Pub Date : 2024-06-02DOI: 10.37934/cfdl.16.10.6480
Harinaldi Harinaldi, Farhan T Pratama
The rapid evolution of global transportation technology is exemplified by Indonesia's innovative high-speed train initiative, linking Jakarta and Bandung in an impressive 45 minutes. Operating at 350 km/h, the HST CR400AF underscores the importance of aerodynamics in high-speed rail systems. This study delves into the significant impact of crosswind on key aerodynamic factors (drag, lift, rolling moment) within the tunnel-bridge-tunnel configuration. Leveraging Computational Fluid Dynamics (CFD) through ANSYS FLUENT, the analysis explores crosswind variations at 0 m/s, 10 m/s, and 25 m/s. Results reveal a proportional increase in aerodynamic load with higher crosswind intensities: 1.67 times for drag, 58.8 times for lift, and 29.8 times for rolling moment. Notable observations include pronounced aerodynamic load fluctuations during the "OUT" process, with the head section bearing the greatest load, followed by the tail and middle sections. These findings contribute valuable insights to the global discourse on enhancing safety and efficiency in high-speed rail systems
{"title":"Transient Analysis on the Crosswind Effect to the Aerodynamics of High-speed Train Travelled on the Bridge Between Two Tunnels at Jakarta -Bandung Track","authors":"Harinaldi Harinaldi, Farhan T Pratama","doi":"10.37934/cfdl.16.10.6480","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.6480","url":null,"abstract":"The rapid evolution of global transportation technology is exemplified by Indonesia's innovative high-speed train initiative, linking Jakarta and Bandung in an impressive 45 minutes. Operating at 350 km/h, the HST CR400AF underscores the importance of aerodynamics in high-speed rail systems. This study delves into the significant impact of crosswind on key aerodynamic factors (drag, lift, rolling moment) within the tunnel-bridge-tunnel configuration. Leveraging Computational Fluid Dynamics (CFD) through ANSYS FLUENT, the analysis explores crosswind variations at 0 m/s, 10 m/s, and 25 m/s. Results reveal a proportional increase in aerodynamic load with higher crosswind intensities: 1.67 times for drag, 58.8 times for lift, and 29.8 times for rolling moment. Notable observations include pronounced aerodynamic load fluctuations during the \"OUT\" process, with the head section bearing the greatest load, followed by the tail and middle sections. These findings contribute valuable insights to the global discourse on enhancing safety and efficiency in high-speed rail systems","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"2 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-02DOI: 10.37934/cfdl.16.10.112125
Rhafiq Abdul Ghani, Muthia Elma, Aulia Rahma, Zahratun Nisa
Nowadays, polymer as the raw material has been utilized in the development of Hollow Fibre (HF) membranes. PVDF is a commonly used for HF membrane material. However, it has hydrophobicity properties and lead membrane becomes low permeability and fouling. Therefore, to avoid these membranes problems, the incorporation of inorganic nanoparticles into PVDF membranes matrix is necessary to be applied for significantly improving PVDF membranes performance. This study investigates the characteristics and performance of PVDF-TiO2 HF membranes using spent bleaching earth (SBE) as a promising material from industrial waste as a renewable inorganic nanoparticle. This novel PVDF-TiO2-SBE HF membrane was fabricated using the subsequent steps: The preparation process incorporates SBE revival through solvent extraction and thermal treatment alongside the wet spinning technique for membrane fabrication. The Fourier transform infrared (FTIR) functional groups, scanning electron microscope (SEM) morphology, water contact angle and pure water flux performance were investigated to specifically understand the performance of this typical HF membranes. The IR results show that Si-O-Si groups were found in the membrane matrices due to the addition of SBE material. The addition of TiO2-SBE particles also indicate a sandwich (sponge-finger-like) morphological structure on the cross-sectional, a rough and porous surface structures. The hydrophilic properties of the HF membrane and pure water flux performance are determined by the composition of the TiO2-SBE mixture added as an additive material. The minimum contact angle found at 74.33°, while the water flux is 5.81 kg.m-2.h-1 on the identical HF membrane. Accordingly, this approach significantly enhances the properties of the pure PVDF HF membrane.
