stress zone is significantly larger than that in the contact area. Moreover, the optimum assembly position of ferrule decreases with the increase in fluid pressure, thus achieving the excellent sealing characteristics.

This is the peer reviewed version of the following article: Lai, J., Chen, Y., Gu, Y., Batty, C. and Wan, J.W. (2020), Fast and Scalable Solvers for the Fluid Pressure Equations with Separating Solid Boundary Conditions. Computer Graphics Forum, 39: 23-33., which has been published in final form at https://doi.org/10.1111/cgf.13909. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

Involving the fluid-particle hydrodynamic process and hydraulically created fracture network, fracturing-fluid flowback in hydraulically fractured shale wells is a complex transport behavior. However, there is limited research on investigating the influence of proppant transport on the fracturing-fluid flowback behavior and flowback data analysis. In this paper, a flowback model is developed to simulate the flowback behaviors of the carrying fluid and proppant from the recompacted fracture system in shale wells. The development of fluid pressure and proppant concentration profiles of the fractured shale well are presented. The fluid and proppant fluxes among the hydraulic primary fracture and the induced fracture are also calculated. The influences of proppant consideration or not, proppant density, proppant size, fracturing-fluid viscosity, and fracturing-fluid density on the flowback behavior are investigated. The simulation results are useful for fracturing-fluid optimization in the design phase. Finally, two field cases from the Longmaxi Formation, Southern Sichuan Basin, China are used for matching the actual flowback data with the model results. The results prove that the proppant transport has influence on the flowback behavior to some degree and should be considered in the flowback model for a rather elaborate flowback analysis and post-treatment fracture evaluation.

This paper presents a novel method to determine the flow rate and fluid resistance of membrane-type restrictors. The coupled fluid pressure and membrane deformation is solved utilizing a fluid and structure interaction algorithm. The arbitrary boundary condition of a membrane is properly handled by adding the displacement springs and torsion springs to the boundary nodes of the membrane, and the finite element method is used to calculate the membrane deformation. Three different methods are studied using several case studies: the arbitrary boundary method, the large deformation method, and the traditional method. The results are compared with the experimental data available in the literature. It has been found that among all three methods, the arbitrary boundary method offers the best results. The membrane deformations show a nonlinear relationship with different supply pressures. The results reveal the boundary condition of the membrane is not a fixed boundary or a simply supported boundary; it is an arbitrary boundary condition, which varies with respect to the supply pressure. By taking the statistical model into consideration in the design process, the proposed arbitrary boundary condition method offers the potential to accurately calculate the flow rate and improve the reliability of the designs for membrane-type restrictors.

This study presents results of two series of permeameter experiments with 15 bentonites compacted to a bulk density of 1.6 g/cm3 before and after one-year contact with a model clay porewater with a salinity of 155 g/l. For four original bentonites, a double-peak pattern of swelling pressure evolution was revealed, which was observed previously only at much lower salinities. For 80 % of bentonites, swelling pressure and permeability were in the range of 0.8—4.8 MPa and 7·10−20—3·10−18 m2 (for original ones) as well as 0.5—2.2 MPa and 4·10−19—6·10−18 m² (for ones after one-year contact). A fl uid pressure surge of 12.6 MPa caused no hydraulic fracturing of original bentonites. This observation challenges the validity of threshold values of a few MPa for onset of hydraulic fracturing in compacted bentonites proposed earlier using an alternative experimental method. Yet, this fl uid pressure surge and a moderate one of 0.3 MPa caused a decrease of swelling pressure by up to 66 % — an effect, which need to be accounted for when designing and assessing the performance of bentonite-based barriers in a geological repository.

The bearing puller on the market today still has a way of working using a gripper with a screw working system. The time required is relatively long and can allow damage to the crankshaft during the bearing release process as well as reduced work performance of the crankshaft. This study aims to design a tool that works with a hydraulic system to release crankshaft motorbike bearings. This tool makes it easy for everyone to do the job of removing bearings. The outer bearing hydraulic tracker or puller uses the working principle of the lever that is pumped with calculated pressure and load and the fluid pressure on the tracker can be known ie at 1X the tracker pump requires 41 kg / cm2 fluid pressure, 2X fluid pressure tracker pump 45 kg / cm2 and 3X pump tracker requires 72 kg / cm2 fluid pressure. As well as the time needed to remove the crankshaft bearing motor especially on the A and B motorbike. To release the crankshaft bearing A motor takes 19.78 s and removing the crankshaft bearing the B motor takes 31.95 s.

