超临界压力下航空煤油传热特性

Heat transfer characteristics of kerosene in micro-channelunder supercritical pressure

关键词:  超临界压力  煤油  传热特性  强化  恶化

Key words:  Supercritical pressure  Kerosene  Heat transfer characteristics  Enhancement  Deterioration

摘要:

为了弄清航空煤油在超临界压力下的传热情况,进行了超临界压力下航空煤油传热实验研究。由实验结果绘出了超临界压力下煤油传热曲线图。实验结果表明:煤油在超临界压力下传热情况从低温到高温依次历经四个过程:(1)正常传热段, 这一段内实验管内壁温和煤油温度都低于临界温度；(2)传热强化段,这一段内管内壁温度达到拟临界温度,发生拟沸腾强化传热；(3)传热恶化段,这一段内煤油温度处于临界温度附近比热和导热系数都迅速达到极大值之后的缓慢减小区段；(4)第二次传热强化段,这一段是经过传热恶化后,随着温度的进一步升高,比热和导热系数又缓慢升高,出现第二次传热强化。

Abstract:

The heat transfer of the kerosene under supercritical pressure was investigated through experiment. According to the experimental results, the heat transfer curve of the kerosene under supercritical pressure was plotted. The results show that kerosene heat transfer under supercritical pressure from low to high temperature goes through the following four periods:(1) the normal heat transfer:in this region, the tube wall temperature and the kerosene temperature are lower than the critical temperature; (2) heat transfer enhancement period:in this region, the tube wall temperature arrives at the critical temperature, similar boiling heat transfer happened; (3) heat transfer deterioration:in this region, the temperature is higher than the temperature that the specific heat reaches the maximum value and decreases slowly after the maximum; (4) the second heat transfer enhancement:after the heat transfer deterioration period, when the temperature is even higher,both the specific heat and the conduction coefficient rises slowly, and the second heat transfer enhancement come.