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采用RNG k-ε湍流模型结合增强壁面处理的方法以及10组分替代模型对RP-3航空煤油在垂直上升圆管内的超临界对流换热进行了数值研究。详细分析了超临界条件下航空煤油的传热恶化机理,并将数值计算结果与常用经验换热公式值进行了比较,以考察这些经验关系式的适用性。计算结果表明:在较高的热流密度下,热物性的剧烈变化使径向流场产生异变,引发了复杂的传热恶化现象。其中,低主流焓值区的传热恶化是由热加速作用导致的,高主流焓值区的传热恶化是由径向速度波动造成的。Bae-Kim关系式能较好地反映垂直上升圆管中航空煤油的超临界传热情况,预测值与模拟值的相对误差均在20%以内;而Bishop等给出的经验公式则不再适用。
The RNG k-ε turbulence model combined with the enhanced wall treatment method and the 10-component alternative model were used to numerically study the supercritical convective heat transfer of RP-3 aviation kerosene in a vertically ascending tube. The mechanism of heat transfer deterioration of aviation kerosene under supercritical conditions is analyzed in detail. The numerical results are compared with the commonly used heat transfer formula values to investigate the applicability of these empirical relationships. The calculation results show that under the condition of high heat flux density, the drastic changes of thermal properties cause the radial flow field to change, leading to the complicated heat transfer deterioration. Among them, the deterioration of heat transfer in the low mainstream enthalpy area is caused by the thermal acceleration, and the heat transfer deterioration in the high mainstream enthalpy area is caused by the radial velocity fluctuations. The Bae-Kim relation can well reflect the supercritical heat transfer of aviation kerosene in vertical ascending tube, and the relative errors between the predicted and the simulated values are all within 20%. However, the empirical formulas given by Bishop et al. .