{"title":"A A Novel Poly (vinylidene) Fluoride/TiO2/Spent Bleaching Earth for Enhancing Hydrophilic Hollow Fibre Membrane","authors":"Rhafiq Abdul Ghani, Muthia Elma, Aulia Rahma, Zahratun Nisa","doi":"10.37934/cfdl.16.10.112125","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.112125","url":null,"abstract":"Nowadays, polymer as the raw material has been utilized in the development of Hollow Fibre (HF) membranes. PVDF is a commonly used for HF membrane material. However, it has hydrophobicity properties and lead membrane becomes low permeability and fouling. Therefore, to avoid these membranes problems, the incorporation of inorganic nanoparticles into PVDF membranes matrix is necessary to be applied for significantly improving PVDF membranes performance. This study investigates the characteristics and performance of PVDF-TiO2 HF membranes using spent bleaching earth (SBE) as a promising material from industrial waste as a renewable inorganic nanoparticle. This novel PVDF-TiO2-SBE HF membrane was fabricated using the subsequent steps: The preparation process incorporates SBE revival through solvent extraction and thermal treatment alongside the wet spinning technique for membrane fabrication. The Fourier transform infrared (FTIR) functional groups, scanning electron microscope (SEM) morphology, water contact angle and pure water flux performance were investigated to specifically understand the performance of this typical HF membranes. The IR results show that Si-O-Si groups were found in the membrane matrices due to the addition of SBE material. The addition of TiO2-SBE particles also indicate a sandwich (sponge-finger-like) morphological structure on the cross-sectional, a rough and porous surface structures. The hydrophilic properties of the HF membrane and pure water flux performance are determined by the composition of the TiO2-SBE mixture added as an additive material. The minimum contact angle found at 74.33°, while the water flux is 5.81 kg.m-2.h-1 on the identical HF membrane. Accordingly, this approach significantly enhances the properties of the pure PVDF HF membrane.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"26 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-02DOI: 10.37934/cfdl.16.10.8193
Dan Mugisidi, Oktarina Heriyani
Water is a primary need for living creatures, and water scarcity can trigger a crisis. Water scarcity is becoming an issue in Indonesia, especially in coastal village areas, including salt-producing areas. Salt production involves evaporating large amounts of seawater in concentration ponds. Using evaporated seawater as a source of clean water would reduce the risk of water scarcity. Therefore, this study aims to obtain fresh water by condensing water vapour that evaporates in a desalination unit. More specifically, the study uses a vortex generator to increase the rate and efficiency of evaporation in a forced-flow desalination unit. This research was conducted indoors to reduce uncontrollable variables. An evaporation container with a volume of 0.35 m3 was filled with seawater. The rate of evaporation in the desalination unit with a vortex generator was compared to that in a unit without a vortex generator. The results show that the vortex generator leads to faster evaporation. The rate of evaporation with a vortex generator was 13% higher than that without a vortex generator, and the gained output ratio increased 14% with the vortex generator. Therefore, it can be concluded that vortex generators can improve the performance of desalination equipment
{"title":"Improving the Performance of a Forced-flow Desalination Unit using a Vortex Generator","authors":"Dan Mugisidi, Oktarina Heriyani","doi":"10.37934/cfdl.16.10.8193","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.8193","url":null,"abstract":"Water is a primary need for living creatures, and water scarcity can trigger a crisis. Water scarcity is becoming an issue in Indonesia, especially in coastal village areas, including salt-producing areas. Salt production involves evaporating large amounts of seawater in concentration ponds. Using evaporated seawater as a source of clean water would reduce the risk of water scarcity. Therefore, this study aims to obtain fresh water by condensing water vapour that evaporates in a desalination unit. More specifically, the study uses a vortex generator to increase the rate and efficiency of evaporation in a forced-flow desalination unit. This research was conducted indoors to reduce uncontrollable variables. An evaporation container with a volume of 0.35 m3 was filled with seawater. The rate of evaporation in the desalination unit with a vortex generator was compared to that in a unit without a vortex generator. The results show that the vortex generator leads to faster evaporation. The rate of evaporation with a vortex generator was 13% higher than that without a vortex generator, and the gained output ratio increased 14% with the vortex generator. Therefore, it can be concluded that vortex generators can improve the performance of desalination equipment","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"23 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-02DOI: 10.37934/cfdl.16.10.140153
Afrah Turki Awad, Abdulelah Hameed Yaseen, Adnan M. Hussein
