Pub Date : 2024-05-06DOI: 10.37934/cfdl.16.9.126142
Gopinathan Sumathi, Mini, Prathi Vijaya, Kumar, Shaik Mohammed
The design and optimization of systems such as nuclear reactors, solar collectors, and thermal power plants may benefit from an understanding of the behaviour of nanofluids with chemical processes, thermal radiation, and magnetic fields over inclined surfaces with heat sources.This review looks at the magnetohydrodynamic (MHD) flow of a Williamson nanofluid over an inclinable stretched sheet and the impact of thermal radiation, heat source, and chemical processes. The outcomes of the generation of heat or absorption, as well as thermal radiation, are all factored into account in the energy equation. On the other hand, the mass transport equation also takes into account chemical interactions.The similarity substitution serves to turn the governed partial differential equations for velocity, temperature, and concentration into ordinary differential equations, which are then numerically resolved with Mathematica's NDSolve program. Changes in temperature, concentration, and dimensionless velocity as a function of various factors are graphically touched upon. The temperature diminishes while the Prandtl number accelerates as the thermal boundary layer thins and the viscosity enrichment. The temperature contour develops along with the magnetic field strength. When all the parameters were compared for a particular case, a very good association was discovered. Depending on the precise conclusions and understandings drawn from the investigation of chemically radiative MHD nanofluid flow over inclined surfaces with a heat source, the applications may range greatly. It's important to remember that such research often aids in the creation of more effective and environmentally friendly solutions in a variety of sectors.
{"title":"Numerical Analysis Study of Chemically Radiative MHD Williamson Nanofluid Flow over an Inclined Surface with Heat Source","authors":"Gopinathan Sumathi, Mini, Prathi Vijaya, Kumar, Shaik Mohammed","doi":"10.37934/cfdl.16.9.126142","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.126142","url":null,"abstract":"The design and optimization of systems such as nuclear reactors, solar collectors, and thermal power plants may benefit from an understanding of the behaviour of nanofluids with chemical processes, thermal radiation, and magnetic fields over inclined surfaces with heat sources.This review looks at the magnetohydrodynamic (MHD) flow of a Williamson nanofluid over an inclinable stretched sheet and the impact of thermal radiation, heat source, and chemical processes. The outcomes of the generation of heat or absorption, as well as thermal radiation, are all factored into account in the energy equation. On the other hand, the mass transport equation also takes into account chemical interactions.The similarity substitution serves to turn the governed partial differential equations for velocity, temperature, and concentration into ordinary differential equations, which are then numerically resolved with Mathematica's NDSolve program. Changes in temperature, concentration, and dimensionless velocity as a function of various factors are graphically touched upon. The temperature diminishes while the Prandtl number accelerates as the thermal boundary layer thins and the viscosity enrichment. The temperature contour develops along with the magnetic field strength. When all the parameters were compared for a particular case, a very good association was discovered. Depending on the precise conclusions and understandings drawn from the investigation of chemically radiative MHD nanofluid flow over inclined surfaces with a heat source, the applications may range greatly. It's important to remember that such research often aids in the creation of more effective and environmentally friendly solutions in a variety of sectors.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"83 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141010922","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}
I. D. Made, Cipta Santosa, Gede Nyoman, Suta Waisnawa, P. Sunu, Wayan Temaja, Liang Li
This study is aimed to develop a simulation to improve the performance of the finned tube evaporator which is applied to the refrigerated display cabinet. CFD model was developed to be able to analyse the characteristics of air flow inside the fin gap and air side heat transfer coefficient. Geometry of the model of overall finned tube evaporator is considered covering two aluminium wavy fins with an air flow in between, combination of staggered cooper tubes with refrigerant flow inside. Fin gap is designed 4 mm to anticipate frost on the fin surface that can block air flow. Turbulence models used in the study is the realizable k-ε turbulence which had the best performance turbulence model and it was validated with secondary data from previous studies and shows the lowest error only 5.9 %. The use of CFD was found to be sufficiently representative of the heat transfer characteristics of evaporators, and acted as an effective simulation tool to determine the heat transfer coefficient in order to improve efficiency in terms of improved design. The characteristics of air flow between the fin gap and around the tube was obtained various and complex. In the case study the entry velocity of 1.7 m /s at the highest turbulence condition of the first row can reach speeds of 2.75 m/s. Hight turbulence regime in flow can indicate higher the heat transfer coefficient of the evaporator.