Fluid fills intracellular, extracellular, and capillary spaces within muscle. During normal physiological activity, intramuscular fluid pressures develop as muscle exerts a portion of its developed force internally. These pressures, typically ranging between 10 and 250 mmHg, are rarely considered in mechanical models of muscle but have the potential to affect performance by influencing force and work produced during contraction. Here, we test a model of muscle structure in which intramuscular pressure directly influences contractile force. Using a pneumatic cuff, we pressurize muscle midcontraction at 260 mmHg and report the effect on isometric force. Pressurization reduced isometric force at short muscle lengths (e.g., −11.87% of P0 at 0.9 L0), increased force at long lengths (e.g., +3.08% of P0 at 1.25 L0), but had no effect at intermediate muscle lengths ∼1.1–1.15 L0. This variable response to pressurization was qualitatively mimicked by simple physical models of muscle morphology that displayed negative, positive, or neutral responses to pressurization depending on the orientation of reinforcing fibers representing extracellular matrix collagen. These findings show that pressurization can have immediate, significant effects on muscle contractile force and suggest that forces transmitted to the extracellular matrix via pressurized fluid may be important, but largely unacknowledged, determinants of muscle performance in vivo.

We re-evaluate the Raman spectroscopic quantification of the molar ratio and pressure for CH4–CO2 mixtures. Firstly, the Raman quantification factors of CH4 and CO2 increase with rising pressure at room temperature, indicating that Raman quantification of CH4/CO2 molar ratio can be applied to those fluid inclusions (FIs) with high internal pressure (i.e., > 15 MPa). Secondly, the v1(CH4) peak position shifts to lower wavenumber with increasing pressure at constant temperature, confirming that the v1(CH4) peak position can be used to calculate the fluid pressure. However, this method should be carefully calibrated before applying to FI analyses because large discrepancies exist among the reported v1(CH4)-P curves, especially in the high-pressure range. These calibrations are applied to CH4-rich FIs in quartz veins of the Silurian Longmaxi black shales in southern Sichuan Basin. The vapor phases of these FIs are mainly composed of CH4 and minor CO2, with CO2 molar fractions from 4.4% to 7.4%. The pressure of single-phase gas FI ranges from 103.65 to 128.35 MPa at room temperature, which is higher than previously reported. Thermodynamic calculations supported the presence of extremely high-pressure CH4-saturated fluid (218.03–256.82 MPa at 200 °C), which may be responsible for the expulsion of CH4 to adjacent reservoirs.

Summary Numerous technical papers have been published on the reservoir evaluation of tight sand gas in recent decades. It is believed that tight sand gas is characterized by low permeability, complex pore structure, abnormal pressure, and low gas saturation. Researchers have characterized tight gas in terms of, for example, statistics; and some of them are increasingly interested in the effect of fluid pressure and pore structure on gas saturation. However, there is still a lack of effective experimental and mechanism analysis. The focus of this paper is to investigate the effect of two factors on controlling the tight gas saturation. A method was proposed for determining the in-situ injection pressure of the DB 2 gas reservoir in the Kuqa area during the gas-accumulation period, and the result was 1.2 MPa. A polyetheretherketone carbon-fiber core holder (maximum temperature 180 °C, maximum confining pressure 30 MPa) was designed for the microcomputed-tomography (CT) simulation experiment. After that, four physical simulation experiments of different fluid pressures (0.1, 0.5, 1.5, and 5.0 MPa) were implemented using X-ray CT and the new core holder to study the effect of fluid pressure and pore structure on gas saturation. The results show that the fluid pressure and micropore connectivity are important factors for gas-saturation increase; the number of gas clusters (connected pores containing gas) increases with the increase of fluid pressure and the maximum volume of gas clusters increases with the increase of pore connectivity. The connected pores with the largest volume are an important source of gas-saturation contribution. The three types of modes (the blowing balloon mode, stitching mode, and composite mode) of microscopic gas-cluster formation are discussed. The blowing balloon mode is key to gas-saturation growth in the period of low fluid pressure or the early stage of the injection process. The stitching mode is key to gas-saturation growth in the period of high fluid pressure or the late stage of the injection process. The above research system investigates the quantitative control of fluid parameters (pressure) and reservoir parameters (pore structure) on gas saturation, which might change the situation where previous research was too focused on the pore-structure and fluid-pressure characterization, with a lack of quantitative control analysis of reservoir gas saturation. It provides a valuable reference and framework for the reader to conduct further quantitative research on tight gas saturation.