In a variety of engineering applications, the efficacy of heat dissipation in mobile cooling systems is greatly influenced by the Backward Facing Step. Its significance in optimizing cooling solutions for mobile devices is highlighted by the fact that its design and fluid dynamics are crucial in minimizing skin friction and improving passive heat transfer. In this paper, we present a verification of an advanced numerical model for heat transfer and fluid flow through a Backward Facing Step, used in mobile cooling. The objective of this study is to explore fluid separation, a method enhancing passive heat transfer and reducing skin friction. ANSYS/FLUENT software has been used to solve the backward facing step in a horizontal duct filled with pure water. Carbon nanotube (CNT) dispresed into the base fluid at different volume fractions of 0.2%, 0.65%, and 1%. This study focused on laminar flow conditions ranging from Reynolds numbers 200 to 900. In order to reduce the computation time and ensuring the accuracy and reliability of numerical simulations, a grid independence study has been conducted. The findings revealed a substantial rise in the average Nusselt number and heat transfer coefficient with increased Reynolds number and volume fraction of nanoparticles. Specifically, the nanofluid (CNT/water) exhibited the highest average Nusselt number and heat transfer coefficient with volume fractions 1%. Furthermore, the research showed a decrease in the skin friction factor as both Reynolds number increased and nanoparticles’ volume fraction decreased. The increments of nanoparticles' concentrations lead to increase viscosity, promotes agglomeration, alters flow behaviour by inducing turbulence, and enhances heat transfer. These factors collectively contribute to higher skin friction due to increased resistance to fluid flow and disrupted streamline patterns
{"title":"Evaluation of Heat Transfer and Fluid Dynamics across a Backward Facing Step for Mobile Cooling Applications Utilizing CNT Nanofluid in Laminar Conditions","authors":"Afrah Turki Awad, Abdulelah Hameed Yaseen, Adnan M. Hussein","doi":"10.37934/cfdl.16.10.140153","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.140153","url":null,"abstract":"In a variety of engineering applications, the efficacy of heat dissipation in mobile cooling systems is greatly influenced by the Backward Facing Step. Its significance in optimizing cooling solutions for mobile devices is highlighted by the fact that its design and fluid dynamics are crucial in minimizing skin friction and improving passive heat transfer. In this paper, we present a verification of an advanced numerical model for heat transfer and fluid flow through a Backward Facing Step, used in mobile cooling. The objective of this study is to explore fluid separation, a method enhancing passive heat transfer and reducing skin friction. ANSYS/FLUENT software has been used to solve the backward facing step in a horizontal duct filled with pure water. Carbon nanotube (CNT) dispresed into the base fluid at different volume fractions of 0.2%, 0.65%, and 1%. This study focused on laminar flow conditions ranging from Reynolds numbers 200 to 900. In order to reduce the computation time and ensuring the accuracy and reliability of numerical simulations, a grid independence study has been conducted. The findings revealed a substantial rise in the average Nusselt number and heat transfer coefficient with increased Reynolds number and volume fraction of nanoparticles. Specifically, the nanofluid (CNT/water) exhibited the highest average Nusselt number and heat transfer coefficient with volume fractions 1%. Furthermore, the research showed a decrease in the skin friction factor as both Reynolds number increased and nanoparticles’ volume fraction decreased. The increments of nanoparticles' concentrations lead to increase viscosity, promotes agglomeration, alters flow behaviour by inducing turbulence, and enhances heat transfer. These factors collectively contribute to higher skin friction due to increased resistance to fluid flow and disrupted streamline patterns","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"10 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-02DOI: 10.37934/cfdl.16.10.126139
Hien Le Tat, Nguyen Duy Anh, Nguyen Thi Ngoc Hoa
Up to now, there is no developed ‘universal’ turbulence model in CFD simulation, so employing an appropriate turbulence model is crucial for accurately predicting the hydrodynamics of a ship, especially for submarines. This study focuses on investigating the impact of turbulence models on the predicted results in frictional and pressure resistance components and flow features around the submarine at different ship velocities by the CFD method. Four various turbulence models consisting of the Reynolds Stress Model, realizable k-ε two-layer, standard k-ω, and SST k-ω turbulence models are investigated in this study. The obtained numerical results demonstrate variations in resistance and the flow patterns around the submarine due to the effect of turbulence model. Based on the obtained results, the paper points out that, the choice of turbulence model significantly affects the frictional resistance of the submarine and the SST K-ω turbulence model provided the highest level of accuracy in comparison with experimental data. The model employed in this research is the DARPA SUBOFF submarine model
