Inlet Diameter Research Articles

Prediction and analysis on the effects of different inlet diameters of a hydrogen gas tank during fast fill using ANN by the neurofit technique

Prediction and analysis on the effects of different inlet diameters of a hydrogen gas tank during fast fill using ANN by the neurofit technique

The first record of larval <i>Crassostrea gigas</i> (Thunberg 1793) (Bivalvia, Ostreidae) from the Black Sea

Larvae of the oyster, Crassostrea gigas (Thunberg 1793) are being found in the plankton of the Black Sea for the first time. The studies were carried out in 2014–2023 along the Sevastopol coast. Samples were taken monthly with a Jeddy plankton net (inlet diameter 36 cm, mill gas mesh 135 µm). A water layer of 10–0 m was investigated. Live material was processed by total counting the larvae in the Bogorov chamber, using MBS-9 and Mikmed-5 light microscopes. Oyster larvae were recorded in August 2020 and observed in the plankton from the end of August to the beginning of October. They were also found in the waters at Miskhor, southern coast of Crimea in August 2023. The density of larvae amounted to 1–3 ind./m3. Larvae were found at the following water temperatures: minimum, 19.7 °C (September 2021), maximum, 26.6 °C (August 2022). In August, the larvae of C. gigas were at the stage of veliconch, their sizes ranging 275–340 mkm. The sizes of oyster larvae in September and October were 380 mkm, being already in the late stages of development. In the coastal waters of the northern part of the Black Sea, C. gigas larvae can settle on substrates from late August to mid-October.

Effect of Induced Wheel and Impeller Inlet Diameter on the Hydrodynamic Performance of High-speed Centrifugal Pumps

The high-speed centrifugal pump plays a crucial role in fields such as aerospace and petrochemical industries, owing to its characteristics of elevated rotational speed and high head. During high-speed operation, the centrifugal pump is prone to cavitation, which alters the fluid flow state within the pump, leading to vibrations, noise, and a sudden decrease in pump head and efficiency. Simultaneously, the collapse of cavitation bubbles generates impact pressure that can damage the pump's internal flow components, significantly reducing its operational lifespan and causing severe consequences. Moreover, under constant-flow conditions, the absolute and relative velocities of the fluid at the impeller inlet are functions of the suction pipe diameter. Therefore, there exists an optimal value for the impeller inlet diameter to enhance the centrifugal pump's resistance to cavitation. Similarly, the different geometric and structural parameters of the inducer also influence the hydraulic performance of the centrifugal pump. The focus of this study is on the external characteristics and internal flow patterns of an optimized high-speed centrifugal pump. In this paper, the entire flow field of the model pump is numerically simulated using ANSYS CFX software. The performance and overall flow field state of the high-speed centrifugal pump under different impeller configurations and inlet diameters are explored. The influence of blade wrap angle and inlet diameter on the high-speed centrifugal pump is revealed, providing a theoretical basis for subsequent optimal design.

Optimum Design of Cooling Structure for In-Wheel Motor Drive System

The high-efficient cooling structure is one of the key basic problems in the design of the highly integrated in-wheel motor (IWM) drive system. A 15 kW IWM drive system with the spiral cooling structure is taken as the research object in this article. First, the thermal characteristics under different conditions are analyzed based on the modeling and the heat source determination of the IWM drive system. Second, the highest temperature of insulation and permanent magnet and temperature difference of insulation are taken as optimization objectives. The inlet flow rate, the inlet and outlet diameters, the channel numbers, the channel height, and the channel ribs thickness of cooling structure are taken as optimization parameters to optimize based on the designed experiments, the multivariate linear regression equation and PSO method. Finally, the optimization results are verified by comparing the temperature field before and after optimization. The results show that the optimized structure can achieve better effect. The highest temperature of insulation, the highest temperature of permanent magnet and the temperature difference of insulation of IWM decreased by 9.27%, 9.52%, and 20.93%, respectively. This research work can provide some ideas and methods for the optimization design of cooling structure of IWM drive system.