{"title":"CFD Air Flow Evaluation of Finned Tube Evaporator for Refrigerated Display Cabinet Application","authors":"I. D. Made, Cipta Santosa, Gede Nyoman, Suta Waisnawa, P. Sunu, Wayan Temaja, Liang Li","doi":"10.37934/cfdl.16.9.5263","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.5263","url":null,"abstract":"This study is aimed to develop a simulation to improve the performance of the finned tube evaporator which is applied to the refrigerated display cabinet. CFD model was developed to be able to analyse the characteristics of air flow inside the fin gap and air side heat transfer coefficient. Geometry of the model of overall finned tube evaporator is considered covering two aluminium wavy fins with an air flow in between, combination of staggered cooper tubes with refrigerant flow inside. Fin gap is designed 4 mm to anticipate frost on the fin surface that can block air flow. Turbulence models used in the study is the realizable k-ε turbulence which had the best performance turbulence model and it was validated with secondary data from previous studies and shows the lowest error only 5.9 %. The use of CFD was found to be sufficiently representative of the heat transfer characteristics of evaporators, and acted as an effective simulation tool to determine the heat transfer coefficient in order to improve efficiency in terms of improved design. The characteristics of air flow between the fin gap and around the tube was obtained various and complex. In the case study the entry velocity of 1.7 m /s at the highest turbulence condition of the first row can reach speeds of 2.75 m/s. Hight turbulence regime in flow can indicate higher the heat transfer coefficient of the evaporator.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"1 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141010849","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}
In this present article, we analyzed the effects of Thermal diffusion and chemical reaction on nonlinear mixed convection MHD flow of viscous, incompressible and electrically conducting fluid past an inclined porous channel under the influence of thermal radiation and chemical reaction. The transformed conservation equations are solved analytically subject to physically appropriate boundary conditions by using two term perturbation technique. The numerical values of fluid velocity, fluid temperature and species concentration are displayed graphically whereas those of skin friction coefficient, rate of heat transfer and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. It is observed that the velocity is decreased with increasing magnetic field parameter. The resultant velocity and concentration has enhances with increasing thermal diffusion parameters. The study is relevant to chemical materials processing applications.
{"title":"Consequences of Thermal Diffusion and Chemical Reaction on Mixed Convection MHD Casson Fluid through Porous Media with Inclined Plates","authors":"Sunita Rani Yedhiri, Srinivasa Rao Puchakayala, Kalyan Kumar Palaparthi, Haribabu Kommaddi","doi":"10.37934/cfdl.16.9.6480","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.6480","url":null,"abstract":"In this present article, we analyzed the effects of Thermal diffusion and chemical reaction on nonlinear mixed convection MHD flow of viscous, incompressible and electrically conducting fluid past an inclined porous channel under the influence of thermal radiation and chemical reaction. The transformed conservation equations are solved analytically subject to physically appropriate boundary conditions by using two term perturbation technique. The numerical values of fluid velocity, fluid temperature and species concentration are displayed graphically whereas those of skin friction coefficient, rate of heat transfer and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. It is observed that the velocity is decreased with increasing magnetic field parameter. The resultant velocity and concentration has enhances with increasing thermal diffusion parameters. The study is relevant to chemical materials processing applications.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"3 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141006471","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}
Siti Suzilliana Putri Mohamed Isa, Hazirah Mohd Azmi, Nanthini Balakrishnan, Aina Suhaiza Mohamad Nazir, Kartini Ahmad, Nurul Syuhada Ismail, Norihan Md. Arifin, Haliza Rosali
The three-dimensional (3D) model of the fluid flow model with length, breadth, and height or depth is the advanced and precise version from the two-dimensional (2D) model which just lies on a flat surface. The heat transfer in the boundary layer flow have numerous applications in the production of polymer, plastic films, and paper production. Therefore, this paper solves 3D magnetohydrodynamics Newtonian fluid flow model with the effect of Soret-Dufour parameters. Compared with the previous report where the 3D model is without the inclination angle (all the axes are located at their fixed position), this paper considers the boundary xy-plane being projected by a certain angle from the z-axis. The initial partial differential equations (PDEs) are subsequently reduced to ordinary differential equations (ODEs). The MATLAB bvp4c program is chosen to solve the ODEs and the results velocity profile, temperature profile, concentration profile, skin friction coefficient, local Nusselt number, and local Sherwood number. It can be inferred that the magnetic parameter is responsible to the decrement of the velocity profile and skin frictions coefficient. The enhancement of the temperature and the local Sherwood number are caused by the Dufour number. Besides, concentration and the local Nusselt number are enhancing due to the increasing Soret number.