Currently, on-line leakage detection of sealed surfaces is being researched to improve detection accuracy. This study presents a new method of leakage detection by generating sounds with two crests at frequencies of 11.0 kHz and 32.7 kHz using specially designed cavity shaped whistles. The sound pressure levels (SPLs) that are generated were significantly greater than the pressure levels of the leakage jet noise at the sealing surface. In addition, the occurrence of the crests (11.0 kHz and 32.7 kHz) was independent of the leakage rate, leakage channel size, and sensor location. The experimental results showed that the leakage detection sensitivity and accuracy of the presented method exceeded those of the commercial acoustic emission (AE) method. The simulations revealed that the frequency crests resulted from strong fluid pressure oscillations and symbolic opposite radiation reactance of cavity shaped whistle. The proposed leakage detection method shows great potential in real industrial applications due to its anti-disturbance and good accuracy.

High‐pressure fluid injection in deep geo‐reservoirs can induce earthquakes. Recent observations suggest that cyclic injections might trigger less seismicity than monotonic injections. Here, we report triaxial laboratory experiments conducted on faulted quartz‐rich sandstone that provide new insight into the physics of fault‐fluid interactions subjected to cyclic fluid pressure variations. The experiments were performed at 30 and 45 MPa confining pressure, imposing constant or sinusoidal fluid pressure oscillations of amplitudes ranging from 0 to 8 MPa in addition to a far‐field constant loading rate (10‐4 and 10‐3 mm.s‐1). The results show that: (i) In agreement with the Mohr‐Coulomb theory, faults reactivate at the static friction criterion, which is generally reached at the maximum fluid pressure during oscillations. (ii) Oscillating fluid pressure perturbations promote seismic behaviour rather than aseismic slip, and (iii) increasing the oscillation's amplitude enhances the onset of seismic activity along the fault. We demonstrate that this behaviour is caused by slip rate variations resulting from the fluid pressure oscillations. Without fluid pressure oscillations, increasing the far‐field loading rate also promotes seismic activity. Our experiments demonstrate that the seismicity intensification due to cyclic fluid injections could be promoted at shallow depth, where confining pressure is relatively low, resulting in large strain rate perturbations.

Inferences have to be made about likely structures and their effects on fluid flow in a geothermal reservoir at the pre-drilling stage. Simple mechanical modelling, using reasonable ranges of values for rock properties, stresses and fluid pressures, is used here to predict the range of possible structures that are likely to exist in the sub-surface and that may be generated during stimulation of a potential geothermal reservoir. In particular, Mohr diagrams are used to show under what fluid pressures and stresses different types and orientations of fractures are likely to be reactivated or generated. The approach enables the effects of parameters to be modelled individually, and for the types and orientations of fractures to be considered. This modelling is useful for helping geoscientists consider, model, and predict the ranges of mechanical properties of rock, stresses, fluid pressures, and the resultant fractures that are likely to occur in the sub-surface. Here, the modelling is applied to folded and thrusted greywackes and slates, which are planned to be developed as an Enhanced Geothermal System beneath Göttingen.

The study of fluid inclusions is important for understanding various geologic processes involving geofluids. However, there are a number of problems that are frequently encountered in the study of fluid inclusions, especially by beginners, and many of these problems are critical for the validity of the fluid inclusion data and their interpretations. This paper discusses some of the most common problems and/or pitfalls, including those related to fluid inclusion petrography, metastability, fluid phase relationships, fluid temperature and pressure calculation and interpretation, bulk fluid inclusion analysis, and data presentation. A total of 16 problems, many of which have been discussed in the literature, are described and analyzed systematically. The causes of the problems, their potential impact on data quality and interpretation, as well as possible remediation or alleviation, are discussed.