Systemic investigation of pelvimetric profile in three strains of Deoni cattle

The present research work was designed to establish baseline data of the pelvimetric profile in Deoni Cattle. Deoni cattle (270) of three strains, i.e. Wannera, Balankya and Shevera were selected and divided into six age groups: Group I (12 to 24 months), II (25 to 36 months), III (37 to 48 months), IV (49 to 60 months), V (61 to 72 months) and VI (73 to 84 months) with 45 animals in each group. Body weight along with different pelvimetric parameters such as distance between two angles of haunch (A), distance between two ischial tuberosities (B), distance between level of croup and hip joint (C) and distance between tuber coxae and tuber ischia (D) were measured to determine the transverse and vertical diameter of pelvic inlet and outlet which were used to calculate pelvic area of inlet and outlet. The pelvic area values for both inlet and outlet showed highly significant differences within groups, but no significant difference was observed between the three strains of each group. From the results of the study, it can be concluded that the pelvic area of Deoni cattle increases with the age and it has significant positive correlation with the parity and body weight. Thus, pelvimetric profile can be used as a marker for selection of young Deoni heifers and cows for breeding purposes to lower dystocia incidences.

Design of alveolar biomimetic enhanced heat transfer structure for cylindrical lithium battery pack

Aiming to address the issue of thermal runaway in high energy density batteries during high charge and discharge rates, a heat management system for an alveolar-like honeycomb liquid-cooled power battery was designed. This system is inspired by the bionic concept of cell cooling in biological tissues, with cylindrical batteries serving as cells and cooling channels resembling blood vessels. The cooling system for a battery pack consisting of 24 cylindrical cells was designed and implemented. Numerical simulations were conducted to optimize and study the effects of inlet diameter, branch angle, flow rate, and spiral baffle on coolant flow uniformity and temperature distribution within the battery pack. The results indicate that as the inlet diameter of the fractal channel increases from 2 mm to 20 mm, the coolant flow uniformity improves and the pressure drop decreases. However, the influence of inlet diameter diminishes after reaching a certain limit. When the inlet diameter increases from 10 mm to 20 mm, the relative standard deviation of the velocity at the branch outlet decreases only slightly, from 0.9 % to 0.8 %. Increasing the branch angle from 30° to 75° leads to an increase in the relative standard deviation of velocity, from 0.79 % to 1.24 %. Incorporating a spiral baffle into the internal flow channel of honeycomb cooling significantly enhances temperature uniformity within the battery pack while reducing maximum temperature levels considerably. Furthermore, a smaller pitch for the spiral baffle yields better cooling performance for the immersed liquid cooling thermal management system. After optimization, the maximum temperature difference is only 1.27 °C across the surface of the battery pack, achieving a remarkable temperature uniformity level of just 0.11 %.

Numerical investigation of the impact of inlet and outlet ports of water jet impingement cooling modules

AbstractThe ever‐growing applications of high‐power chips have driven research efforts to enhance the performance of their active cooling modules. This study proposes a simple tweak of the cooling module's ports for lower thermal resistance. A dual‐inlet single‐outlet (CP2) jet impingement cold plate (JICP), a dual‐inlet dual‐outlet (CP3) JICP, and a single‐inlet dual‐outlet (CP4) JICP were assessed computationally and benchmarked against a single‐inlet single‐outlet JICP (CP1) at the same area ratio (AR) and average diameter (Davg) of inlet and outlet ports. The results show that the pressure losses inflate by up to 4.67 folds when using CP3 with AR = 5/3 and Davg = 3.0 mm. Yet, this design also shows the largest Nusselt number and the lowest outlet water temperature, module body temperature, average temperature of the target surface, and thermal resistance (0.07415 K/W). The thermal resistance is reduced by 34.13% using CP3 at AR = 3/5 and Davg = 6.0 mm. The temperature uniformity index was boosted to 97.5%. These enhancements are attributed to the shorter and symmetric flow path, the shorter residence time of water within the JICP, and the direct heat diffusion by the walls of the lower chamber.