{"title":"The Soret-Dufour Effects on Three-Dimensional Magnetohydrodynamics Newtonian Fluid Flow over an Inclined Plane","authors":"Siti Suzilliana Putri Mohamed Isa, Hazirah Mohd Azmi, Nanthini Balakrishnan, Aina Suhaiza Mohamad Nazir, Kartini Ahmad, Nurul Syuhada Ismail, Norihan Md. Arifin, Haliza Rosali","doi":"10.37934/cfdl.16.9.3951","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.3951","url":null,"abstract":"The three-dimensional (3D) model of the fluid flow model with length, breadth, and height or depth is the advanced and precise version from the two-dimensional (2D) model which just lies on a flat surface. The heat transfer in the boundary layer flow have numerous applications in the production of polymer, plastic films, and paper production. Therefore, this paper solves 3D magnetohydrodynamics Newtonian fluid flow model with the effect of Soret-Dufour parameters. Compared with the previous report where the 3D model is without the inclination angle (all the axes are located at their fixed position), this paper considers the boundary xy-plane being projected by a certain angle from the z-axis. The initial partial differential equations (PDEs) are subsequently reduced to ordinary differential equations (ODEs). The MATLAB bvp4c program is chosen to solve the ODEs and the results velocity profile, temperature profile, concentration profile, skin friction coefficient, local Nusselt number, and local Sherwood number. It can be inferred that the magnetic parameter is responsible to the decrement of the velocity profile and skin frictions coefficient. The enhancement of the temperature and the local Sherwood number are caused by the Dufour number. Besides, concentration and the local Nusselt number are enhancing due to the increasing Soret number.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"83 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141011266","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}
Wong Kar Hao, Mohd Afzanizam Mohd Rosli, Jayaprakash Ponnaiyan, Safarudin Ghazali Herawan, Faridah Hussain
Hybrid solar drying chamber is an application that is widely used today for agriculture products because it can promise the hygiene of the product. However, drying chambers nowadays still lack uniformity in drying products within a drying chamber, leading to food wastage and compromised product quality. This study aims to design an innovative hybrid solar drying chamber system and investigate the uniformity of temperature and velocity within the chamber using Computational Fluid Dynamics (CFD). The methodology involves validating the simulation results by comparing them with existing journal data, with a validation error of less than 5%. A new design is proposed after the validation process, considering factors such as tray arrangement and air inlet size. The results show that a tray arrangement with 0.20 m spacing between each tray provides better uniformity in temperature and air velocity distribution compared to other arrangements. Additionally, an inlet size of 0.05 m2 demonstrates the most suitable temperature distribution for drying purposes, falling within the ideal range of 318 K to 343 K. The study showed that the performance of the drying chamber under different operating conditions has consistent temperature distribution and is suitable for uniform drying. Overall, the proposed hybrid solar drying chamber system offers improved temperature control and uniformity for effective drying process.
