{"title":"Corrugated circular dimple absorber for heat transfer augmentation on parabolic trough solar receiver","authors":"","doi":"10.1016/j.icheatmasstransfer.2024.108041","DOIUrl":null,"url":null,"abstract":"<div><div>Corrugated circular dimple absorber <span><math><mo>(</mo></math></span>CCD<span><math><mo>)</mo></math></span> as a heat transfer augmentation is introduced for line focusing solar receiver. It is designed to increase heat transfer performance with minimal increase of pressure drop. Meanwhile, computational fluid dynamics (CFD) analysis which is widely used is conducted by using ANSYS software to study outlet working fluid temperature, absorber temperature distribution, Nusselt number, specific heat loss, specific pressure drop and performance evaluation criteria (PEC). Heat transfer working fluid is Syltherm 800, a thermal oil which is extensively utilized in concentrating solar thermal power plant. The mass flow rate values are between 0.3 kg/s and 4 kg/s, the inlet temperatures of working fluid are 375 K and 650 K and concentrated heat flux is 100,000 W/m<span><math><msup><mrow></mrow><mn>2</mn></msup></math></span>. At 375 K inlet working fluid temperature, simulation results showed that corrugated circular dimple absorber can improve outlet working fluid temperature up to 8 K over 4 m absorber length and performance evaluation criteria reaches 3.28. This energy gain is obtained from lower specific heat loss to ambient due to higher Nusselt number. Increasing inlet working fluid temperature to 650 K will reduce thermal energy output since the specific heat loss increases from 137 W/m to 644 W/m due to radiation at higher temperature and emissivity value. Nusselt number rises from 230 to 521 and maximum absorber temperature decreases from 1036 K to 970 K. The specific pressure drop rises from 11 Pa/m in a smooth absorber to 41 Pa/m in a corrugated circular dimple absorber due to surface changes, but the performance evaluation criteria is at 1.31. In conclusion, CCD design can improve heat transfer performance with minimum pressure drop penalty indicated by higher PEC values.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":null,"pages":null},"PeriodicalIF":6.4000,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0735193324008030/pdfft?md5=4d9fb295f11990e2a4277edc4fd4a95d&pid=1-s2.0-S0735193324008030-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Communications in Heat and Mass Transfer","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0735193324008030","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MECHANICS","Score":null,"Total":0}
引用次数: 0
Abstract
Corrugated circular dimple absorber CCD as a heat transfer augmentation is introduced for line focusing solar receiver. It is designed to increase heat transfer performance with minimal increase of pressure drop. Meanwhile, computational fluid dynamics (CFD) analysis which is widely used is conducted by using ANSYS software to study outlet working fluid temperature, absorber temperature distribution, Nusselt number, specific heat loss, specific pressure drop and performance evaluation criteria (PEC). Heat transfer working fluid is Syltherm 800, a thermal oil which is extensively utilized in concentrating solar thermal power plant. The mass flow rate values are between 0.3 kg/s and 4 kg/s, the inlet temperatures of working fluid are 375 K and 650 K and concentrated heat flux is 100,000 W/m. At 375 K inlet working fluid temperature, simulation results showed that corrugated circular dimple absorber can improve outlet working fluid temperature up to 8 K over 4 m absorber length and performance evaluation criteria reaches 3.28. This energy gain is obtained from lower specific heat loss to ambient due to higher Nusselt number. Increasing inlet working fluid temperature to 650 K will reduce thermal energy output since the specific heat loss increases from 137 W/m to 644 W/m due to radiation at higher temperature and emissivity value. Nusselt number rises from 230 to 521 and maximum absorber temperature decreases from 1036 K to 970 K. The specific pressure drop rises from 11 Pa/m in a smooth absorber to 41 Pa/m in a corrugated circular dimple absorber due to surface changes, but the performance evaluation criteria is at 1.31. In conclusion, CCD design can improve heat transfer performance with minimum pressure drop penalty indicated by higher PEC values.
期刊介绍:
International Communications in Heat and Mass Transfer serves as a world forum for the rapid dissemination of new ideas, new measurement techniques, preliminary findings of ongoing investigations, discussions, and criticisms in the field of heat and mass transfer. Two types of manuscript will be considered for publication: communications (short reports of new work or discussions of work which has already been published) and summaries (abstracts of reports, theses or manuscripts which are too long for publication in full). Together with its companion publication, International Journal of Heat and Mass Transfer, with which it shares the same Board of Editors, this journal is read by research workers and engineers throughout the world.