Journal of Thermal Engineering最新文献

Evaluation of the thermal efficiency of nanofluid flows in flat plate solar collector 评估平板太阳能集热器中纳米流体流的热效率

IF 1.1

Journal of Thermal Engineering Pub Date : 2024-01-02 DOI: 10.18186/thermal.1448578

Adnan M. Hussein, Afrah Awad, Hussein Hayder Mohammed Ali

{"title":"Evaluation of the thermal efficiency of nanofluid flows in flat plate solar collector","authors":"Adnan M. Hussein, Afrah Awad, Hussein Hayder Mohammed Ali","doi":"10.18186/thermal.1448578","DOIUrl":"https://doi.org/10.18186/thermal.1448578","url":null,"abstract":"In this research, flat plate solar collectors (FPSC) were studied due to their simplicity, low maintenance, and cost-effectiveness. The study focused on comparing FPSC thermal performance using CuO/H2O nanofluids. Experiments were conducted over three months during the Iraqi weather conditions (January, February, and March) with carefully selected nanoparticle concentrations. Data was collected from 9 A.M. to 3 P.M., using various mass flow rates (ranging from 0.003 to 0.076 kg/s). Results showed a direct correlation between temperature and nanoparticle concentrations, with the highest outlet temperature (50°C) observed at 3 P.M. for 1% CuO-water nanofluid. Notably, at 1 P.M. in March, the 1% CuO-water nanofluid exhibited a 32% increase in collector thermal efficiency, surpassing pure water by 11.3%. This would improve the performance of FPSC by achieving higher efficiency increments. These improvements were attributed to the unique physical properties of nanoparticles, their increased surface area, and higher thermal conductivity. The study determined that the optimum nanofluid concentration for superior collector efficiency was 1%.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140515598","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}

引用次数: 0

Experimental investigation of double-glazed double-pass solar airheater (DG-DPSAH) with multi-v ribs having trapezoidal roughness geometry 具有梯形粗糙几何形状的多v肋双层玻璃双通道太阳能空气加热器(dg - dpah)的实验研究

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1372390

Swati MOR, Niraj KUMAR, Gulshan SACHDEVA

{"title":"Experimental investigation of double-glazed double-pass solar airheater (DG-DPSAH) with multi-v ribs having trapezoidal roughness geometry","authors":"Swati MOR, Niraj KUMAR, Gulshan SACHDEVA","doi":"10.18186/thermal.1372390","DOIUrl":"https://doi.org/10.18186/thermal.1372390","url":null,"abstract":"In this study, roughness in the form of multi-V ribs having trapezoidal slots were crafted over the surface of absorber plate for enhancing the heat transfer rate in a solar air heater. An ex-perimental setup was designed and fabricated for demonstrating the performance of this plate with respect to smooth absorber plate. The setup has a double glazed-double pass air flow arrangement. The experiments were conducted under Indian climatic conditions (Latitude = 28.53˚N and Longitude = 77.39˚E) in September and October 2021 at various rates of air flow through the duct. The results of the roughened absorber plate were compared with the smooth absorber plate. It shows that the multi-V ribs with trapezoidal slots have higher efficacy as compared to smooth absorber plate in the order of 10.42% at an air flow rate of 0.078 kg/s. In addition, the present data of proposed roughness were also compared with data of various roughness available in the literature. It was found that the maximum thermo-hydraulic perfor-mance parameter of the proposed roughness texture is higher than other shapes of roughness texture. It was also found that the combination of double-glass cover and double-pass arrange-ment with the proposed roughness geometry increases the efficiency of the solar air heater at least by one order of the present solar air heating system.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944145","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}

引用次数: 0

Heat transfer enhancement and applications of thermal energy storage techniques on solar air collectors: A review 太阳能集热器强化传热及蓄热技术的应用综述

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1377246

Kafel AZEEZ, Riyadh Ibraheem AHMED, Zain Alabdeen OBAID, Itimad DJ AZZAWI

引用次数: 0

Parametric evaluation of solar integrated combined partial cooling supercritical CO2 cycle and Organic Rankine Cycle using low global warming potential fluids 利用低全球变暖势流体的太阳能集成部分冷却超临界CO2循环和有机朗肯循环的参数评价