{"title":"Numerical Investigate the Effect of Turbulence Models on the CFD Computation of Submarine Resistance","authors":"Hien Le Tat, Nguyen Duy Anh, Nguyen Thi Ngoc Hoa","doi":"10.37934/cfdl.16.10.126139","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.126139","url":null,"abstract":"Up to now, there is no developed ‘universal’ turbulence model in CFD simulation, so employing an appropriate turbulence model is crucial for accurately predicting the hydrodynamics of a ship, especially for submarines. This study focuses on investigating the impact of turbulence models on the predicted results in frictional and pressure resistance components and flow features around the submarine at different ship velocities by the CFD method. Four various turbulence models consisting of the Reynolds Stress Model, realizable k-ε two-layer, standard k-ω, and SST k-ω turbulence models are investigated in this study. The obtained numerical results demonstrate variations in resistance and the flow patterns around the submarine due to the effect of turbulence model. Based on the obtained results, the paper points out that, the choice of turbulence model significantly affects the frictional resistance of the submarine and the SST K-ω turbulence model provided the highest level of accuracy in comparison with experimental data. The model employed in this research is the DARPA SUBOFF submarine model","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"2 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The fuel cells performance is significantly impacted by both design and operational factors. The effective distribution of reactants within the flow fields is facilitated by the design of the flow channels. Therefore, the geometry of the flow channels and the overall design of the flow field play a crucial role in determining the fuel cells performance. Among various flow field designs, the serpentine flow field demonstrates superior performance compared to others. In this research, a three-dimensional proton exchange membrane fuel cell model was developed and used to study the influence of three-pass serpentine flow field on cell performance across varying operating voltages (0.9 V, 0.7 V and 0.5 V). The purpose of this research is to simulate and evaluate the comportment of the three-pass serpentine flow channels configuration by analyzing several parameters such as channels velocity distribution, oxygen mole fraction, pressure distribution and electrolyte current density along the z-axis at the cathode under different operating voltages. Numerical simulations were conducted using the COMSOL Multiphysics software. Therefore, this software is used to solve numerically the complete three-dimensional model with the governing equations of charge conservation, species transport, momentum, and continuity. The obtained results indicate that among different operating voltages, the cell voltage of 0.5 V demonstrated the highest channels velocity distribution, pressure distribution, and electrolyte current density. Moreover, it is found that at an operating voltage of 0.5 V, there is an important decrease in oxygen concentrations indicating a significant oxygen consumption in the fuel cell which improves the overall efficiency. This work contributes valuable insights to the optimization of fuel cell performance, specifically highlighting the favorable outcomes associated with the three-pass serpentine flow field design at lower operating voltages
燃料电池的性能受到设计和运行因素的极大影响。流道的设计有助于反应物在流场内的有效分布。因此，流道的几何形状和流场的整体设计在决定燃料电池性能方面起着至关重要的作用。在各种流场设计中，蛇形流场的性能优于其他流场。本研究开发了一个三维质子交换膜燃料电池模型，用于研究三通蛇形流场在不同工作电压（0.9 伏、0.7 伏和 0.5 伏）下对电池性能的影响。本研究的目的是通过分析不同工作电压下阴极沿 Z 轴的通道速度分布、氧分子分数、压力分布和电解质电流密度等参数，模拟和评估三通蛇形流道配置的协调性。数值模拟使用 COMSOL Multiphysics 软件进行。因此，该软件用于数值求解具有电荷守恒、物种传输、动量和连续性等控制方程的完整三维模型。结果表明，在不同的工作电压下，电池电压为 0.5 V 时的通道速度分布、压力分布和电解质电流密度最高。此外，研究还发现，在 0.5 V 的工作电压下，氧气浓度显著下降，这表明燃料电池中的氧气消耗量很大，从而提高了整体效率。这项研究为优化燃料电池性能提供了宝贵的见解，特别是强调了在较低工作电压下三段式蛇形流场设计的有利结果。
{"title":"Performance Investigation of PEM Fuel Cell with Three-Pass Serpentine Flow Fields under Varying Operating Voltages","authors":"Kaoutar Kabouchi, Mohamed Karim Ettouhami, Hamid Mounir, Khalid Elbikri","doi":"10.37934/cfdl.16.10.5463","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.5463","url":null,"abstract":"The fuel cells performance is significantly impacted by both design and operational factors. The effective distribution of reactants within the flow fields is facilitated by the design of the flow channels. Therefore, the geometry of the flow channels and the overall design of the flow field play a crucial role in determining the fuel cells performance. Among various flow field designs, the serpentine flow field demonstrates superior performance compared to others. In this research, a three-dimensional proton exchange membrane fuel cell model was developed and used to study the influence of three-pass serpentine flow field on cell performance across varying operating voltages (0.9 V, 0.7 V and 0.5 V). The purpose of this research is to simulate and evaluate the comportment of the three-pass serpentine