Journal of Thermal Science and Engineering Applications最新文献_第5页

Numerical study on thermo-hydraulic performance of enhanced tube with crossed helical dimples 交叉螺旋凹窝强化管热工性能数值研究

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-25 DOI: 10.1115/1.4063044

Jiyu Zheng, Zheng Liang, Liang Zhang, Y. Qiu, JiaWei Zhou, Zhongchao Yan

{"title":"Numerical study on thermo-hydraulic performance of enhanced tube with crossed helical dimples","authors":"Jiyu Zheng, Zheng Liang, Liang Zhang, Y. Qiu, JiaWei Zhou, Zhongchao Yan","doi":"10.1115/1.4063044","DOIUrl":"https://doi.org/10.1115/1.4063044","url":null,"abstract":"\u0000 A numerical investigation was performed to study the thermo-hydraulic performance in an enhanced tube with crossed helical dimples. The simulations were carried out in the Reynolds number range of 5000-30000 in crossed helical dimple tube of a period length with a constant wall temperature of 350K. The thermal enhancement, friction factor and performance evaluation criteria were the primary focus of the present work. Moreover, geometric parameters such as spiral pitch, transverse length and dimple depth were investigated for their effects on thermo-hydraulic performance. The results revealed that the shape of crossed helical dimple exerts positive effects on the heat transfer enhancement. This unique shape generated intensive transverse flow and induced a higher transverse velocity, leading to heat transfer enhancement. Therefore, the synthesized heat transfer performance was increased by 150% - 225% over that of the smooth tube. Furthermore, the heat transfer enhancement and friction factors increased with increasing dimple depth and declining spiral pitch and transverse length. Within the scope of this study, the maximum PEC = 2.25 was observed for Re = 30000, P = 30 mm, L = 11.064 mm, and H = 3 mm.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"21 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80837933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Attack angle parametrization for capacity augmentation and wake management by vortex generators in finned compact heat exchangers 翅片式紧凑型换热器涡发生器增容和尾迹管理的攻角参数化

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-25 DOI: 10.1115/1.4063046

A. Arora, P. Subbarao

{"title":"Attack angle parametrization for capacity augmentation and wake management by vortex generators in finned compact heat exchangers","authors":"A. Arora, P. Subbarao","doi":"10.1115/1.4063046","DOIUrl":"https://doi.org/10.1115/1.4063046","url":null,"abstract":"\u0000 Enhancing gas-side thermal conductance is essential for the compact sizing of finned-tube heat exchangers, and this study attempts it by integrating vortex generators. The orientation of the vortex generators, which is defined by its attack angle, has a strong bearing on the degree of augmentation. As energy-efficiency keeps varying with the attack angle, the thrust of this investigation is to identify best attack angle(s) for the stipulated task. Since spatial positioning of the generators too has a strong bearing on the energy-efficiency, therefore, its effect is duly accounted for a comprehensive investigation. For the selection of optimal designs, regression-based phenomenological models are used as they apply thermo-hydraulic trade-off. After determining the best angle(s), a study is carried out to evaluate their robustness under varying operating conditions. Although phenomenological models are adequate for design optimization, they do not describe the physics of thermo-hydraulic enhancement. Therefore, a study explaining the bearing of design modifications on the local characteristics too is carried out. Additionally, a study discussing the effect of generators' attack angle on heat transfer over the wake affected surfaces, which has a predominant existence in baseline flows, is reported. It has been found that the thermal augmentation over the said surfaces is the key to compact sizing of the system. For a selected wake-region deployment, the highest relative Colburn j-factor corresponding to wake-affected fin equals 3.07 at a specified Reynolds number..","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"126 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78561027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study of thermal hydraulic performance improvement in solar air heater channel with V-shaped porous baffles v型多孔折流板改善太阳能空气加热器热工性能的实验研究

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-25 DOI: 10.1115/1.4063043

Mohamed Tahar Baissi, S. Hassani, Hesseyn Karoua, Kamel Aoues, M. Noureddine

引用次数: 1

Effects of Performance and Normalized parameters on various materials based Multistage Thermoelectric Generator 不同材料基多级热电发电机性能及归一化参数的影响