Injection of CO2 for geologic carbon sequestration into deep sedimentary formations involves fluid pressure increases that engage hydromechanical processes that can cause seismicity by activation of existing faults. In this work, we use a coupled multiphase fluid flow and geomechanical simulator to model spatiotemporal fluid pressure and stress changes in order to study the poroelastic effect of CO2 injection on faults in crystalline basement rock below the injection zone. The seismicity rate along features interpreted to be basement faults is modeled using Dieterich's rate-and-state earthquake nucleation model. The methodology is applied to microseismicity detected during CO2 injection into the Mount Simon formation during the Illinois Basin—Decatur Project. The modeling accurately captures an observed reduction in seismicity rate when the injection in the second well was into a slightly shallower zone above the base of the Mount Simon formation. Moreover, the modeling shows that it is important to consider poroelastic stress changes, in addition to fluid pressure changes for accurately modeling of the observed seismicity rate.

Identifying and monitoring the presence of pressurized magma beneath volcanoes allows for improved understanding of internal dynamics and prediction of eruptions. Here we show with time-repeated tomography clear evidence that fresh melts accumulate since 2019 in three reservoirs located at different depths in the central feeding system. In these three volumes, we observe a significant reduction of seismic wave velocity, an anomaly that has endured for almost two years. Reservoir re-pressurization induced seismicity clusters around the pressurized volumes within high fluid pressure compartments. This indicated a sharp change in volcano behavior, with re-pressurization of the central system replacing two-decade-long, flank collapse-dominated dynamics. The volume where the velocities are altered is remarkable in size, suggesting the injection of new melt, and that erupted lava represents only a small percentage. Our findings suggest that ongoing volcanic recrudescence can persist. Melt accumulating in multiple reservoirs beneath Mt Etna could feed eruptions for decades to come, according to detailed seismic tomography modelling.

The output flow pulsation characteristics of the hydraulic pump due to the structural characteristics may cause pump source fluid pressure pulsation and even cause the equipment to vibrate, which will affect the life and working reliability of the equipment. Scholars have done a lot of theoretical and simulation analysis on the characteristics of fluid flow and pressure pulsation caused by the specific structure and structure of the plunger pump, but there are few comparisons and analyses of the simplified model of the plunger pump and the pressure pulsation characteristics with experiments. In this paper, AMESim software is utilized to establish a simplified model of one seven-plunger hydraulic pump, and simulate and analyze the pump source fluid pressure pulsation characteristics of different system load pressures at a constant speed. An experimental platform for testing pump fluid pressure pulsation was designed and built, and the actual measurement and simulation results of pump fluid pressure pulsation were compared and analyzed. The results show that the system simulation data is in good agreement with the measured data, which verifies the correctness of the simplified model of the plunger pump. At the same time, it is found that the fluid pressure pulsation of the pump source exhibits broadband and multi-harmonic characteristics. At a constant speed, as the load pressure of the hydraulic system increases, the pump source fluid pressure pulsation amplitude increases, the pressure pulsation rate decreases, and the impact on the fundamental frequency amplitude is the most significant. The research results can provide a theoretical basis for suppressing the pressure pulsation of the pump source fluid and reducing the vibration response of a hydraulic pipeline under the action of the pulsating harmonic excitation.

The purpose of this study is to investigate the role of the misalignment journal, caused by linear shaft misalignment, on the transient wear and mixed lubrication performances using a numerical model. In the numerical model, the transient geometry lubrication clearance considering the journal misalignment, the transient elastic deformation, and the transient wear depth of the bearing are incorporated to evaluate the transient film thickness during the wear process. The evolutions, under different external loads, of the wear depth of the bearing, wear-rate, elastic deformation of the bearing, film thickness, fluid pressure, and contact pressure are calculated by the numerical model. Furthermore, the calculated results of the misaligned journal bearing are compared with those of the aligned journal bearing. The results show that the distributions of the wear depth of the bearing, film pressure, and elastic deformation of the bearing are asymmetric along the axial direction and the peak values of them shift toward the back end when the journal misalignment is considered. The maximum wear depth, maximum fluid pressure, maximum contact pressure, and maximum bearing’s elastic deformation of the misaligned journal condition are significantly larger than those of the aligned journal condition.

