Journal of Thermal Engineering最新文献

{"title":"Simulation of heat transfer and effectiveness in a helical heat exchanger made from thermally enhanced polymer material for use in absorption cooling","authors":"T. Ahmadu, Hamisu Adamu DANDAJEH1","doi":"10.18186/thermal.1297545","DOIUrl":"https://doi.org/10.18186/thermal.1297545","url":null,"abstract":"Heat exchangers in absorption chillers are usually made of copper material. However, prob-lems of corrosion are usually encountered, especially in the solution heat exchanger. In this study a numerical investigation of the heat transfer effectiveness in a double pipe helical heat exchanger made from a thermally enhanced polymer material was conducted. The material consists of a Liquid crystal polymer (LCP), (Vectra A950) as the matrix material, while carbon fibre is the filler material. The resulting composite has a carbon fibre weight fraction of 74%. The heat exchanger was modelled as a counter flow solution heat exchanger to be used in a lithium bromide – water absorption chiller of 3 kW capacity. The numerical software ANSYS fluent (version 14.5) was used for the modelling and simulation. Thermal and mechanical properties of the thermally enhanced polymer were used in the modelling and simulation. The viscous laminar model was used, while employing a second order upwind solution method. Results indicate that the heat exchanger was able to perform the required duty by reducing the strong solution temperature from 90oC at inlet to 57oC at outlet, while increasing the weak solution temperature from 40oC at inlet to 67oC at outlet. The effectiveness of the heat ex-changer was 77.4%. Results were numerically compared to a corresponding heat exchanger of same geometry and flow conditions, made of copper. It was observed that the polymer heat exchanger attained 89.2% effectiveness of the copper heat exchanger.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49291441","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}

{"title":"Design, development, and analysis of a box type solar cooker with optimally reflecting side walls","authors":"H. Vaidya, M. Rathod, S. Channiwala","doi":"10.18186/thermal.1297564","DOIUrl":"https://doi.org/10.18186/thermal.1297564","url":null,"abstract":"A novel inclined sidewall box-type solar cooker is constructed, and its performance is evalu-ated. The Opto-geometrical design of the cooker was designed for Surat, a city in India. The design is modified by optimizing the inclination angles of the sidewalls so that an optimal thermal response may be generated by reflecting sun rays from the sidewalls, and the perfor-mance of the solar cooker is enhanced. The optimized sidewall angles due south, due north, due east, and due west are designed to be 67.30, 22.690, 35.440, and 35.440, respectively and side walls are made reflective with reflecting Aluminium sheets. The results are compared with a conventional cooker. The thermal performance of the newly built solar cooker was evaluated, and the merit F1 for no-load circumstances and the merit F2 for various loading conditions were determined. The results show that the maximum plate temperature, the figure of merit F1, and the maximum pot temperature of the newly developed solar cooker with optimally reflecting sidewalls during load test are higher than that of a conventional cooker. The max-imum plate temperature is found to be 760C and 650C in newly designed and conventional solar cookers, respectively. The temperatures are found to be about 16% more from 11:30 pm to 2:00 pm in the newly designed cooker compared to the conventional cooker. The maximum value of Figure of merit F1 is found to be 0.15 and 0.11 in newly designed and conventional solar cookers. The maximum value of Figure of merit F2 is found to be 0.59 and 0.30 in newly designed and conventional solar cookers. The maximum value of pot temperature is found to be 860C and 600C for newly designed and conventional solar cookers, respectively, during the load test, which is about 43% more in the newly designed cooker than the conventional cooker. The highest cooking temperature in the newly designed cooker was maintained at 90 0C for about 2 hours, and that in the conventional cooker was maintained at 60 0C for about 2 hours. In addition, the cooking test demonstrates that the food is thoroughly cooked in the newly built solar cooker, while it was discovered undercooked in the conventional cookerC thickness, respectively without heat recovery. The operating conditions and optimized geo-metric factors, based on result analysis and comparison, are discussed in detail.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42134401","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}