混合式太阳能干燥箱是当今广泛用于农产品的一种应用，因为它可以保证产品的卫生。然而，如今的烘干箱在烘干箱内烘干产品时仍然缺乏均匀性，导致食品浪费和产品质量下降。本研究旨在设计一种创新型混合太阳能干燥箱系统，并利用计算流体动力学（CFD）研究箱内温度和速度的均匀性。研究方法包括将模拟结果与现有的期刊数据进行对比验证，验证误差小于 5%。在验证过程后，考虑到托盘布置和进气口尺寸等因素，提出了新的设计方案。结果表明，与其他布置方式相比，每个托盘间距为 0.20 米的托盘布置方式能更好地实现温度和气流速度分布的均匀性。此外，0.05 平方米的进气口尺寸显示出最适合干燥目的的温度分布，在 318 K 至 343 K 的理想范围内。研究表明，干燥室在不同操作条件下的性能具有一致的温度分布，适合均匀干燥。总之，拟议的混合太阳能干燥箱系统可改善温度控制和均匀性，从而实现有效的干燥过程。
{"title":"A Simulation Study of Hybrid Solar Drying Chamber for Agriculture Product","authors":"Wong Kar Hao, Mohd Afzanizam Mohd Rosli, Jayaprakash Ponnaiyan, Safarudin Ghazali Herawan, Faridah Hussain","doi":"10.37934/cfdl.16.9.8193","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.8193","url":null,"abstract":"Hybrid solar drying chamber is an application that is widely used today for agriculture products because it can promise the hygiene of the product. However, drying chambers nowadays still lack uniformity in drying products within a drying chamber, leading to food wastage and compromised product quality. This study aims to design an innovative hybrid solar drying chamber system and investigate the uniformity of temperature and velocity within the chamber using Computational Fluid Dynamics (CFD). The methodology involves validating the simulation results by comparing them with existing journal data, with a validation error of less than 5%. A new design is proposed after the validation process, considering factors such as tray arrangement and air inlet size. The results show that a tray arrangement with 0.20 m spacing between each tray provides better uniformity in temperature and air velocity distribution compared to other arrangements. Additionally, an inlet size of 0.05 m2 demonstrates the most suitable temperature distribution for drying purposes, falling within the ideal range of 318 K to 343 K. The study showed that the performance of the drying chamber under different operating conditions has consistent temperature distribution and is suitable for uniform drying. Overall, the proposed hybrid solar drying chamber system offers improved temperature control and uniformity for effective drying process.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"54 51","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141010034","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}
Awaludin Martin, Mohammad Barbarosa, Fikri Fahlevi Nasution
The power plants in Indonesia are mostly used to supply energy for the industrial sector, including the upstream oil and gas as well as mining companies. Several companies operating in Riau contribute to the status of the region as the largest oil producer in Indonesia. These companies rely on self-generated electricity for their operations with subsequent impact on the environment. Therefore, this research was conducted to analyze the flow of energy, exergy, exergoeconomic, and environment at the 6 MW power plant operated by BOB - PT Bumi Siak Pusako - Pertamina Hulu. The second law of thermodynamics was used to evaluate energy efficiency as the maximum achievable effort. This was further integrated with economic principles to appraise the useful and wasted costs associated with thermodynamic systems through the concept of exergoeconomics. The results showed that the thermal efficiency of the gas turbine power plant was 42.85% and the exergy efficiency was 33.22% with the largest loss recorded in the combustion chamber to be 3.091 MW in the form of vibration, friction, or expansion of the components. It was also discovered that the exergy efficiency of each component was above 75%, thereby indicating the components of the gas turbine power plant components were in good condition. Moreover, the largest exergy destruction cost was 2349.16 USD/h and the exergy cost was 3,778.05 USD/kWh. The exhaust emission generated by the gas turbine power plant was 0.21 kg/s or equivalent to 0.1425 kg/kWh requiring a forest area of 11.63 ha. The results showed that the analytical method used could be comprehensively developed and applied to other power plants in Indonesia. It could also be used to understand system performance, identify energy losses, optimize energy efficiency, and link economic aspects with energy use.