flow channels configuration by analyzing several parameters such as channels velocity distribution, oxygen mole fraction, pressure distribution and electrolyte current density along the z-axis at the cathode under different operating voltages. Numerical simulations were conducted using the COMSOL Multiphysics software. Therefore, this software is used to solve numerically the complete three-dimensional model with the governing equations of charge conservation, species transport, momentum, and continuity. The obtained results indicate that among different operating voltages, the cell voltage of 0.5 V demonstrated the highest channels velocity distribution, pressure distribution, and electrolyte current density. Moreover, it is found that at an operating voltage of 0.5 V, there is an important decrease in oxygen concentrations indicating a significant oxygen consumption in the fuel cell which improves the overall efficiency. This work contributes valuable insights to the optimization of fuel cell performance, specifically highlighting the favorable outcomes associated with the three-pass serpentine flow field design at lower operating voltages","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"45 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141274104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Savonius turbine is a vertical-axis wind turbine (VAWT), which has the advantage of being able to capture wind from different directions. This turbine is suitable for high turbulent wind areas. The blade on the Savonius turbine used in this study is equipped with a Magnus rotor with dimensions of 120 mm in diameter and 720 mm in height. The main purpose of this study is to determine the torque and pressure generated by turbines with three and four blades. The design was then tested numerically with variations in wind velocity. The simulation model was created using computer-aided design software, namely Autodesk Inventor 2023, and then inputted into computational fluid dynamics (CFD) software, namely Ansys Workbench 2022 R2. Wind velocities were varied by 3, 5, 7, 9, and 11 m/s and simulated using transient time with constant wind velocity. The result of this study is that the largest pressure is generated by a hybrid turbine with four blades at a wind velocity of 11 m/s. The results show that the torque and wind pressure that occurs in three- and four-blade hybrid turbines tend to rise; the faster the wind, the higher the torque and pressure of both hybrid turbines
{"title":"Savonius-Magnus Hybrid Turbine Design Performance Based on Computational Fluid Dynamics","authors":"Rr. Heni Hendaryati, Achmad Fauzan Hery Soegiharto, Dolly Salwansyah, Andinusa Rahmandika, Bahrul Jalaali","doi":"10.37934/cfdl.16.10.4353","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.4353","url":null,"abstract":"Savonius turbine is a vertical-axis wind turbine (VAWT), which has the advantage of being able to capture wind from different directions. This turbine is suitable for high turbulent wind areas. The blade on the Savonius turbine used in this study is equipped with a Magnus rotor with dimensions of 120 mm in diameter and 720 mm in height. The main purpose of this study is to determine the torque and pressure generated by turbines with three and four blades. The design was then tested numerically with variations in wind velocity. The simulation model was created using computer-aided design software, namely Autodesk Inventor 2023, and then inputted into computational fluid dynamics (CFD) software, namely Ansys Workbench 2022 R2. Wind velocities were varied by 3, 5, 7, 9, and 11 m/s and simulated using transient time with constant wind velocity. The result of this study is that the largest pressure is generated by a hybrid turbine with four blades at a wind velocity of 11 m/s. The results show that the torque and wind pressure that occurs in three- and four-blade hybrid turbines tend to rise; the faster the wind, the higher the torque and pressure of both hybrid turbines","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"18 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper reports on the numerical turbulence model in predicting mass, momentum and heat transfer in a partially divided cavity heated from the side using buoyancy-extended eddy-viscosity and elliptic relaxation approach with the algebraic expressions for the Reynold stress tensor and turbulent heat flux vector. The CDS (central differencing scheme) and LUDS (linear upwind differencing scheme) were used as the discretization method and the governing equations were solved using the finite volume method and Navier-Stokes solver. Validation of the model has been carried out by experimental data of convective flow in the cavity as well as by numerical data DNS (direct numerical simulation). The model agrees very well with the experiment and DNS and it is also able to demonstrate the performance which is comparable to that of the previous advanced second-moment closure model (SMC) in the literature. The results show that the model is suitable for use in simulations of the turbulent convective flow in a cavity with partition and it has the potential to be applied to more complex cavities and a wide range of turbulence levels.