{"title":"A numerical investigation on thermal analysis of RPC based solar thermochemical reactor for two-step H2O splitting cycle for hydrogen production","authors":"Jeet Sharma, R. Jilte, Ravinder Kumar","doi":"10.18186/thermal.1297556","DOIUrl":"https://doi.org/10.18186/thermal.1297556","url":null,"abstract":"Ceria based solar thermochemical cycle is a high-temperature based redox chemical reactions to split H2O or CO2to produce hydrogen and/or syngas. The redox reactions are carried out in a reactor cavity thus the analysis and optimization of design as well as thermal analysis is a crucial factor to improve the solar-to-fuel conversion efficiency. This paper proposes the hybrid design of cylindrical and hemispherical cavity and its effects of geometrical parame-ters such as reticulated porous ceria (RPC) thickness (15 mm, 20 mm, and 25 mm) and gas flow gap (5 mm&10 mm) on temperature and flux distribution and solar-to-fuel efficiency for both steady-state and transient condition. A numerical computational fluid dynamics (CFD) analysis is carried out to study heat and mass transfer as well as geometrical design consid-eration of the STCR cavity under SolTrace generated Gaussian distributed concentrated solar flux. Two-step water-splitting reaction in the Solar Thermochemical cavity reactor (STCR) using ceria (CeO2) has been modeled to explore the oxygen evolution/reaction rate and to estimate solar-to-fuel efficiency and its relationship with geometrical factors. The RPC of 25 mm thickness yields the highest oxygen evolution rate of 0.34 mL/min/gCeO2 and solar-to-fuel efficiencies are 7.82%, 12.07% and 16.18% for 15 mm, 20 mm and 25 mm of RPC thickness, respectively without heat recovery. The operating conditions and optimized geometric factors, based on result analysis and comparison, are discussed in detail.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41360757","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}

{"title":"Flow of viscous nanofluids across a non-linear stretching sheet","authors":"P. K. Pattnaik, S. Syed, Sujogya Mishra, S. Jena, Sachindar Kumar Rout, K. Muduli","doi":"10.18186/thermal.1296280","DOIUrl":"https://doi.org/10.18186/thermal.1296280","url":null,"abstract":"This article aims to demonstrate the flow of viscous nanofluid over a non-linear stretching sheet. Considering thermal radiation and dissipative heat in the heat transport phenomenon encourages the flow properties. In generally, nanofluids are employed in heat transfer equip-ment because they improve the thermal characteristics of coolants present in the equipment. Additionally, these fluids possess unique features that have the potential to be applied in a variety of applications, such as pharmaceutical procedures, hybrid power engines, household refrigerators, grinding, and microchips, among others. Consequently, the current model is built to allow for the optimal selection of thermophysical parameters such as conductivity and viscosity, which will enhance the overall effectiveness of the study. Appropriate transfor-mation rules have been used to modify the highly non-linear PDEs into a couple of highly non-linear ODEs. An efficient built-in MATLAB bvp5C algorithm addresses the boundary value problem under consideration. Using the dimensionless parameters assumed in the prob-lem, changes in the velocity as well as the temperature profiles are shown, and rate coefficients, by using numerical simulations are also employed in tabular form. The important outcomes which are exposed in the study are; that the particle concentration is used as a controlling pa-rameter to reduce the nanofluid velocity, whereas it favours enhancing the fluid temperature and the radiating heat along with the coupling parameter due to the inclusion of dissipative heat also encourages to overshoot the temperature profile.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48411965","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}