印尼的发电厂主要用于为工业部门（包括上游石油和天然气以及采矿公司）提供能源。在廖内省运营的几家公司为该地区成为印尼最大的石油生产国做出了贡献。这些公司的运营依赖于自产电力，从而对环境造成了影响。因此，本研究对 BOB - PT Bumi Siak Pusako - Pertamina Hulu 运营的 6 兆瓦发电厂的能量流、放能、放经济和环境进行了分析。热力学第二定律被用来评估能源效率，即可实现的最大努力。这进一步与经济学原理相结合，通过努力经济学的概念来评估与热动力系统相关的有用成本和浪费成本。结果表明，燃气轮机发电厂的热效率为 42.85%，放能效率为 33.22%，燃烧室内因振动、摩擦或部件膨胀造成的最大损失为 3.091 兆瓦。研究还发现，每个组件的放能效率都高于 75%，这表明燃气轮机发电厂组件的状态良好。此外，最大的放能破坏成本为 2349.16 美元/小时，放能成本为 3778.05 美元/千瓦时。燃气轮机发电厂产生的废气排放量为 0.21 kg/s，相当于 0.1425 kg/kWh，需要 11.63 公顷的森林面积。结果表明，所使用的分析方法可以全面开发并应用于印度尼西亚的其他发电厂。该方法还可用于了解系统性能、确定能源损失、优化能源效率以及将经济方面与能源使用联系起来。
{"title":"Energy, Exergy, Exergoeconomic, and Environmental (4E) Analysis of the Existing Gas Turbine Power Plants in BOB - PT. Bumi Siak Pusako Pertamina","authors":"Awaludin Martin, Mohammad Barbarosa, Fikri Fahlevi Nasution","doi":"10.37934/cfdl.16.9.113","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.113","url":null,"abstract":"The power plants in Indonesia are mostly used to supply energy for the industrial sector, including the upstream oil and gas as well as mining companies. Several companies operating in Riau contribute to the status of the region as the largest oil producer in Indonesia. These companies rely on self-generated electricity for their operations with subsequent impact on the environment. Therefore, this research was conducted to analyze the flow of energy, exergy, exergoeconomic, and environment at the 6 MW power plant operated by BOB - PT Bumi Siak Pusako - Pertamina Hulu. The second law of thermodynamics was used to evaluate energy efficiency as the maximum achievable effort. This was further integrated with economic principles to appraise the useful and wasted costs associated with thermodynamic systems through the concept of exergoeconomics. The results showed that the thermal efficiency of the gas turbine power plant was 42.85% and the exergy efficiency was 33.22% with the largest loss recorded in the combustion chamber to be 3.091 MW in the form of vibration, friction, or expansion of the components. It was also discovered that the exergy efficiency of each component was above 75%, thereby indicating the components of the gas turbine power plant components were in good condition. Moreover, the largest exergy destruction cost was 2349.16 USD/h and the exergy cost was 3,778.05 USD/kWh. The exhaust emission generated by the gas turbine power plant was 0.21 kg/s or equivalent to 0.1425 kg/kWh requiring a forest area of 11.63 ha. The results showed that the analytical method used could be comprehensively developed and applied to other power plants in Indonesia. It could also be used to understand system performance, identify energy losses, optimize energy efficiency, and link economic aspects with energy use.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"359 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141006588","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 : 2024-05-06DOI: 10.37934/cfdl.16.9.114125
Md. Mustafa Kamal, Ali Abbas, Tabish Alam, Rohit Khargotra, Tej Singh
Flow streams in rivers, canals, and the tail race of a hydropower plant can be transformed into usable kinetic energy with the help of a hydrokinetic turbine. In this work, the torque characteristics of the hybrid turbine having Savonius helical blade angles of 0˚ and 180˚ have been evaluated using a numerical technique. The characteristics of the turbine are driven for the range of water speed of 0.5 to 2.0 m/s and TSR of 0.3 to 1.5. It is observed from numerical analysis that the flow speed of water significantly affects the mean torque and static torque established by the hybrid turbine. The torque developed by the hybrid turbine enhances as water speed increases. However, the structure of the Savonius blade can alter the torque characteristics of the turbine. The mean torque and static torque growth by the hybrid turbine with a Savonius helical blade angle of 0˚ is more optimum than the hybrid turbine with a Savonius helical blade angle of 180˚. Although, the positive magnitude of torque is achieved at every rotor angle over one revolution by introducing a twist angle to the traditional Savonius blade in the hybrid configuration.
