尾喷管超临界氢再生冷却传热数值模拟研究

Numerical simulation of supercritical hydrogen regeneration cooling heat transfer in tail nozzle

中文关键词: 超临界氢，再生冷却，数值模拟，传热恶化，参数影响

英文关键词: Supercritical hydrogen, regenerative cooling, numerical simulation, heat transfer deterioration, parameter effects

中文摘要:

      针对航空发动机尾喷管再生冷却过程，开展了超临界氢在中等热流密度下流动换热的数值模拟研究。再生冷却通道截面形状为圆形，内径为1.6 mm。设计点工况氢质量流量为0.44 g/s,压力为8 Mpa，进口温度30 K，通道下壁面热流密度为345 Kw/m2。采用RNG k-ε湍流模型和增强壁面处理的方法，探究了超临界氢在通道内的速度，温度等参数分布，以及传热系数的变化规律。通过改变系统压力，热流密度和通道肋厚度，进一步探究了上述因素对超临界氢再生冷却过程中的流动换热造成的影响，并重点关注了传热恶化现象的产生。结果表明：在设计点工况下并未产生传热恶化现象，只有入口效应导致的对流换热系数降低；减小系统压力和增加壁面热流密度都会导致传热恶化现象的出现，而减小通道肋厚度会造成对流换热系数有轻微的降低。

英文摘要:

      A numerical simulation study was conducted on the flow and heat transfer of supercritical hydrogen under moderate heat flux for the regeneration cooling process of aircraft engine tail nozzles. The cross-sectional shape of the regenerative cooling channel is circular, and the inner diameter is 1.6 mm。At the design point, the mass flow rate of hydrogen is 0.44 g/s and the pressure is 8 Mpa, the inlet temperature is 30 K, and the heat flux on the lower wall of the channel is 345 Kw/m2. the RNG k-ε turbulence model combined with enhanced wall treatment were used to explore the distribution of velocity, temperature and other parameters of supercritical hydrogen in the channel, as well as the variation curves of heat transfer coefficient. By changing the system pressure, heat flux and channel rib thickness, the influence of the above factors on flow and heat transfer during supercritical hydro-gen regeneration cooling was further explored, and the heat transfer deterioration was emphasized. The results show that the heat transfer deterioration doesn’t occurs under the design point condi-tions, and only the convective heat transfer coefficient decreases caused by the inlet effect. Decreas-ing the system pressure and increasing the wall heat flux will lead to heat transfer deterioration, while decreasing the thickness of the channel ribs will lead to a slight decrease in the convective heat transfer coefficient.