{"title":"Assessment of ec-toxicity potential of fuel by exhaust gas analysis","authors":"Aezeden Mohamed, Paul Kuri, S. Rout, K. Muduli","doi":"10.18186/thermal.1295910","DOIUrl":"https://doi.org/10.18186/thermal.1295910","url":null,"abstract":"The engine combustion products were measured and analyzed based on emissions of exhaust. Due to the utilization of a variety of fuels, such as petroleum diesel and bio-diesel in diesel- generated engines, they emit pollution-insecure emissions. To explore this emission quantity, a numbers of experiments were conducted utilizing a single-cylinder engine, Land Curser six-cylinder, Mazda WL31 engine mechanical biodiesel vehicle and In-Line engine. The performance research was given for the data acquired from the Mazda WL31 four-cylinder \u0000engine. Landcom III gas analyzer was used to sense and record the exhaust gas emissions from the burning of diesel fuel, which was utilized for data analysis. Various gas discharges and their constituents were independently analyzed. The results of the test show that the harmful","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47564725","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}

{"title":"Performance comparison of basic and parallel double evaporator Organic Rankine Cycle integrated with solar based supercritical CO2 cycle","authors":"Yunis Khan, Radhey SHYAM MISHRA","doi":"10.18186/thermal.1293026","DOIUrl":"https://doi.org/10.18186/thermal.1293026","url":null,"abstract":"Performance comparison of basic organic Rankine cycle (ORC) and parallel double evapora-tor ORC (PDORC) integrated with solar power tower (SPT) driven intercooled cascade sCO2 (supercritical carbon dioxide) cycle was carried out in present study. The intercooled cascade sCO2 cycle/ORC (configuration-1) and the intercooled cascade sCO2 cycle/PDORC (configu-ration-2) were considered for comparison on basis of parametric analysis. The effects of SPT design parameters such as solar irradiation, solar receiver emittance, and concentration ratio on system performance were investigated. It was concluded that the addition of basic ORC and PDORC to the intercooled cascade sCO2 cycle improved the thermal efficiency by 2.26% and 6.66% respectively at solar irradiation of 950 W/m2. In the case of basic ORC and PDORC, the waste heat recovery ratios were 0.1197 and 0.1775, respectively. It was also discovered that configuration-2 performed better than configuration-1 in terms of waste heat recovery. The combined cycle’s performance can be improved even more by lowering solar emittance and increasing the concentration ratio.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49242620","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}

{"title":"Influence of nano additives on performance and emissions characteristics of a diesel engine fueled with watermelon methyl ester","authors":"Arunprasad Prasad, Rajkumar Sivanraju, Aklilu Teklemariam, Dawit Tafesse, Mebratu Tufa, Bovas Herbert Bejaxhin","doi":"10.18186/thermal.1285915","DOIUrl":"https://doi.org/10.18186/thermal.1285915","url":null,"abstract":"Significant population and automobile expansion have resulted in a rapid rise in energy demand. Because of the high demand for energy and the rapid depletion of fossil fuels, experts are concentrating their efforts on developing a suitable alternative fuel for diesel. The performance and emission characteristics of biodiesel made from watermelon methyl ester were investigated using a lanthanum oxide (La2O3) nanoparticle addition. Through the transesterification meth od, biodiesel was produced from non-edible watermelon seed oil. Compared to B20, addition of 100 parts per million (ppm) of La2O3 nanoparticles to biodiesel emulsion fuel reduces CO and HC emissions by 4.75% and 6.67%, respectively. Compared to B20 at full load circumstances, the inclusion of La2O3 nanoparticles at 100 ppm enhances the brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) by 2% and 8.8%, respectively.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48934100","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}

{"title":"Application of exergy analysis in understanding the performance of a coal-fired steam power plant (120 mw) with single reheat and regenerative configuration","authors":"S. Arpit, Praveen kumar, P. K. Das, S. Dash","doi":"10.18186/thermal.1285229","DOIUrl":"https://doi.org/10.18186/thermal.1285229","url":null,"abstract":"In the present paper, a rigorous analysis of a sub-critical steam power plant (120 MW) with reheating and regenerative configuration is presented, using energy and exergy analysis. The total work output from the power plant is 121.80 MW, which is close to the real value of 120 MW. The calculated energy efficiency of the steam power plant is 34.7%, while its exergy efficiency is 32%. In addition to it, energy analysis introduces the condenser as a major source of heat loss, on other hand, exergy analysis introduces the boiler as a major source of exergy destruction. Further to understand the effect of main steam temperature, reheating temperature and condenser pressure on the power plant, a parametric study is being conducted.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47027588","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}