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1370699

Yunis KHAN, Radhey Shyam MISHRA, Roshan RAMAN, Abdul Wahab HASHMI

{"title":"Parametric evaluation of solar integrated combined partial cooling supercritical CO2 cycle and Organic Rankine Cycle using low global warming potential fluids","authors":"Yunis KHAN, Radhey Shyam MISHRA, Roshan RAMAN, Abdul Wahab HASHMI","doi":"10.18186/thermal.1370699","DOIUrl":"https://doi.org/10.18186/thermal.1370699","url":null,"abstract":"In this study, the performance of the organic Rankine cycle combined with the partial cooling supercritical CO2 cycle as the bottoming cycle for recovering the low grade heat powered by a solar power tower was evaluated. Ecofriendly fluids were taken into consideration. To simulate the model under consideration, a computer programme was created in engineering equation solver software. The impacts of solar radiation, concentration ratio, solar incidence angle, CO2 turbine inlet temperature, heat exchanger effectiveness and main compressor inlet tempera-ture were investigated. Based on working fluid R1224yd(Z), it was determined that the com-bined cycle’s thermal efficiency, exergy efficiency, and power output improved from 35.16% to 55.43%, 37.73% to 59.42%, and 188 kW to 298.5 kW, respectively, as solar irradiation raised from 0.4 kW/m2 to 0.95 kW/m2. Lower the solar incidence angle and higher the concentration ratio can enhance the combined system’s performance. Amongst the working fluids that were taken into account, R1224yd(Z) was suggested as having superior performance.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944814","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}

引用次数: 0

Heat transfer model for dropwise condensation on hydrophobic and superhydrophobic interfaces 疏水和超疏水界面水滴凝结传热模型

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1374673

R. YUVARAJ, D. SENTHILKUMAR

{"title":"Heat transfer model for dropwise condensation on hydrophobic and superhydrophobic interfaces","authors":"R. YUVARAJ, D. SENTHILKUMAR","doi":"10.18186/thermal.1374673","DOIUrl":"https://doi.org/10.18186/thermal.1374673","url":null,"abstract":"Heat transfer models for condensation on hydrophobic and superhydrophobic interfaces are broadly available based on thermal resistance correlations. In the previous studies, very few models are presented based on the scaling factor or Nusselt number, and no model is available that directly correlates Biot number. This study develops a heat transfer model for dropwise condensation underneath a horizontal surface. The present model correlates with the Biot number to predict the heat transfer, temperature variation at the interfaces, solid-liquid, and liquid-vapor, and the growth rate of droplet condensate on the hydrophobic and superhydro-phobic interfaces by using Archimedes’ hat-box theorem. The present model is validated with analytical and experimental results against hydrophobic and superhydrophobic contact angles of similar working parameters made excellent agreements. The analytical model for dropwise condensation produces inaccurate results due to discrepancies and discontinuities due to mul-tiple correlations in the modeling. The present model is modified to obtain a continuous result using experimental data. The modified model is used for analyzing heat transfer by varying Biot numbers from 0.0001 to 1000 using Python 3.6.1 with an accuracy of 10-4. Simulation of the present model results in constant heat transfer at Bi = 4, irrespective of the contact angle. A negligible amount of coating resistance and interface resistance when Bi > 0.1, curvature effect when Bi > 0.04, droplet resistance when Bi < 0.02, the maximum liquid-vapor interface tem-perature at Bi ≈ 10, and maximum solid-liquid interface temperature at Bi ≈ 5, are presented.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135945149","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}

引用次数: 0

Experimental evaluation of the effect of leakage in scroll compressor 涡旋压缩机泄漏影响的实验评价

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1372348

Niyaj Dilavar SHIKALGAR, Shivalingappa Nagappa SAPALI

引用次数: 0

Effect of heat flux and mass flux on the heat transfer characteristics of supercritical carbon dioxide for a vertically downward flow using computational fluid dynamics and artificial neural networks 利用计算流体力学和人工神经网络研究超临界二氧化碳垂直向下流动时热流通量和质量通量对传热特性的影响

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1376850

Rajendra PRASAD K S, Vijay KRISHNA, Sachin BHARADWAJ

{"title":"Effect of heat flux and mass flux on the heat transfer characteristics of supercritical carbon dioxide for a vertically downward flow using computational fluid dynamics and artificial neural networks","authors":"Rajendra PRASAD K S, Vijay KRISHNA, Sachin BHARADWAJ","doi":"10.18186/thermal.1376850","DOIUrl":"https://doi.org/10.18186/thermal.1376850","url":null,"abstract":"Drastic variation in the thermodynamic properties of supercritical fluids near the pseudo critical point hinders the use of commercial computational fluid dynamics (CFD) software. However, with the increase in computational abilities, along with the use of Artificial Neu-ral Networks (ANN), turbulence heat transfer characteristics of supercritical fluids can be very accurately predicted. In the present work, heat transfer characteristics for a vertically downward flow of carbon dioxide in a pipe are studied for a wide range of heat flux and mass flux values. Firstly, six different turbulent models available in the commercial CFD software - Ansys Fluent are validated against the experimental results. The k- ω Standard model with enhanced wall treatment is found to be the best-suited turbulence model. When experimental results were validated in CFD, an average error of 1% in the bulk fluid temperature and 2% in the wall temperature were recorded. Further, K- ω Standard Turbulence Model is used in CFD for parametric analysis to generate the data for ANN studies. Mass flux range of 238 to 1038 kg/m2s, and heat flux range of 26 kW/m2 to 250 kW/m2 are used to generate 81,432 data sam-ples. These samples were fed into the ANN program to develop an equation that can predict the heat transfer coefficient. It was found that ANN can predict the heat transfer coefficient for the considered range of values within the absolute average relative deviation of 2.183 %.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944496","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}

