{"title":"THERMO-HYDRAULIC CHARACTERISTICS OF ADDITIVELY MANUFACTURED MINI-CHANNELS","authors":"А.А. Khalatov, І.І. Borisov, S. Kulishov","doi":"10.31472/ttpe.2.2023.3","DOIUrl":null,"url":null,"abstract":"The aim of this work is to analyze the heat transfer, hydraulic resistance and thermo-hydraulic performance of a new type of heat exchange channels made by additive technology. The main factors affecting the quality of products and determining the heat transfer and hydraulic resistance of the channels are noted. Well-known ratios for calculating hydraulic resistance and heat transfer are not suitable for such high roughness. Data on the AT resistance coefficient of the channels show that even at low Reynolds numbers there is a contribution of roughness. With increasing roughness, the intensification of resistance and heat exchange increases. The transition occurs at 700 < Re < 2000. Comparison of data on heat transfer augmentation and increase of hydraulic losses, as well as their thermo-hydraulic characteristics has been carried out. The hydraulic resistance coefficient of AT channels is significantly higher than the resistance coefficient of smooth channels. Heat transfer augmentation in wave-shaped channels is 2 times higher than augmentation in straight channels. Channels with pin fins allow to achieve a very high heat transfer augmentation (up to 8). Channels with internal grids provide high intensification, but have the highest hydraulic losses. The dependence of the Reynolds analogy factor on the resistance increase factor showed that the straight channels of all geometric forms fit on one dependence closed to the lower boundary line, and have a low hydraulic resistance. Data on channels with pin fins have a large spread. A number of points are above the upper boundary line, which refers to channels with low surface roughness. ","PeriodicalId":23079,"journal":{"name":"Thermophysics and Thermal Power Engineering","volume":"88 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2023-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Thermophysics and Thermal Power Engineering","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.31472/ttpe.2.2023.3","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
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Abstract
The aim of this work is to analyze the heat transfer, hydraulic resistance and thermo-hydraulic performance of a new type of heat exchange channels made by additive technology. The main factors affecting the quality of products and determining the heat transfer and hydraulic resistance of the channels are noted. Well-known ratios for calculating hydraulic resistance and heat transfer are not suitable for such high roughness. Data on the AT resistance coefficient of the channels show that even at low Reynolds numbers there is a contribution of roughness. With increasing roughness, the intensification of resistance and heat exchange increases. The transition occurs at 700 < Re < 2000. Comparison of data on heat transfer augmentation and increase of hydraulic losses, as well as their thermo-hydraulic characteristics has been carried out. The hydraulic resistance coefficient of AT channels is significantly higher than the resistance coefficient of smooth channels. Heat transfer augmentation in wave-shaped channels is 2 times higher than augmentation in straight channels. Channels with pin fins allow to achieve a very high heat transfer augmentation (up to 8). Channels with internal grids provide high intensification, but have the highest hydraulic losses. The dependence of the Reynolds analogy factor on the resistance increase factor showed that the straight channels of all geometric forms fit on one dependence closed to the lower boundary line, and have a low hydraulic resistance. Data on channels with pin fins have a large spread. A number of points are above the upper boundary line, which refers to channels with low surface roughness.
本文分析了一种新型增材制造的换热通道的传热特性、水力阻力和热工性能。指出了影响产品质量和决定通道传热和水力阻力的主要因素。众所周知的计算水力阻力和传热的比率不适用于如此高的粗糙度。通道的AT阻力系数数据表明,即使在低雷诺数下,粗糙度也有贡献。随着粗糙度的增加,阻力和热交换的强度增加。转变发生在700 < Re < 2000。比较了换热增大和水力损失增大的数据,以及它们的热液特性。AT通道的水力阻力系数明显高于光滑通道的阻力系数。波浪形通道的换热增益比直线通道的换热增益高2倍。带有销鳍的通道可以实现非常高的传热增强(高达8)。带有内部网格的通道提供高强化,但具有最高的水力损失。雷诺数类比因子对阻力增加因子的依赖关系表明,所有几何形式的直流道在靠近下边线的一项依赖关系上都符合,并且具有较低的水力阻力。带销钉鳍的通道的数据有很大的传播。许多点位于上边界线之上,这是指表面粗糙度较低的通道。