Journal of Enhanced Heat Transfer最新文献

{"title":"INVESTIGATION ON THE EFFECT OF OSCILLATING MAGNETIC FIELDS ON FLUID FLOW AND FORCED-CONVECTION HEAT TRANSFER AROUND A SPHERE","authors":"Zeinab Abbasi, A. Dehkordi","doi":"10.1615/jenhheattransf.v30.i5.50","DOIUrl":"https://doi.org/10.1615/jenhheattransf.v30.i5.50","url":null,"abstract":"In this article, the heat transfer of magnetic nanofluids over a sphere has been considered in the presence of an external oscillating uniform magnetic field for a wide range of Reynolds number values (Re). This study incorporates the effect of magnetic permeability and purposes the optimal operating condition for the first time. The significant difference between the magnetic property of the nanofluid and the heated sphere makes a non-uniform magnetic field around the sphere resulting in a significant alteration in the distribution of velocity and temperature around sphere. The variations of average Nusselt number (Nuavg) and drag coefficient (Cd) have been studied to demonstrate the influence of magnetic field frequency and intensity, Re, and the relative magnetic permeability of the sphere. It has been found that the magnetic field causes the vortices to appear or grow behind the sphere. This leads to fluid separation even for low Re values in the presence of magnetic field. Local Nu value is minimum at the separation point. This point moves towards the front of sphere as the magnetic field intensity increases. These vortices lead to boundary layer distortion, thereby increasing heat-transfer rate and drag force. In addition, the obtained results clearly indicate that there is an optimal frequency at which Nuavg and Cd can be maximized. The dimensionless optimal frequency (Ωτ) is about 0.6 regardless of Re value or magnetic field intensity. Moreover, the influence of the applied magnetic field is more noticeable for low Re values and/or frequencies near the optimum value. For instance, Nuavg and Cd increase by 150% and 50%, respectively, for Re value of 30 while they are three times smaller for Re value of 200. Increase in the magnetic permeability of sphere enhances the Nuavg up to 170% (at Re = 50) close to the optimal frequency, whereas its effect is almost negligible for frequencies far away from the optimal one. Furthermore, the obtained results clearly demonstrate that the heat-transfer increase is much larger than the penalty due to the drag force increase for frequencies close to the optimal value.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82619812","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}

{"title":"Prediction of Heat Transport and Drag Force of Ferrofluids around a Sphere in the Presence of Oscillating Magnetic Field","authors":"Zeinab Abbasi, A. Dehkordi","doi":"10.1615/jenhheattransf.2023046945","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023046945","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72534650","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}

{"title":"Simulation of the cold end temperature and the optimal current of thermoelectric cooler with variable semiconductor cross-section","authors":"Jimin Xu, Tianwang Lai, Xiangyang Liu, Maogang He","doi":"10.1615/jenhheattransf.2023048408","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023048408","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76233847","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}

{"title":"EXPERIMENTAL INVESTIGATIONS ON EFFECTIVENESS FOR COMBINED IMPINGEMENT FILM COOLING","authors":"R. Panda, Arun Pujari, B. Gudla","doi":"10.1615/jenhheattransf.2023047457","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023047457","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79927444","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}

{"title":"Revving up heat transfer performance of double pipe heat exchanger using diverse molar Ag-GO hybrid nanofluids: An Empirical and Numerical study using Central Composite Design","authors":"Armstrong M, Sivasubramanian M, Selvapalam N, Rajaganapathy C","doi":"10.1615/jenhheattransf.2023048558","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023048558","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90111567","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}

{"title":"Experimental and Numerical Study On Solar Energy Storage in Black-Covered Sunspace Using Water-Filled Tin Cans","authors":"Faraz Afshari, Emre Mandev, Burak Muratçobanoğlu, Ali çelik, Mehmet Akif Ceviz","doi":"10.1615/jenhheattransf.2023048545","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023048545","url":null,"abstract":"In this study, it is aimed to store solar energy in a sunspace room for energy saving in cold regions by using water-filled tin cans. The energy collected in the water during the sunbathing hours is transferred to the environment in the evening when the ambient air temperature suddenly drops. Additionally, in the sunspace area, the walls were covered with black material and by absorbing more solar radiation inside the room, the heating performance was evaluated. In addition to experimental studies, ANSYS Fluent software (2022 R1 version) as a computational fluid dynamics (CFD) program has been used to simulate the sunspace domain in analyses. According to the results obtained, while there was a sudden drop in temperature in the ambient air after sunset, it was observed that the water temperatures in the tin cans decreased more slowly. This indicates that heat transfer from the tin cans to the ambient air occurs during the night times. In addition, the effect of black surface application was shown and the differences between indoor and outdoor temperatures were evaluated. While the average temperature difference between the indoor and outdoor environment during the sunshine period without the black surface was 4.67 °C, this difference reached 9.53 °C in the case of the black surface. The maximum energy efficiency was obtained when black surface was used, and this value was recorded as 58.2%.","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135561319","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}

{"title":"Influence of natural convection on comprehensive effective thermal conductivity of the anisotropic open-cell foam","authors":"Chao Zhang, Xian Wang, Hui Wang, Yanxia Du, G. Xiao","doi":"10.1615/jenhheattransf.2023048970","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023048970","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85409169","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}

{"title":"Development of Heat Exchangers with 2-pass Diverging Microchannels for Evaporation Cooling Systems","authors":"Kuan-Fu Sung, Cheng-Hung Hsu, Chien-Yuh Yang","doi":"10.1615/jenhheattransf.2023048705","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023048705","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84827181","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}

{"title":"Molecular study of core-shell ratio effect on thermophysical properties of SiO2@Au-water nanofluid","authors":"S. Noraldeen, L. Jin, Leping Zhou","doi":"10.1615/jenhheattransf.2023046713","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023046713","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83123691","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}

{"title":"Sensitivity analysis and optimization of wavy fin circular tube heat exchanger","authors":"M. Bardalai","doi":"10.1615/jenhheattransf.2023045738","DOIUrl":"https://doi.org/10.1615/jenhheattransf.2023045738","url":null,"abstract":"","PeriodicalId":50208,"journal":{"name":"Journal of Enhanced Heat Transfer","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73845790","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}