引用次数: 0

An exploratory review on heat transfer mechanisms in nanofluid based heat pipes 纳米流体热管传热机理的探索性综述

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1377230

Udayvir SINGH, Harshit PANDEY, Naveen Kumar GUPTA

引用次数: 0

Experimental investigation for the decisive role of vehicles in the air pollution of arak city in Iran and presenting the related solutions to reduce the air pollution 对伊朗阿拉克市大气污染中车辆的决定性作用进行了实验调查，并提出了减少大气污染的相关解决方案

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1376802

Seyyed Alireza MOSTAFAVI, Hamed SAFIKHANI, Hasan KÖTEN, Yasin KARAGOZ

{"title":"Experimental investigation for the decisive role of vehicles in the air pollution of arak city in Iran and presenting the related solutions to reduce the air pollution","authors":"Seyyed Alireza MOSTAFAVI, Hamed SAFIKHANI, Hasan KÖTEN, Yasin KARAGOZ","doi":"10.18186/thermal.1376802","DOIUrl":"https://doi.org/10.18186/thermal.1376802","url":null,"abstract":"In the World, in many of the large and industrial cities air quality is in a dire situation, and air pollution is considered a major problem. The first step in reducing the level of pollutants is to acquire enough detailed information about these pollutants, including the type, amount, and the rate of annual occurrence. In this study, the data obtained from the existing air quality measuring stations throughout the city of Arak in Iran have been used to conduct an accurate investigation and to perform hourly, daily, monthly, and annual analyses of various pollutants. The hourly analysis of the data collected from the Shariati square station at the downstream of the prevailing wind, which include the collective pollutions of the refinery, petrochemical plant, thermal power plant and the pollution generated by the vehicles in a high-traffic area, with regards to the annual calendar and the variation of pollutants during official holidays, indicates the determining share of vehicles in the air pollution of the city of Arak. Considering the effective role of vehicles in the extensive air pollution of this city, some policies have been suggested for reducing the level of air pollution. As a result of this study, using the stated transportation model the level of pollution in this city is considered to reduce, correcting the city streets and routes from engineering per-spective. Also, results showed that the role of industry and vehicles on the air pollution and the pollution points in Arak city in ratio. The levels of all the pollutants like CO, NOx, PM2.5, O3 and SO2 measured by a station at the downstream and resulted about 3ppm, 20ppb, 10, 40ppb and 4 as a ratio respectively. Lastly, result of model was reported at the end of this paper in term of the optimization of the Arak city residential area.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944498","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}

引用次数: 0

Extended experimental investigation of a double-effect active solar still with a paraffin wax, in Owerri, Nigeria 在尼日利亚奥韦里，用石蜡进行双效活性太阳能蒸馏器的扩展实验研究

Journal of Thermal Engineering Pub Date : 2023-10-17 DOI: 10.18186/thermal.1374686

Ernest C. NWOSU, Kelechi NSOFOR, Godswill N. NWAJI, Chibuike ONONOGBO, Ikechi OFONG

{"title":"Extended experimental investigation of a double-effect active solar still with a paraffin wax, in Owerri, Nigeria","authors":"Ernest C. NWOSU, Kelechi NSOFOR, Godswill N. NWAJI, Chibuike ONONOGBO, Ikechi OFONG","doi":"10.18186/thermal.1374686","DOIUrl":"https://doi.org/10.18186/thermal.1374686","url":null,"abstract":"In this work, an experiment-based study of a double-effect, single-slope active solar still (SSASS) is presented. The system comprises an upper and a lower basin incorporated with a paraffin wax acting as a phase change material (PCM). The use of phase change materials is very important due to their high storage density and the isothermal nature of the storage pro-cess. Paraffin wax was selected based on its attractive thermo-physical properties. The thermal behaviours of the system during the diurnal and nocturnal phases in both compartments were explored. Experimental results showed that the upper basin’s yield contributed more to the overall distillate production over a 24-hour cycle while that of the lower basin predominated the diurnal production. Though the PCM served as an energy source during the nocturnal phase, it did not translate to significant improvement in the yield of the lower basin. The heat retention ability of the lower glazing retarded the condensation of the humid air in the lower compartment during the off-sunshine period. Thus, the nocturnal yield of the system was largely driven by the improved temperature difference between the upper saline water and the upper glazing, as well as the stored thermal energy in the saline water mass before sunset. The system achieved a maximum yield of 2,450 ml/day and a yield rate of 232.5 ml/h. A maximum monthly average yield of 1,787 ml/day was realized in May and a minimum of 692 ml/day in July. Nocturnal distillate production accounted for an average of 55% of the total distillate recovered from the still daily. The system achieved an efficiency range of 12.20 - 32.21%. The cost of freshwater production from the system is estimated at 0.0508 $/L with a payback period of 267 days. Thus, this system is economically viable and suitable particularly, for low-income earners.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135945148","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}

引用次数: 1