基于Zukauskas关系式的预冷发动机进气道流动特性研究

Flow characteristics of a type of precooled engine inlet based on Zukauskas correlation

关键词:  预冷发动机进气道  Zukauskas关系式  宽速域  横掠管束  预冷特性

Key words:  Precooled engine inlet  Zukauskas correlation  Wide-velocity range  Cross tube bundle  Pre-cooling characteristics

摘要:

为了研究预冷发动机进气道流动特性，以二维变几何轴对称进气道为研究对象，利用Zukauskas横掠管束绕流关系式，对进气道流场展开了数值仿真研究，探究预冷器的冷却效应及换热管直径对进气道流场、性能的影响。结果表明：Zukauskas关系式能较好地预测气流在预冷器管束间的流动损失；经过预冷后，涡轮通道总温大幅下降，但总温分布不均匀，温度梯度明显，对流换热对上游流体总温产生的影响很小；在Ma_∞=2~5飞行工况下，换热功率随着飞行马赫数的增加而增大，涡轮通道的出口总温较预冷前降低了22%~60%，出口马赫数降低了17%~51%，反压比增加了10%~26%，总压恢复系数增加了3%~8%；当预冷器的管径从1 mm增大至2.5 mm时，涡轮通道出口速度降低了16.5%，反压比降低了1%，总压恢复系数呈现先下降后上升的趋势。将虚拟预冷器管束排布方式改为顺排，预冷器的换热功率下降，出口总温上升，涡轮通道的出口速度上升了11%~30%。

Abstract:

To study the flow characteristics of a precooled engine inlet， the two-dimensional axisymmetric inlet with variable geometry was taken as the research object， the numerical investigation of the inlet was carried out by using Zukauskas correlation of flow across tube bundle， the cooling effects of precooler and the influence of diameter of heat exchange tube on inlet flow field and performance were explored. The results show that Zukauskas Correlation can better predict the flow loss of the precooler tube bundles. After precooling， the total temperature of the turbine channel decreases significantly， but the total temperature distribution is nonuniform， the temperature gradient is obvious， and the convection heat transfer has little effect on the total temperature of the upstream fluid. In Ma_∞=2~5 flight conditions， the heat transfer power increases with the increase of flight Mach number. The outlet temperature of the turbine channel decreases by 22%~60%， the outlet Mach number decreases by 17%~51%， the back pressure ratio increases by 10%~26% and the total pressure recovery coefficient increases by 3%~8%. When the tube diameter of the precooler increases from 1 mm to 2.5 mm， the outlet velocity of the turbine channel decreases by 16.5%， the back pressure ratio decreases by 1%， and the total pressure recovery coefficient has an ascent after an initial decline trend. By changing the arrangement of the virtual precooler tubes bundle to in-line arrangement， the heat transfer power of the precooler decreases， the total outlet temperature increases， and the outlet speed of the turbine channel increases by 11%~30%.