Analysis on the Influence of Duct Casing Geometry on the Performance of a Ducted Fan

This paper aims to evaluate the influence of an electric ducted fan’s (EDF) geometry on its performance through parameter correlation analysis. Sample data was first built by generating new EDF models with varying duct casing geometries through optimal space-filling (OSF) sampling method. Afterwards, each model was numerically solved with computational fluid dynamics (CFD) analysis to obtain each model’s thrust, required power, and efficiency. It is found that the casing’s inlet lip diameter displays the greatest influence on the EDF’s total thrust, as the inlet diameter determines the casing’s surface area affected by the low-pressure region ahead of the rotating fan blades. Additionally, it is found that length of the casing’s exhaust lip affects the EDF’s efficiency, while the exhaust lip diameter displays the highest correlation with the fan’s required power.

Theory and Experiment of the Limiting Current in Impinging Jet Electrodes

Recently, flow cells with a confined impinging jet type have emerged as a promising hydrodynamic electrochemical setup for non-conventional square model electrodes that cannot be measured in the commonly used rotating disk electrode (RDE) setup1. Due to the complex hydrodynamic flow profiles, these flow cell types usually rely on computational fluid dynamics (CFD) simulations for the description of the local current density profiles and overall current-potential characteristics2. In this work, we present an advanced analytical model of the limiting current in confined impinging jet electrodes and validate the model with experimental data and corresponding CFD simulations.Around 350 parameter sets of the confined impinging jet electrode arrangement were analyzed by varying the inlet diameter (d), distance between inlet-nozzle and electrode (H), electrode radius (RIII), and volume flow rate (V0). Figure 1 shows the proposed analytical solution which separates the electrode into three different diffusion regions: (i) wall-tube region (blue rectangle), (ii) wall-jet region (green rectangle), and finally (iii) radial channel-flow region (orange rectangle). The approach allows predicting the limiting current characteristics for a broad variety of impinging jet electrodes, including the confined impinging jet electrode type. The flow line profiles obtained by CFD simulations are in excellent agreement with the analytically determined regimes with radii RI and RII and flow regime transitions. Very importantly, for the construction of ideal wall-tube electrodes the transition point RI can now be described by our analytical model in high accuracy and requires no more in-depth numerical or experimental studies3. We determined an average relative error over all parameter points compared to the numerical CFD simulations to be 7.8 %. In contrast, the analytical formula for free wall-jets4 to the entire electrode is in the range of 29 %. Furthermore, using a 3D-printed flow cell geometry (H = 0.7 mm; d = 0.5 mm) with the confined impinging jet type, the obtained experimental data confirm the here developed analytical model. The experimental data for different electrode radii (1 mm < R < 3 mm) using the ferrocyanide/ferricyanide redox pair ([Fe(CN)6]4-/[Fe(CN)6]3-) also show good agreement to the analytical model with an average deviation of 6 %.In summary, we have developed an analytical model that allows an accurate prediction of the limiting current for different geometries of the impinging jet electrode. Based on numerical and experimental approaches, our model shows an accuracy of below 10 %, which is very remarkable compared to the current models reported in the literature. The results of this study help to improve the design and construction of electrochemical flow cells based on this electrode type as an alternative to the classic RDE setup.

Experimental and numerical study on ferrohydrodynamic and magneto-convection of Fe3O4/water ferrofluid in a sudden expansion tube with dimpled fins