Long-distance buried pipelines inescapably go through seismic fracture zones which makes the buried pipelines be easily influenced by the diastrophism. A strong and resilient pipe can withstand a certain degree of seismic oscillation. However, it is really difficult for buried pipelines to resist the permanent ground displacement caused by faulting and surface damage. Most of the existing studies only focus on the two-phase contact between pipeline and soil, and the mechanical behavior of the cross-fault pipeline under transportation condition has not been studied. In this article, ADINA finite element software is used to establish a pipe-soil-fluid three-phase coupling model based on fluid–structure interaction (FSI), and the influence of the parameters of pipe, fluid and fault on the mechanical properties of cross-fault buried gas pipeline is studied. The model considering the effect of fluid–structure interaction can effectively simulate the mechanical response of pipelines in the actual working condition. The work presented in this article can provide a reference for the design and safety of cross-fault buried pipeline conveying fluid.

The Yinggehai Basin is an important Cenozoic gas bearing basin in the South China Sea. With the gradual improvement of gas exploration and over-development in shallow layers, deep overpressured layers have become the main target for natural gas exploration. There are no large-scale faults in the strata above the Meishan Formation in the central depression, and hydraulic fracturing caused by overpressure in mudstone cap rocks is the key factor for the vertical differential distribution of gas. In this paper, based on the leak-off data, pore fluid pressure, and rock mechanics parameters, the Fault Analysis Seal Technology (FAST) method is used to analyze the hydraulic fracture risk of the main mudstones in the central depression. The results show that the blocks in the diapir zone have been subjected to hydraulic fracturing in the Huangliu cap rocks during the whole geological history, and the blocks in the slope zone which is a little distant from the diapirs has a lower overall risk of hydraulic fracture than the diapir zone. In geological history, the cap rocks in slope zone remained closed for a longer time than in diapir zone and being characterized by the hydraulic fracture risk decreases with the distance from the diapirs. These evaluation results are consistent with enrichment of natural gas, which accumulated in both the Yinggehai Formation and Huangliu Formation of the diapir zone, but it only accumulated in the the Huangliu Formations of the slope zone. The most reasonable explanation for the difference of the gas reservoir distribution is that the diapirs promote the development of hydraulic fractures: (1) diapirism transfers deep overpressure to shallow layers; (2) the small fault and fractures induced by diapir activities weakened the cap rock and reduced the critical condition for the natural hydraulic fractures. These effects make the diapir zone more prone to hydraulic fracturing, which are the fundamental reasons for the difference in gas enrichment between the diapir zone and the slope zone.

Aiming at the oscillation drag reduction tool that improves the extension limit of coiled tubing downhole operations, the fluid hammer equation of the oscillation drag reducer is established based on the fluid hammer effect. The fluid hammer equation is solved by the asymptotic method, and the distribution of fluid pressure and flow velocity in coiled tubing with oscillation drag reducers is obtained. At the same time, the axial force and radial force of the coiled tubing caused by the fluid hammer oscillator are calculated according to the momentum theorem. The radial force will change the normal contact force of the coiled tubing, which has a great influence on frictional drag. The results show that the fluid flowrate and pressure decrease stepwise from the oscillator position to the wellhead position, and the fluid flowrate and pressure will change abruptly during each valve opening and closing time. When the fluid passes through the oscillator, the unit mass fluid will generate an instantaneous axial tension due to the change in the fluid velocity, thereby converting the static friction into dynamic friction, which is conducive to the extend limit of coiled tubing.