{"title":"Influence of Water Flow Speed on the Torque Behaviour of the Hybrid HKT Having Straight and Helical Bladed Savonius Rotor","authors":"Md. Mustafa Kamal, Ali Abbas, Tabish Alam, Rohit Khargotra, Tej Singh","doi":"10.37934/cfdl.16.9.114125","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.114125","url":null,"abstract":"Flow streams in rivers, canals, and the tail race of a hydropower plant can be transformed into usable kinetic energy with the help of a hydrokinetic turbine. In this work, the torque characteristics of the hybrid turbine having Savonius helical blade angles of 0˚ and 180˚ have been evaluated using a numerical technique. The characteristics of the turbine are driven for the range of water speed of 0.5 to 2.0 m/s and TSR of 0.3 to 1.5. It is observed from numerical analysis that the flow speed of water significantly affects the mean torque and static torque established by the hybrid turbine. The torque developed by the hybrid turbine enhances as water speed increases. However, the structure of the Savonius blade can alter the torque characteristics of the turbine. The mean torque and static torque growth by the hybrid turbine with a Savonius helical blade angle of 0˚ is more optimum than the hybrid turbine with a Savonius helical blade angle of 180˚. Although, the positive magnitude of torque is achieved at every rotor angle over one revolution by introducing a twist angle to the traditional Savonius blade in the hybrid configuration.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"15 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141005883","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 : 2024-05-06DOI: 10.37934/cfdl.16.9.94113
Chethana G D, Sadashivegowda
Depending on specific needs and workloads, several racks with varied component densities may be used in a data center. As server density increases, porosity decreases, and the opposite is also true. A frequently used method called cold aisle containment separates hot air and cold air flows in data center settings to improve cooling effectiveness. In this paper, the performance of a data center is investigated using computational fluid dynamics, and the influence of porosity on cold aisle containment is evaluated using well-established non-dimensional performance parameters. The value of RTI without containment increased with an increase in porosity and a maximum RTI of 217 was found with a porosity of 0.75. Regardless of the rack number and porosity, containment provides the optimal RTI values. The results indicate that the SHI and RHI values for rack 1 for all porosities, without confinement, are outside of the permissible range and at higher porosities containment has no significant effects on SHI and RHI. RCILO values for racks 2, 3, and 4, with or without containment, fall within the 80-85% range, indicating temperatures below 13°C. RCIHI value is 1 for all cases considered indicating no rack is out of the recommended temperature of 25°C.