本文报告了利用浮力-扩展涡粘法和椭圆松弛法以及雷诺应力张量和湍流热通量矢量的代数表达式，预测从侧面加热的部分分割空腔中的质量、动量和热量传递的数值湍流模型。采用 CDS（中央差分方案）和 LUDS（线性上风差分方案）作为离散化方法，并使用有限体积法和纳维-斯托克斯求解器求解支配方程。模型通过空腔对流实验数据和 DNS（直接数值模拟）数值数据进行了验证。该模型与实验和 DNS 非常吻合，其性能也可与先前文献中的先进秒矩闭合模型（SMC）相媲美。结果表明，该模型适用于模拟带隔板空腔中的湍流对流，并有潜力应用于更复杂的空腔和更广泛的湍流水平。
{"title":"Application of Extended Eddy-viscosity and Elliptic-Relaxation Approaches to Turbulent Convective Flow in a Partially Divided Cavity","authors":"Gunarjo Suryanto Budi, Sasa Kenjeres","doi":"10.37934/cfdl.16.10.111","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.111","url":null,"abstract":"The paper reports on the numerical turbulence model in predicting mass, momentum and heat transfer in a partially divided cavity heated from the side using buoyancy-extended eddy-viscosity and elliptic relaxation approach with the algebraic expressions for the Reynold stress tensor and turbulent heat flux vector. The CDS (central differencing scheme) and LUDS (linear upwind differencing scheme) were used as the discretization method and the governing equations were solved using the finite volume method and Navier-Stokes solver. Validation of the model has been carried out by experimental data of convective flow in the cavity as well as by numerical data DNS (direct numerical simulation). The model agrees very well with the experiment and DNS and it is also able to demonstrate the performance which is comparable to that of the previous advanced second-moment closure model (SMC) in the literature. The results show that the model is suitable for use in simulations of the turbulent convective flow in a cavity with partition and it has the potential to be applied to more complex cavities and a wide range of turbulence levels.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"7 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-02DOI: 10.37934/cfdl.16.10.1242
Berlian Arswendo Adietya, Husein Syahab, Mochammad Nasir, Wasis Dwi Aryawan, I Ketut Aria Pria Utama
Numerical analysis was conducted to assess the impact of fins on the B4-70 and Ka4-70 propeller performance. The study explored different fin variations, specifically bare fins, Propeller Boss Cap Fins (PBCF), and propeller nozzles, using computational fluid dynamics (CFD) simulations. To obtain the best results, the researchers utilized the explicit algebraic stress model (EASM) based on Reynolds-Averaged Navier-Stokes (RANS) equations and turbulence modelling. The primary goal of this study was to improve the energy efficiency of ships by examining various propeller configurations, both open and ducted. The overall conclusions indicated that the B4-70 PBCF convergent and Ka4-70 PBCF divergent with the addition of nozzle 19A exhibited the highest efficiency based on the EASM analysis. The CFD simulation results for both B4-70 and Ka4-70 propellers, utilizing a nozzle 19A with added boss cap fins, revealed several noteworthy phenomena. Firstly, for the B4-70 propeller, efficiency (η0) at J = 0.6 to J = 0.8 showed an increase of 1% to 2%. Secondly, concerning the Ka4-70 propeller, efficiency (η0) at J = 0.6 to J = 0.8 increased by 2% to 10%. These findings clearly demonstrate that the use of an ESD, such as the nozzle 19A with added boss cap fins, enhances the propulsion performance of the ship. It is evident that the CFD approach remains suitable and reliable for overall simulations.