BackgroundThis study experimentally and numerically addresses magnetohydrodynamic forced convection including dimpled fins, Fe3O4/water ferrofluid, and DC magnetic field. In this research, focusing on the thermo-hydraulic performance improvement of a sudden expansion tube. It has been used different inlet diameters, dimple sizes, ferro nanoparticle concentrations, and magnetic field strengths to examine the heat transfer and fluid dynamics characteristics of the system. MethodsThe study consists of two parts, i) experimental and ii) numerical. Steady-state, incompressible, Newtonian flow were considered but chemical reaction, viscous dissipation, buoyancy, and radiative heat transfer were neglected in this study. On the other hand, numerical solutions were carried out for single-phase method. This study was first compared with the studies in the literature on the flow in a sudden expansion tube without dimpled fins and the error rate was found to be less than 10 %. In the analysis, dimpled fins with d=3, 5, and 7 mm at each P=15 mm (P/d=5.0, 3.0, and 2.14) have been used. As working fluid, Fe3O4/water ferrofluid with volume concentration of φ=1.0 % and 2.0 % have been analyzed. Additionally, DC magnetic fields, which strength of Ha=0.1, 0.3, 0.5, 1.1, 3.2, and 5.3 (B =0.01, 0.03, 0.05, 0.1, 0.3, and 0.5T), have been applied on the sudden expansion tube surface as external force. Significant findingsDimpled fins enhance the heat transfer by disrupting the boundary layer and forming secondary flows, while the ferrofluid increases the thermal conductivity and viscosity of the base fluid. Based on these explanations, dimpled fins increased the convective heat transfer rate at the rate of 96.0 % compared with smooth tube. In addition, Fe3O4/water ferrofluid with φ=2.0 % performed the highest performance and performance evaluation criteria increased by 8.5 %. The magnetic field also contributes to the heat transfer enhancement by inducing Lorentz force and mixing the flow. Excessive increasing of magnetic field strength adversely affected the system performance, and the highest performance evaluation criterion is acquired at Ha=3.2 by increasing 3.9 %. Compared with smooth tube, compound effect of dimpled fins, Fe3O4/water ferrofluid, and magnetic field improved the average Nusselt number and performance evaluation criterion at the rate of 279.8 % and 207.9 %, respectively.

Effects of Bony Pelvic and Prostate Dimensions on Surgical Difficulty of Robot-Assisted Radical Prostatectomy: An Original Study and Meta-analysis.

Due to the deep location of the prostate within the pelvic cavity, procedures of robot-assisted radical prostatectomy (RARP) might be challenged by the prostate size and the limited pelvic cavity space. This study aimed to investigate the roles of bony pelvic and prostate dimensions in RARP procedures by an original study coupled with a meta-analysis. In the original study, patients undergoing multiport RARP between 2021 and 2022 were consecutively assessed. The associations of anatomic features with operative time (OT), estimated blood loss (EBL), and positive surgical margin (PSM) were evaluated using linear and logistic regression analyses as well as restricted cubic spline (RCS) analysis. Based on machine-learning algorithms, this study established predictive models for surgical difficulty and interpreted the model using SHapley Additive exPlanation (SHAP). In the meta-analysis, three databases were searched for eligible studies. Quantitative syntheses were subsequently performed. Overall, 219 patients were enrolled in the original study. Prostate volume (PV) and the prostate volume-to-pelvic cavity index (PCI) ratio (PV-to-PCI ratio) were significantly associated with longer OT (P < 0.05). In the RCS models, U-shaped associations were observed between the prostate anteroposterior diameter (PAD) and OT, and between the prostate height (PH) and EBL, and an L-shaped association was observed between the anteroposterior diameter of the pelvic inlet (API) and EBL. The XGBoost model was superior to the logistic regression model in predicting prolonged OT. The meta-analysis demonstrated that greater PV was significantly associated with longer OT (β = 0.20; 95% confidence interval [CI] 0.12-0.27; odds ratio [OR] = 1.05; 95% CI 1.00-1.11), and a smaller PV could increase the risk of PSM (OR = 0.82; 95% CI 0.77-0.88). A large prostate within a narrow and deep pelvis might suggest increased surgical difficulty of RARP. The size of the pelvic inlet also had a great impact on RARP. For PAD and PH, there seemed to be an optimal range with the lowest surgical difficulty. Machine-learning models based on the XGBoost algorithm could be successfully applied to predict the surgical difficulty of RARP.