{"title":"A Comparative Numerical Study of Effectiveness of Cold Aisle Containment in Data Centers by Varying Rack Porosity Using Computational Fluid Dynamics","authors":"Chethana G D, Sadashivegowda","doi":"10.37934/cfdl.16.9.94113","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.94113","url":null,"abstract":"Depending on specific needs and workloads, several racks with varied component densities may be used in a data center. As server density increases, porosity decreases, and the opposite is also true. A frequently used method called cold aisle containment separates hot air and cold air flows in data center settings to improve cooling effectiveness. In this paper, the performance of a data center is investigated using computational fluid dynamics, and the influence of porosity on cold aisle containment is evaluated using well-established non-dimensional performance parameters. The value of RTI without containment increased with an increase in porosity and a maximum RTI of 217 was found with a porosity of 0.75. Regardless of the rack number and porosity, containment provides the optimal RTI values. The results indicate that the SHI and RHI values for rack 1 for all porosities, without confinement, are outside of the permissible range and at higher porosities containment has no significant effects on SHI and RHI. RCILO values for racks 2, 3, and 4, with or without containment, fall within the 80-85% range, indicating temperatures below 13°C. RCIHI value is 1 for all cases considered indicating no rack is out of the recommended temperature of 25°C.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"14 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141006022","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 : 2024-05-06DOI: 10.37934/cfdl.16.9.143177
Berlian Arswendo Adietya, Husein Syahab, Mahendra Indiaryanto, Wasis Dwi Aryawan, I Ketut Aria Pria Utama
Numerical analysis of fins effect on propeller performance was conducted, specifically using the B4-70 and Ka4-70 propellers. The study investigated different types of fins, including bare fins and PBCF (Propeller Boss Cap Fins) using computational fluid dynamics (CFD) simulations. The explicit algebraic stress model (EASM) based on Reynolds-Averaged Navier-Stokes (RANS) equations and turbulence modeling was employed to determine the optimal results. The main objective of this research was to enhance energy efficiency in ships by examining various open propeller configurations. The CFD simulation results for open propellers B4-70 and Ka4-70, with the addition of boss cap fins, revealed interesting phenomena. When the open propellers B4-70 and Ka4-70 were equipped with PBCF, they would experience an increase in efficiency (η0). This was because the performance of the fins functioned optimally when the advance ratio (J) is high, as evident from the high velocity values. Thus, with higher velocity and lower pressure in the boss cap region at high J values, there was an elevation in thrust force due to the reduction of hub vortex. In the case of open propeller B4-70 with added PBCF, there was an increase in the efficiency value (η0) ranging from 3% to 5% when J varied from 0 to 0.7. Similarly, for propeller Ka4-70 with the addition of PBCF, there was an increase in the efficiency value (η0) ranging from 1% to 3% when J varied from 0 to 0.7. Notably, the use of an Energy-Saving Device (ESD) in the form of PBCF can increase the efficiency of ship propeller, as reported in this paper. Consequently, these findings affirmed the reliability of the overall calculations using the CFD approach.
{"title":"Influence Evaluation of Open Propellers with Boss Cap Fins: Case Studies on Types B4-70 and Ka4-70","authors":"Berlian Arswendo Adietya, Husein Syahab, Mahendra Indiaryanto, Wasis Dwi Aryawan, I Ketut Aria Pria Utama","doi":"10.37934/cfdl.16.9.143177","DOIUrl":"https://doi.org/10.37934/cfdl.16.9.143177","url":null,"abstract":"Numerical analysis of fins effect on propeller performance was conducted, specifically using the B4-70 and Ka4-70 propellers. The study investigated different types of fins, including bare fins and PBCF (Propeller Boss Cap Fins) using computational fluid dynamics (CFD) simulations. The explicit algebraic stress model (EASM) based on Reynolds-Averaged Navier-Stokes (RANS) equations and turbulence modeling was employed to determine the optimal results. The main objective of this research was to enhance energy efficiency in ships by examining various open propeller configurations. The CFD simulation results for open propellers B4-70 and Ka4-70, with the addition of boss cap fins, revealed interesting phenomena. When the open propellers B4-70 and Ka4-70 were equipped with PBCF, they would experience an increase in efficiency (η0). This was because the performance of the fins functioned optimally when the advance ratio (J) is high, as evident from the high velocity values. Thus, with higher velocity and lower pressure in the boss cap region at high J values, there was an elevation in thrust force due to the reduction of hub vortex. In the case of open propeller B4-70 with added PBCF, there was an increase in the efficiency value (η0) ranging from 3% to 5% when J varied from 0 to 0.7. Similarly, for propeller Ka4-70 with the addition of PBCF, there was an increase in the efficiency value (η0) ranging from 1% to 3% when J varied from 0 to 0.7. Notably, the use of an Energy-Saving Device (ESD) in the form of PBCF can increase the efficiency of ship propeller, as reported in this paper. Consequently, these findings affirmed the reliability of the overall calculations using the CFD approach.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"15 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141007129","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}