Gasification of biomass in bubbling fluidized beds can be limited by accumulation of unconverted char particles during the process. The amount of unconverted biomass depends on the residence time of the fuel particles. This study demonstrates a method for measuring the biomass residence time over the conversion period at a given air flowrate and a given amount of biomass in a bubbling bed using the variation of bed temperature and fluid pressure recorded over time. The results show that biomass conversion is characterized by the devolatilization and extinction times. The two biomass residence times increase with decreasing air flowrate and increasing amount of biomass charged in the bed. The amount of unconverted char between the two characteristic times also increases with decreasing air flowrate and increasing biomass load. The total heat loss during the devolatilization is observed to increase with increasing air flowrate and amount of biomass in the bed. Correlations are proposed for predicting the mean biomass residence time, the amount of unconverted char particles and the devolatilization heat loss at a given operating condition. The results of this study can be used in determining the bubbling bed properties and solid circulation rate required to decongest the accumulated char particles in the bed.

This paper reports a comprehensive study of soft lubrication in a porous layer whose thickness ranges from 3.1 mm to 19.0 mm, using two experimental setups for different scales of porous media. We demonstrate that the lubrication theory for soft porous media (Feng and Weinbaum, J. Fluid Mech. 422, 282, 2000) is valid in describing the fluid pressurization, while the theory by Toll (Polym Eng Sci 38, 1337, 1998) is appropriate in predicting the solid phase lifting force. A new model is then developed for estimating the contribution of the fluid pressure to the total lift, which, along with extensive dimensional analysis, provides critical insights for the application of soft porous lubrication in industrial applications.

DOI nefunkční (6.11.2019) This paper describes the methodology by which it is possible to compare different tensile forces that are caused by the uneven distribution of loads in carrier ropes of lifts. In order to compare the applied tensile forces in a certain number of carrier ropes, it is possible to use the device called "rope hydraulic tension compensator", when, for example, building new elevators, changing carrier ropes during renovations or servicing existing lifts. The comparison of tensile forces in lift carrier ropes by the described device is based on the method of liquid pressure diffusion in a closed vessel. The rope hydraulic tension compensator consists of a number of structural parts, the main of which are double-acting hydraulic cylinders. The number of these cylinders is equal to the number of carrier ropes of the given lift. The pressure of the hydraulic fluid, which is supplied to the inner shell of individual hydraulic cylinders, controls the length of extension of individual piston rods of the hydraulic cylinders. The position of the piston in each of the hydraulic cylinders is directly proportional to the length of the extended piston rod, which corresponds to compression of the cylindrical coiled spring, above which the respective hydraulic cylinder is located. Different compressions of individual cylindrical springs exert different magnitude of tensile forces in suspension eye-bolts, into whose longitudinal axes the total load size is distributed unevenly. The paper also describes the description and hydraulic circuit diagram of a hydraulic power unit, which is used to control the piston positions of two-way hydraulic cylinders. Web of Science 13 3 37 31

This paper is concerned to develop a fluid pressure system for the control of artificial bladder urine discharge. The primary goal is to force the fluid into the space between the inner wall and the outer wall by using a pump in the artificial bladder having a double structure of inner and outer walls and to form the urine discharge pressure by the contraction of the bladder inner wall due to the movement of the fluid. The ANSYS_CFD analysis is used to confirm the delivery of fluid pressure in the artificial bladder model, and the ANSYS_FSI analysis is used to identify the deformation and internal pressure of the artificial bladder through the delivery of fluid pressure, and to identify the discharge of urine. As the design parameters of the modeling of the artificial bladder and the fluid flow field, the capacity of the flow field, and the pump pressure input value were selected.

This study analyzes the velocity and pressure incurred by protruding shapes installed within the inlet part of a pressurized membrane module during operation to determine the fluid flow distribution. In this paper, to find the flow distribution within a module, it investigates the velocity and pressure values at cross-sectional and outlet planes, and 9 sections classified on outlet plane using computational fluid dynamics. From the Reynolds number (Re), the fluid flow was estimated to be turbulent when the Re exceeded 4,000. In the vertical cross-sectional plane, shape 4 and 6 (round-type protrusion) showed the relatively high velocity of 0.535 m/s and 0.558 m/s, respectively, indicating a uniform flow distribution. From the velocity and pressure at the outlet, shape 4 also displayed a relatively uniform fluid velocity and pressure, indicating that fluid from the inlet rapidly and uniformly reached the outlet, however, from detailed data of velocity, pressure and flowrate obtained from 9 sections at the outlet, shape 6 revealed the low standard deviations for each section. Therefore, shape 6 was deemed to induce the ideal flow, since it maintained a uniform pressure, velocity and flowrate distribution.