Effects of structure parameter and material property on thermal performance of on-board hydrogen storage tanks during fast refueling

As a power generation fuel, high-pressure hydrogen gas is widely used in transportation, and significantly contributed to development of hydrogen fuel cell electric vehicles. However, obvious temperature rise generated during fast refueling causes serious safety risk to reliable operation of fuel cell stacks. Therefore, it is necessary to conduct in-depth research on fast filling process. Based on safety reasons, the SAE J2601/ISO 15869 strictly regulates the maximum temperature limit of 85 °C in specifications for refueling hydrogen gas tanks. In this study, a 70 MPa, Type IV on-board hydrogen storage tank is adopted as the research object, and a 2-dimensional axisymmetric numerical model is established to study the temperature rise of the vapor within storage tanks during fast refueling. The Realizable k-ε turbulence model is employed to simulate high intensity turbulent fluctuation during fast filling. Considering the compressibility of vapor, the state of equation for real hydrogen gas is used by obtaining fluid thermodynamic properties from the National Institute of Standards and Technology database. Three groups of fast filling experiments are selected to validate the developed numerical model. The comparison result shows that the numerical model has good prediction ability on hydrogen fast refueling. The final mass average temperature differences between numerical results and experimental data are 2.6 K, 4.3 K, and 0.03 K, respectively. Based on the developed numerical model, the influences of structure parameters and material properties on the temperature rise of hydrogen storage tanks are investigated. The results indicate that the inlet diameter and wall thickness of the inner and outer layers of the storage tank have weaken impacts on the temperature rise during rapid charging, with the maximum temperature differences of 1.8 K, 0.74 K, and 0.54 K, respectively. Due to the influence of heat capacity, the material properties of different layers exhibit a similar variation trend. This work can deepen researchers' understanding of the temperature rise of on-board hydrogen storage tanks during fast filling, and provide technical references for the structural optimal design of tanks and rapid refueling at hydrogen stations.

Effect of inlet diameter on the flow structure and performance for aluminum-based water-jet engine

Abstract In this study, the flow field and performance for the aluminum based water ramjet was analyzed through numerical simulation. The time decrease in evaporation heat absorption process expands the range of aluminum/water combustion and increase the specific impulse. If the diameter of atomized water droplets from the primary inlet is large, the evaporation efficiency will be further reduced, which is not conducive to the further propagation of the reaction. However, if the diameter is small, the flow field temperature will be rapidly dropped due to rapid evaporation, and a large range of low-temperature areas will appear in the reaction area of the combustor. The diameter reduction of atomized water droplets from the secondary water inlet is conducive to the diffusion of the reaction area downstream, further and makes the combustion range be expanded. This effect is benefit for increasing the specific impulse and can reduce the temperature near the wall.

Improvement of sand-washing performance and internal flow field analysis of a novel downhole sand removal device

With the progression of many shale gas wells in the Sichuan-Chongqing region of China into the middle and late stages of exploitation, the problem of sand production in these wells is a primary factor influencing production. Failure to implement measures to remove sand from the gas wells will lead to a sharp decline in production after a certain period of exploitation. Moreover, As the amount of sand produced in the well increases, the production layer will be potentially buried by sand. To boost the production of shale gas wells in the Sichuan-Chongqing region and improve production efficiency, a novel downhole jet sand-washing device has been developed. Upon analyzing the device's overall structure, it is revealed that the device adopts a structural design integrating a jet pump with an efficient sand- washing nozzle, providing dual capabilities for jet sand- washing and sand conveying via negative pressure. To enhance the sand- washing and unblocking performance of the device, various sand- washing fluids and the structures of different sand- washing nozzles are compared for selection, aiming to elevate the device's sand- washing and unblocking performance from a macro perspective. Subsequently, drawing on simulation and internal flow field analysis of the device's sand- washing and unblocking process through CFD and the control variable method, it is ultimately found that the length diameter ratio of the cylindrical segment of the nozzle outlet, the outlet diameter, and the contraction angle of the nozzle greatly influence the device's sand- washing and unblocking performance. And the optimum ranges for the length-diameter ratio of the cylindrical segment of the nozzle outlet, the outlet diameter, the contraction angle of the nozzle, and the inlet diameter are 2 to 4, 6 mm to 10 mm, 12° to 16°, and 18 mm and 22 mm, respectively. The findings of the research not only provide new insights into existing sand removal processes but also offer a novel structure for current downhole sand removal devices and a specific range for the optimal size of the nozzle.