{"title":"A CFD investigation of flow separation in an elliptical and circular Ranque-Hilsch vortex tube","authors":"N. Bagre, A. Parekh, V. Patel","doi":"10.18186/thermal.1285134","DOIUrl":"https://doi.org/10.18186/thermal.1285134","url":null,"abstract":"The present work investigates the flow physics inside an elliptical vortex tube. Two different 3D (three-dimensional) domains of circular and elliptical vortex tubes with four nozzles are studied. The cross-sectional area and length of the vortex tube are constant for both of its shape. The pressure at the inlet is 320 kPa for both the shapes and air as a working fluid. Standard k- ε turbulence model is used to predict the flow physics and temperature separation effect inside the tubes. The experimental and numerical findings of earlier researchers provide as validation for the present results. The deviation of the results is found within the permissible limit. The temperature separation phenomenon in an elliptical tube at various cold mass fractions is discussed. The range of cold mass fraction is 0.1 to 0.9. This work also examines the fluid characteristics and flow parameters by tracing the fluid particles within the tube. Fluid characteristics such as static pressure, density, total temperature, static temperature are evaluated. Also, the flow parameters like velocity magnitude, turbulent kinetic energy, axial velocity, and swirl velocity are discussed at the various radial locations inside the tube to get the flow pattern information. It’s an attempt to determine the feasible flow mechanism inside an elliptical vortex tube. The comparison between the circular vortex tube and the elliptical vortex tube has been done based on various fluid characteristics and temperature separation. It is found that energy separation is elevated in an elliptical tube by 49.89% at the hot end tube at 0.2 cold mass fraction whereas it is low for cold temperature separation as compared to the circular vortex.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42205884","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}

{"title":"Experimental investigation of nanofluids for heat pipes used in solar photovoltaic panels","authors":"Bisma Ali, A. Qayoum, S. Saleem, Fasil Qayoum Mir","doi":"10.18186/thermal.1285179","DOIUrl":"https://doi.org/10.18186/thermal.1285179","url":null,"abstract":"The current study is aimed to measure and analyze the impact of temperature (10°C < T < 90°C) and particle concentration (0.05% < ϕ < 1.5%) on thermo-physical properties of TiO2, ZnO and CuO nanoparticles suspended in Therminol-55. The nanoparticles were characterized by using various techniques, including TEM, XRD, FTIR, TGA/DSC. TEM images reveal that the morphology of TiO2 and ZnO as spherical nanoparticles whereas that of CuO is in the form of flakes. XRD pattern for TiO2, ZnO and CuO nanoparticles possess anatase, heaxagonal and monoclinic phase respectively. TGA results show that that TiO2 losses less mass than the ZnO and CuO nanoparticles at each stage of decomposition. Thereby making it more stable thermally as compared to the other samples. Two-step method has been employed to formulate stable Therminol-55 based nanofluids containing TiO2, ZnO and CuO nanoparticles for varying particle concentrations. Results show that the thermal conductivity of suspensions containing solid conducting particles increase with increasing nanoparticle content and temperature of dispersions in the fluid. The thermal conductivity of TiO2/Therminol-55, ZnO/Therminol-55 and CuO/Therminol-55 nanofluids increases up to 17.62%, 21.55% and 24.32% at particle concentration of 1.5 wt%. Further, the experimental results demonstrate that the density of nanofluids increased significantly with increase in concentration and decreased with temperature. Surface tension of nanofluids shows decrease with increase in particle concentration. This indicates that adding nanoparticles improve thermo-physical properties of nanofluid, making it suitable for use in heat pipe. The measured data for thermal conductivity and density are compared with existing theoretical models of nanofluids to check the effectivity of conventional models. A multi-variable new generalized correlations for thermal conductivity and density of Therminol-55 based nanofluids containing TiO 2, ZnO and CuO nanoparticles are proposed.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42402453","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}