Mohamed Ibren, A. D. Andan, W. Asrar, Dianne Binti Andan
Global concern about high noise levels in areas near airports and wind farms has generated interest from various groups due to factors such as potential health problems and dissatisfaction among the local community. To accommodate this worthwhile plan of further reducing overall noise levels, some researchers are working on lowering the contribution of trailing-edge noise. The original scientific contribution of this study lies on understanding the efficiency of various trailing edge designs such as baseline, serrations, comb and comb-serrated, across different angles of attack and Reynolds numbers, while also addressing the limitations of existing geometrical models for trailing edges. The study intends to examine the performance of these different configurations, with an emphasis on their effect on acoustic responses. By utilizing large-eddy simulation and applying the Ffowcs-Williams and Hawkings models for noise prediction, an investigation was conducted to assess the impact of these trailing edge configurations on radiated noise at a low Reynolds number of 1.6× 105. The numerical predictions of lift coefficient and surface pressure fluctuations are compared and validated with a published study and experimental data, showing satisfactory results. Further analysis of these study has demonstrated that prominent peaks at lower frequencies (<103) are observed, which are identified as the characteristic frequencies. Moreover, results showed irregular broadband noise (300 - 600 Hz) with increased noise and shifting peak frequency as angle of attack rose. The serrated trailing edge design notably reduced noise levels by roughly 21 dB, especially for low frequencies. Comb-serration increased high-frequency noise by about 9 dB for angles of attack at 0, -1, and -20, and achieved a reduction of approximately 9 dB for angles of attack at 1 and 20. On the other hand, the directivity pattern showed that the maximum noise level is observed to predominantly radiate at an azimuth angle of around 90 degrees for all the cases, ranging from 900 to 2700, indicating that the majority of the source's acoustic energy is being emitted on the suction and pressure sides of the airfoil.
{"title":"Numerical Prediction of Trailing Edge Noise at Low Reynolds Number with Modified Trailing Edges of a NACA 0015 Airfoil","authors":"Mohamed Ibren, A. D. Andan, W. Asrar, Dianne Binti Andan","doi":"10.37934/cfdl.16.8.6494","DOIUrl":"https://doi.org/10.37934/cfdl.16.8.6494","url":null,"abstract":"Global concern about high noise levels in areas near airports and wind farms has generated interest from various groups due to factors such as potential health problems and dissatisfaction among the local community. To accommodate this worthwhile plan of further reducing overall noise levels, some researchers are working on lowering the contribution of trailing-edge noise. The original scientific contribution of this study lies on understanding the efficiency of various trailing edge designs such as baseline, serrations, comb and comb-serrated, across different angles of attack and Reynolds numbers, while also addressing the limitations of existing geometrical models for trailing edges. The study intends to examine the performance of these different configurations, with an emphasis on their effect on acoustic responses. By utilizing large-eddy simulation and applying the Ffowcs-Williams and Hawkings models for noise prediction, an investigation was conducted to assess the impact of these trailing edge configurations on radiated noise at a low Reynolds number of 1.6× 105. The numerical predictions of lift coefficient and surface pressure fluctuations are compared and validated with a published study and experimental data, showing satisfactory results. Further analysis of these study has demonstrated that prominent peaks at lower frequencies (<103) are observed, which are identified as the characteristic frequencies. Moreover, results showed irregular broadband noise (300 - 600 Hz) with increased noise and shifting peak frequency as angle of attack rose. The serrated trailing edge design notably reduced noise levels by roughly 21 dB, especially for low frequencies. Comb-serration increased high-frequency noise by about 9 dB for angles of attack at 0, -1, and -20, and achieved a reduction of approximately 9 dB for angles of attack at 1 and 20. On the other hand, the directivity pattern showed that the maximum noise level is observed to predominantly radiate at an azimuth angle of around 90 degrees for all the cases, ranging from 900 to 2700, indicating that the majority of the source's acoustic energy is being emitted on the suction and pressure sides of the airfoil.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"89 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140736076","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：