Could radiological parameters help to predict the failure of ureteral access sheath placement

To identify the radiological parameters which may help to predict the success of ureteral access sheath (UAS) placement during retrograde intrarenal surgery (RIRS).The study included 49 patients in whom failure ureteral access sheath placement in RIRS and 49 control group patients who were successfully placement between January 2023 and December 2023. The age, gender, body mass index (BMI), non-contrast computed tomography (NCCT), and kidney ureter bladder (KUB) radiographs were compared between the two groups. Measurements of the anteroposterior (ap) diameter of the pelvic inlet, anteroposterior diameter of the pelvic outlet, interspinous distance diameter were taken from non-contrast computed tomography (NCCT), while pelvic anteroposterior diameter and pelvic lateral diameter were measured from kidney ureter bladder (KUB) radiography. There were no significant differences between the groups in age, gender, body mass index, ap pelvic inlet diameter, ap pelvic outlet, and interspinous distance diameter. However, a statistically significant difference was found between the pelvic ap diameter and pelvic lateral diameter values measured on the KUB radiography. The values for pelvic ap diameter and pelvic lateral diameter measured in the KUB radiographs can be used to predict the likelihood of UAS passage during RIRC procedures. However, further studies with larger patient groups are needed to establish a cut-off value.

Effects of applying high-pass filtering in pelvimetry with Martius images.

The aim of this study is to investigate whether the results of pelvimetry using original radiographic Martius images and the same images with high-pass filtering applied ("edge images") would be consistent. A total of 30 primagravidas were included in this study. Three obstetricians independently measured the anteroposterior and transverse diameters of the pelvic inlet in the original and the edge images, recording the x- and y-coordinates of the four endpoints. A Wilcoxon signed rank sum test was performed on the coordinate data to evaluate differences between the original and edge images. In the analysis of all coordinate data, statistically significant differences were found in both x- and y-coordinates of the sacral promontory point (SPP). In the y-coordinate of the SPP, a statistically significant difference was found in 9 of 30 pairs of images, and in all 9 the anteroposterior diameter was shorter in the edge images compared to the original images due to the more caudal placement of the SPP. The coordinates of the SPP on original radiographs and their edge images were not consistent in pelvimetry using Martius images. Our results suggest that improved image contrast will allow obstetricians to better assess pelvic narrowing and cephalopelvic disproportion and even reduce radiographic dose, thereby reducing risks for pregnant women and their fetuses.

Numerical investigation on mixing behaviour in the contact zone of an industrial‐scale dissolved air flotation tank

AbstractThe mixing behaviour of the wastewater and the recycle bubbly water in the contact zone could affect the separation performance of dissolved air flotation systems. In this study, the mixing characteristics in the contact zone of an industrial‐scale dissolved air flotation tank were investigated using the computational fluid dynamics method. At first, the influence of the turbulence model on the simulation results was clarified. It is demonstrated that the realizable k‐ε model could predict the gas holdup distribution with better accuracy, and the maximum relative deviation between the predicted gas holdup and the experimental results is only 10%. The influence of the geometry and operating parameters on the mixing process was then studied numerically. It is found that the mixing performance in the contact zone could be improved by decreasing the height position of the nozzle inlet in a certain range. The reason is that microbubbles disperse better in the bottom region and a double circulation flow state forms in the contact zone when the nozzle inlet is installed at a low height. Additionally, the mixing process could be further enhanced by decreasing the diameter of the nozzle inlet. As to the operating conditions, increasing the recycle ratio could not only increase the gas holdup but also improve the mixing performance in the contact zone. When the recycle flow rate remains constant, increasing the wastewater flow rate will lead to a decrease in gas holdup and deterioration of the mixing effect.