{"title":"Numerical Analysis into the Improvement Performance of Ducted Propeller by using Fins: Case Studies on Types B4-70 and Ka4-70","authors":"Berlian Arswendo Adietya, Husein Syahab, Mochammad Nasir, Wasis Dwi Aryawan, I Ketut Aria Pria Utama","doi":"10.37934/cfdl.16.10.1242","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.1242","url":null,"abstract":"Numerical analysis was conducted to assess the impact of fins on the B4-70 and Ka4-70 propeller performance. The study explored different fin variations, specifically bare fins, Propeller Boss Cap Fins (PBCF), and propeller nozzles, using computational fluid dynamics (CFD) simulations. To obtain the best results, the researchers utilized the explicit algebraic stress model (EASM) based on Reynolds-Averaged Navier-Stokes (RANS) equations and turbulence modelling. The primary goal of this study was to improve the energy efficiency of ships by examining various propeller configurations, both open and ducted. The overall conclusions indicated that the B4-70 PBCF convergent and Ka4-70 PBCF divergent with the addition of nozzle 19A exhibited the highest efficiency based on the EASM analysis. The CFD simulation results for both B4-70 and Ka4-70 propellers, utilizing a nozzle 19A with added boss cap fins, revealed several noteworthy phenomena. Firstly, for the B4-70 propeller, efficiency (η0) at J = 0.6 to J = 0.8 showed an increase of 1% to 2%. Secondly, concerning the Ka4-70 propeller, efficiency (η0) at J = 0.6 to J = 0.8 increased by 2% to 10%. These findings clearly demonstrate that the use of an ESD, such as the nozzle 19A with added boss cap fins, enhances the propulsion performance of the ship. It is evident that the CFD approach remains suitable and reliable for overall simulations.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"50 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141274007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Divya D Shetty, Mohammad Zuber, Chethan K N, Laxmikant G, Irfan Anjum Badruddin Magami, Chandrakant R Kini
Lithium-ion batteries are frequently utilized in electric vehicles because of their high energy density and prolonged cycle life. Maintaining the right temperature range is crucial since lithium-ion batteries' performance and lifespan are highly sensitive to temperature. This study discusses a practical battery heat control system in this setting. The phenomenon of heat generation and significant thermal problems with lithium-ion batteries are reviewed in this work. The studies on various battery thermal management systems (BTMS) are then thoroughly analysed and arranged into groups based on thermal cycle possibilities. Direct refrigerant two-phase cooling, second-loop liquid cooling, and cabin air cooling are all components of the BTMS. Phase change material cooling, heat pipe cooling, and thermoelectric element cooling are all future parts of the BTMS. The maximum temperature and maximum temperature differential of the batteries are examined for each BTMS, and a suitable BTMS that addresses the drawbacks of each system is discussed. Finally, a novel BTMS is suggested as a practical thermal management solution for lithium-ion batteries with high energy density.
{"title":"Advancements in Battery Thermal Management for High-Energy-Density Lithium-Ion Batteries in Electric Vehicles: A Comprehensive Review","authors":"Divya D Shetty, Mohammad Zuber, Chethan K N, Laxmikant G, Irfan Anjum Badruddin Magami, Chandrakant R Kini","doi":"10.37934/cfdl.16.9.1438","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.1438","url":null,"abstract":"Lithium-ion batteries are frequently utilized in electric vehicles because of their high energy density and prolonged cycle life. Maintaining the right temperature range is crucial since lithium-ion batteries' performance and lifespan are highly sensitive to temperature. This study discusses a practical battery heat control system in this setting. The phenomenon of heat generation and significant thermal problems with lithium-ion batteries are reviewed in this work. The studies on various battery thermal management systems (BTMS) are then thoroughly analysed and arranged into groups based on thermal cycle possibilities. Direct refrigerant two-phase cooling, second-loop liquid cooling, and cabin air cooling are all components of the BTMS. Phase change material cooling, heat pipe cooling, and thermoelectric element cooling are all future parts of the BTMS. The maximum temperature and maximum temperature differential of the batteries are examined for each BTMS, and a suitable BTMS that addresses the drawbacks of each system is discussed. Finally, a novel BTMS is suggested as a practical thermal management solution for lithium-ion batteries with high energy density.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"40 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141008344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：