组合发动机微细通道氦加热器设计与流动换热

氦加热器是预冷组合发动机中重要的换热器之一,其原理是利用燃气燃烧的热量提高氦气做功能力,进而提升整个循环系统运行效率.研究中首先设计了蛇形管式、瓦片式、辐射式三种微细通道氦加热器.其次,基于FLUENT15.0软件对微细通道氦加热器管内外的对流换热系数和流动阻力进行了研究.对比模拟结果和经典关联式的计算结果,确定了适用...

Design and flow heat transfer of mini-channel Helium heat exchanger in combined engine

Helium heat exchanger is one of the most important heat exchangers in Pre-Cooled Combined Engine.Helium heat exchanger can improve the working capacity of helium by utilizing the heat of gas to maintain system circulation.Firstly,three novel types of mini-channel heat exchangers with serpentine structures,tiled structures and radial structures were designed in this paper.Then,the flow and heat transfer performance of the novel mini-channel heat exchanger was analyzed based on the commercial software FLUENT15.0.The calculation formulas suitable for flow and heat transfer inside and outside tube of the mini-channel helium heat exchanger were examined by comparing simulation results with existing correlations.The results show that for the tube-inside,the existing classical correlations can calculate both convection heat transfer coefficient and flow resistance accurately with the average deviation below 8%.For the tube-outside,classical correlations can predict flow resistance accurately but the maximum deviation is close to 50%for the prediction of convection heat transfer coefficient in comparison with the simulation results.New correlations with average deviation less than 5%are fitted for tube-outside convective heat transfer of mini-channel helium heat exchanger.In addition,the proposed serpentine mini-channel helium heat exchanger achieves the highest convection heat transfer coefficient and comprehensive performance in the three heat exchangers.