X-ray Pelvimetry Has No Impact on the Outcomes of Trial of Labor after Cesarean Delivery: A Retrospective Single-center Study.

Few studies have examined the relationship between pelvic size and the success or failure of trial of labor after cesarean delivery (TOLAC). Here we aimed to determine whether pelvic size and morphological data obtained from radiography contribute to the first successful TOLAC. This retrospective single-center observational study enrolled pregnant women who underwent TOLAC between 2010 and 2021. The results of X-ray pelvimetry data, including obstetric conjugate (OC), transverse diameter of the pelvic inlet (TD), anteroposterior diameter of the pelvic inlet (APD), shape of the pelvic inlet, and other obstetrical clinical data, were compared between the success and failure groups. Seventy-five patients in successful group after excluding 35 patients with previous successful TOLAC, and 21 patients in failure group were eligible. The failure group had a higher rate of previous cesarean sections due to failed labor trials (p = 0.042) and heavier newborns (p = 0.014). OC, TD, and APD on X-ray pelvimetry did not differ significantly between the two groups nor did the shape of the pelvic inlet affect the success rate for TOLAC. The generalized linear model identified a history of failed trials of labor as a significant predictor of failed TOLAC (odds ratio, 0.26; 95% confidence interval 0.071-0.923; p = 0.037), whereas no pelvimetric parameters were found. Pelvic size and morphological findings have no discernible impact on the outcomes of TOLAC. The universal application of X-ray pelvimetry in all women attempting TOLAC may not have significant clinical relevance.

Enhancing the efficiency of two‐stage cyclones without increasing pressure drop by optimizing inlet and outlet dimensions

AbstractEfforts to enhance cyclone separators aim to minimize gas energy consumption while improving separation efficiency. This study attempts to achieve this goal for cyclones arranged in series using straightforward methods. Experimental and numerical simulation analyses were performed to study the effect of matching inlet and outlet diameters on the performance of a two‐stage tandem cyclone separator. The results show that the matching method, in which the inlet gas velocities of both stages are higher than the outlet gas velocity, has a better separation efficiency. The efficiency and pressure drop models of the two‐stage cyclones in series were constructed using the response surface methodology (RSM) to obtain the optimal combination of inlet size and exhaust pipe diameter. Experimental tests showed that the accuracy of this model was reasonable. At different permitted pressure drops, the optimized structure revealed that: (1) The inlet area should be smaller than the outlet area for each cyclone stage. (2) The secondary inlet size (KA) should be as large as possible. (3) dr decreases while KA increases in each step.

Numerical Simulation and Thermal Analysis of Pressurized Hydrogen Vehicle Cylinders: Impact of Geometry and Phase Change Materials

This comprehensive study investigates the nuanced aspects of pressurized hydrogen vehicle cylinders during refueling, employing numerical simulation and thermal analysis. The examination encompasses the intricate dynamics influenced by cylinder geometry, mass flow rate variations, and the integration of phase change materials (PCMs). Simulations involving cylinders with diverse length-to-diameter ratios and inlet diameters highlight the impact of these parameters on temperature control. Notably, smaller length-to-diameter ratios prove effective for temperature regulation, while larger inlet diameters mitigate temperature rise. The study further explores the role of varying mass flow rates, revealing that an increasing flow rate during refueling results in the lowest temperature rise. In addition to geometry and mass flow rate considerations, the integration of PCMs is a focal point. Modeling and parametric analysis are employed to assess the feasibility of incorporating these materials. The study contributes valuable insights into optimizing the thermal performance and safety of hydrogen fuel systems. The holistic approach considers the interplay of geometry, mass flow rate dynamics, and the innovative use of PCMs, offering a multifaceted understanding of the factors influencing pressurized hydrogen vehicle cylinders.