Oilfield wastewater disposal causes fluid pressure transients that induce earthquakes. Here we show that, in addition to pressure transients related to pumping, there are pressure transients caused by density differences between the wastewater and host rock fluids. In northern Oklahoma, this effect caused earthquakes to migrate downward at ~0.5 km per year during a period of high-rate injections. Following substantial injection rate reductions, the downward earthquake migration rate slowed to ~0.1 km per year. Our model of this scenario shows that the density-driven pressure front migrates downward at comparable rates. This effect may locally increase fluid pressure below injection wells for 10+ years after substantial injection rate reductions. We also show that in north-central Oklahoma the relative proportion of high-magnitude earthquakes increases at 8+ km depth. Thus, our study implies that, following injection rate reductions, the frequency of high-magnitude earthquakes may decay more slowly than the overall earthquake rate., Oilfield wastewater is commonly discarded by pumping it into deep geologic formations, but this process is now known to cause earthquakes. Here, he authors show that high-density oilfield wastewater may sink deeper in the Earth’s crust than previously considered possible, thus increasing fluid pressure and inducing earthquakes for years after injection rates decline.

In this paper, we implement a finite volume method for approximating the pressure of fluid flowing within three dimensional fractures and formulate a scheme for computation of the fluid velocity and flux in the fractures. These are needed to couple with an existing fracture propagation code based on a displacement discontinuity method for simulation of hydraulic fracturing processes. Both of the methods discretise the fracture only, not its two surfaces. The pressure and velocity computed with the proposed numerical schemes are shown to qualitatively agree with analytic solutions for several cases of flow in planar annular fractures.

Stoneley waves induce fluid pressure gradients in a permeable formation surrounding the borehole. These gradients are equilibrated through pressure diffusion, that is to say, slow P-waves in the context of Biot’s poroelasticity theory. Because slow P-waves are strongly sensitive to the formation permeability, the Stoneley-slow P-wave interaction can be used to retrieve the formation permeability from the attenuation and dispersion of Stoneley waves. The accuracy of this established technique in high-permeability formations deteriorates when slow P-waves are not pure diffusion waves; hence, the permeability dependence is more complicated. This effect on Stoneley waves is captured by applying the Johnson-Koplik-Dashen dynamic permeability model. Their model depends on a viscous relaxation length. However, in the estimation of formation permeability from Stoneley waves, this parameter is typically not measured but is estimated from an empirical equation, wherein material properties and microstructural descriptors are lumped together. When the so-calculated relaxation length is erroneous, the inverted formation permeability from the Stoneley wave is not correct either. To overcome this limitation and to provide a versatile alternative, the dynamic permeability problem is reformulated within the viscosity-extended Biot framework. Its physical basis is the conversion scattering in random media from slow P- to slow S-waves. The correlation length of this so-called stochastic dynamic permeability model can be derived from pore-scale images, and it also captures the effect of pore interface roughness. This model is then combined with the simplified Biot-Rosenbaum model to predict Stoneley wave attenuation and dispersion. We have applied this hybrid model to interpret laboratory measurements for which the previously suggested choice of the viscous relaxation length does not provide an accurate prediction. The results indicate that the hybrid model can provide another approach to model Stoneley wave attenuation and dispersion across the entire frequency range.

A two-dimensional finite element analysis has been performed to investigate hydromechanical and conventional deep drawing processes. The effects of the fluid structure interaction on the material formability, the strain and the thickness distributions are investigated. Large plastic deformation is observed in the plank at the bottom and the corner of the punch. Plastic deformation distribution results show a difference between the hydromechanical deep drawing process and the conventional deep drawing which is due to the friction effect. This latter represents one of the major features of the hydromechanical deep drawing process. Concerning the formability of the blank, the obtained results show that the hydromechanical deep drawing process gives a better formability than the conventional deep drawing process.