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-20 DOI: 10.1115/1.4062999

Kartik Srivastava, R. Sahoo

{"title":"Effects of Performance and Normalized parameters on various materials based Multistage Thermoelectric Generator","authors":"Kartik Srivastava, R. Sahoo","doi":"10.1115/1.4062999","DOIUrl":"https://doi.org/10.1115/1.4062999","url":null,"abstract":"\u0000 Multi-staging and variable cross-section significantly improve the performance of thermoelectric generators. Hence, the present theoretical study analyses a multistage variable-shaped thermoelectric generator (MVS TEG) for a combination of dissimilar materials. Effect on voltage, power, conversion efficiency, normalized constraints (voltage, energy, and conversion efficiency), and second law efficiency with a row number, exhaust inlet temperature, and the coolant flow rate have been investigated. Results reveal that the row number is the most critical input parameter, followed by exhaust inlet temperature and coolant flow rate. Also, the work gives optimum values of rows for voltage and power as Nx=19 for MVS TEG-1, MVS TEG-3, and MVS TEG-4 while Nx=18 for MVS TEG-2. The exhaust inlet temperature variation increases the voltage and power output by 54 to 59% and 53 to 58%, respectively. The coolant flow variation has a more significant impact on the conversion efficiency, and the average improvement in the efficiency is about 9.23% in the present study. The second law efficiency decreases with the increase in all the input parameters.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"29 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76234769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Study on thermal-hydraulic characteristics of novel channels for printed circuit heat exchanger using supercritical CO2 超临界CO2热交换器新型通道热水力特性研究

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-20 DOI: 10.1115/1.4062998

He Yang, Jinduo Li, Huimin Wei, Xiaoze Du, Hongwei Wu

{"title":"Study on thermal-hydraulic characteristics of novel channels for printed circuit heat exchanger using supercritical CO2","authors":"He Yang, Jinduo Li, Huimin Wei, Xiaoze Du, Hongwei Wu","doi":"10.1115/1.4062998","DOIUrl":"https://doi.org/10.1115/1.4062998","url":null,"abstract":"\u0000 Two new types of PCHE channels are proposed based on typical airfoil fin PCHE channel proposed in literatures (standard channel) to further improve the thermal-hydraulic performances of airfoil fin PCHE channel. The small shuttle fins and oval fins are employed between the adjacent two airfoil fins of two novel channels, respectively. Using supercritical CO2 as the working fluid, the thermal-hydraulic performances and enhancement mechanisms of the novel channels are numerically investigated. The results show that the channel with shuttle fins has the best comprehensive performance. The Nusselt number of the channel with shuttle fins is 6.7–26% larger, and the f factor is 8.3–18.6% larger than that of the standard channel under the selected conditions, which leads to a 3–19.1% increase in the PEC (comprehensive performance evaluation criteria). The Nusselt number of the channel with oval fins is 9–27.3% larger, and the f factor is 26.6–43.4% larger than that of the standard channel, which leads to a 1–15.3% increase in the PEC. The applications of small fins between the adjacent two fins can effectively reduce the low-velocity region area and enhance the local disturbance, thereby effectively improving the thermal-hydraulic performance. The enhancement mechanism of the novel fin PCHE channel structure can be well explained by the principle of field synergy. It can be found that the synergies of the temperature gradient field and the velocity field in two novel channels are significantly improved.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"72 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84496436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study and simulation of thermal conductivity of saturated frozen soil 饱和冻土导热系数的实验研究与模拟

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-18 DOI: 10.1115/1.4062975

Zhifeng Ren, Enliang Wang, Jiankun Liu

{"title":"Experimental study and simulation of thermal conductivity of saturated frozen soil","authors":"Zhifeng Ren, Enliang Wang, Jiankun Liu","doi":"10.1115/1.4062975","DOIUrl":"https://doi.org/10.1115/1.4062975","url":null,"abstract":"\u0000 The aim of this study was to enhance the accuracy of predicting the temperature field of frozen soil and to reduce the workload of thermal parameter testing. To achieve this, we employed a three-phase model comprising soil, water, and ice. The unfrozen water content in frozen soil at varying temperatures was determined using nuclear magnetic resonance spectroscopy (NMR), while the thermal conductivity was measured by a thermal characteristic analyzer. A MATLAB software-based random model of the frozen soil was then established and imported into COMSOL simulation software. The repeatability and reproducibility of the established model were verified by varying the proportions of pore water and frozen ice to determine the degree of simulation accuracy.The results demonstrated that the unfrozen water content maintained a dynamic equilibrium relationship with temperature, which influenced the thermal conductivity of frozen soil. The simulation results were consistent with those obtained from instrument measurements of trends with respect to temperature. The average PBIAS value between the calculated and measured values was 0.0139, indicating theoretical feasibility. Comparison with experimental data confirmed the effectiveness of our approach, providing a novel concept and a simple method for predicting the temperature field of frozen soil engineering in areas that experience seasonal freezing.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"41 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85237321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

How to Plot Heatlines? 如何绘制标题?

