复合型微细通道换热器的流动传热特性研究

Study on Flow and Heat Transfer Performance of Mini-channel Heat Exchanger

预冷器作为高超声速预冷发动机的关键部件之一,需要在极短时间内对高温空气进行快速冷却,其流动传热性能对预冷发动机性能具有重要影响。本文根据预冷器两侧流体流量和工作压力差异大的特点,提出了一种复合型微细通道换热器。数值模拟研究结果表明,沿着低温氦气流动方向,低温氦气与高温空气的温度及对流换热系数逐渐增大,并且在Z=130 mm之后的变化明显大于之前的变化;增大空气侧的质量流量会增大空气侧和氦气侧的压降,而增大氦气侧的质量流量会减小空气侧的压降,单位体积的换热功率会随着两侧质量流量的增加而增大。

As one of the key components in the hypersonic precooling engine,the precooler should reduce the temperature of hot air in a very short time,and its flow and heat transfer performance has an important impact on the performance of the precooled engine.In this paper,a new type of hybrid printed circuit heat exchanger is proposed in view of the large differences in the two-side mass fow rates and working pressures in the precooler.The numerical results show that along the flow direction of low-temperature helium,the temperature and convective heat transfer coefficient of low-temperature helium and high-temperature air increase gradually,and the change after Z-130 mm is obviously greater than the previous change.Increasing the mass fow on the air side increases the pressure loss on the air and helium sides.However,increasing the helium-side mass fow reduces the air-side pressure drops.The heat transfer rate per unit volume increases with the increase of the mass flow on both sides.