超（近）临界压力航空煤油RP-3的拟过冷沸腾传热特性

Pseudo Subcooled Boiling Heat Transfer Characteristics of Aviation Kerosene RP-3 under Super- and Near-Critical Pressure Conditions

关键词:  再生冷却  航空煤油  超临界  拟沸腾  传热恶化

Key words:  Regenerative cooling  Aviation kerosene  Supercritical  Pseudo-boiling  Heat transfer deterioration

摘要:

为了研究吸热型碳氢燃料在新型飞行器中的再生冷却性能，采用电加热方式，在热流密度0.1~1.0MW/m²和质量流速500~1000kg/（m²·s）条件下，小通道圆管内（D=1.6mm）研究了超（近）临界压力下（p=3MPa）航空煤油RP-3的拟沸腾流动传热特性。研究发现了超（近）临界压力航空煤油的拟过冷沸腾传热现象。拟过冷沸腾壁温变化特征和传热恶化特征与亚临界压力下的相应特征存在差异。超临界压力航空煤油传热区域划分为类液态强制对流传热区、拟过冷沸腾区和类气态强制对流传热区。拟过冷沸腾壁温和传热系数随流体温度升高而缓慢增加，起到传热强化的作用；拟临界温度区域，存在传热系数极小值点，燃料发生传热弱化；燃料温度高于拟临界温度，燃料处于超临界类气态，传热大幅强化。

Abstract:

In order to research the regenerative cooling performance of endothermic fuel in new vehicles， the pseudo-boiling heat transfer characteristics of super- and near-critical （p=3MPa） aviation kerosene RP-3 in an electrically heated small circular tube （Internal diameter D=1.6mm） were experimentally investigated at the operating conditions with heat fluxes of 0.1~1.0MW/m² and mass fluxes of 500~1000kg/（m²·s）. It found that a phenomenon of pseudo subcooled cooling boiling heat transfer occurred at super- and near-critical pressure conditions. But the wall temperature behaviors and heat transfer deterioration appearances in the process of pseudo-boiling have some differences from those at the subcritical pressure boiling conditions. The heat transfer characteristics of supercritical pressure aviation kerosene can be divided into three regions， including the liquid-like forced convection heat transfer， pseudo subcooled boiling heat transfer and gas-like forced convection heat transfer. During pseudo-boiling the wall temperature and heat transfer coefficient slowly increased with the increasing fluid temperature， and the heat transfer enhancement occurred. In the pseudo-critical temperature region， a heat transfer reduction existed with a minimum heat transfer coefficient value in the heat transfer curve. While the fuel temperature was above the pseudo-critical temperature， the fuel was at the supercritical gas-like condition and the heat transfer was greatly strengthened.