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-12 DOI: 10.1115/1.4062954

C. Mukherjee, S. Mukhopadhyay

{"title":"How to Plot Heatlines?","authors":"C. Mukherjee, S. Mukhopadhyay","doi":"10.1115/1.4062954","DOIUrl":"https://doi.org/10.1115/1.4062954","url":null,"abstract":"\u0000 In non-isothermal flows, heatlines are used to depict the energy flow from a hot surface to a cold surface, and helps in visualising the strength of the convective heat transfer as compared to the conductive heat transfer. Traditionally, researchers have plotted heatlines by solving heat-function equations in their solvers during the runtime. However, this requires access to the solver code and is time consuming to implement. Further, the literature available so far only concerns simple geometric shapes. This work aims to document out-of-the box methods for visualization of heatlines that can be done as a post-processing exercise. A comparison of streamlines and heatlines, is first presented to enhance the understanding of the application of heatlines in heat transfer problems and to use the same technique in post-processing computer programs for visualizing heatlines. The procedures to plot heatlines using commercial (TecPlot and CFD-Post) and open-source (ParaView) tools are presented. Illustrative examples of different computational geometries from past literature are validated to establish the efficacy of the method. Further, the method can be also applied to plot heatlines for complex geometries which is not feasible with the traditional approaches","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"97 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89916828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermodynamic and Thermo - economic Analysis of a Solar Integrated Double Turbine Kalina Cycle for varying Solar Flux Conditions 不同太阳通量条件下太阳能集成双涡轮Kalina循环的热力学和热经济分析

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-10 DOI: 10.1115/1.4062922

Devi Parvathy S, James Varghese

{"title":"Thermodynamic and Thermo - economic Analysis of a Solar Integrated Double Turbine Kalina Cycle for varying Solar Flux Conditions","authors":"Devi Parvathy S, James Varghese","doi":"10.1115/1.4062922","DOIUrl":"https://doi.org/10.1115/1.4062922","url":null,"abstract":"\u0000 Kalina cycle is established as a reliable low-grade energy cycle working on solar, geothermal and other waste heat recovery sources. This work aims to develop a novel methodology for optimizing a Kalina cycle according to the solar irradiation. A comprehensive analysis of performance is conducted by varying the parameters of the Kalina system, modeled with high and low pressure turbines. The present work implements and analyses the performance of a multi turbine Kalina cycle with cylindrical parabolic collectors for energy input at different time, on a particular day, for a location. The proposed cycle is modeled to simulate the working. The dependency of parameters - separator pressure, concentration of ammonia in boiler, intermediate separator temperature and vapor fraction at condenser side turbine exit - on the system performance is investigated. Optimization is conducted using genetic algorithm with net power as objective function for different solar irradiations. The optimized power values are 282.62, 246.75, 222.31 and 180.0 kW for solar influxes 507.7, 461.8, 413.9 and 321.0 W/m 2 respectively. The results show that the proposed model can be adopted for better performance. A thermo – economic analysis of an optimized output is conducted to conclude on capital investment and operation cost for sustainable power production. The analysis yields highest cost rate of exergy destruction of 58936.41$/yr for the boiler. The investment cost the turbines together is 89% of the total capital investment and hence thermo - economic factor is highest for these components.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"76 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86438652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Computational assessment of a novel solar calciner 一种新型太阳分解炉的计算评价

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-10 DOI: 10.1115/1.4062921

M. Syrigou

引用次数: 0

Effect of Working Fluid, Orientation and Cooling Mode on Thermal Performance of Miniature Flat Heat Pipe 工作流体、取向和冷却方式对微型平板热管热工性能的影响

IF 2.1 4区工程技术

Journal of Thermal Science and Engineering Applications Pub Date : 2023-07-10 DOI: 10.1115/1.4062920

J. Rathod, V. Lakhera, A. Shukla

{"title":"Effect of Working Fluid, Orientation and Cooling Mode on Thermal Performance of Miniature Flat Heat Pipe","authors":"J. Rathod, V. Lakhera, A. Shukla","doi":"10.1115/1.4062920","DOIUrl":"https://doi.org/10.1115/1.4062920","url":null,"abstract":"\u0000 Flat Heat Pipes (FHP) are commonly used as passive cooling system in portable electronic gadgets due to their compact profile. The present study investigates the effect of different working fluids on the thermal performance of a miniature flat heat pipe (FHP) under different orientations and condenser cooling mechanisms. Deionized (DI) water, acetone, ethanol, and methanol are chosen as working fluids in the FHP. Five different inclinations (0° (Horizontal), 30°, 45°, 60° and 90° (Vertical)) and two different condenser cooling methods (natural convection and forced convection with fan cooling) are considered in this experimental study. The FHP thermal performance is quantified in terms of overall temperature difference, thermal resistance, and effective thermal conductivity. The results indicate that comparatively higher effective thermal conductivity values are obtained for methanol and acetone heat pipes at low heat loads and under natural convection. At higher heat loads, the ethanol heat pipe had higher effective thermal conductivity values for the same condenser cooling method. For the case of forced convection cooling mode, the methanol heat pipe had enhanced thermal performance as compared to the other three fluids for all heat load ranges and different inclinations. Due to the higher boiling point of water, as a working fluid water is not suitable in most of the experimental trials except at high heat load under forced convection cooling and in a horizontal orientation.","PeriodicalId":17404,"journal":{"name":"Journal of Thermal Science and Engineering Applications","volume":"55 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83769895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0