航空发动机旋转帽罩结冰表面换热系数研究

Numerical Simulation of Heat Transfer Coefficient on Icing Surface of Rotating Cone in Aero-Engine

关键词:  航空发动机  旋转帽罩  对流换热系数  关联式

Key words:  Aero-engine  Rotating cone  Heat transfer coefficient  Correlation

摘要:

旋转帽罩表面的对流换热系数是结冰、防冰研究的重要参数，旋转帽罩结冰模拟中对流换热量和蒸发量都需要已知对流换热系数。为了获取旋转帽罩表面的对流换热系数，采用数值模拟对旋转帽罩结冰表面的对流换热系数进行了研究。首先验证了网格与计算方法的合理性和可靠性，在此基础上，对影响表面换热的因素进行了分析，计算了不同转速、来流速度、来流温度对锥角40°，锥高176mm的旋转帽罩表面换热系数的影响。结果表明:锥尖区域，来流速度的影响与转速影响相比占主导；除锥尖外的其他区域，转速对换热系数的影响占据了主导地位；来流温度对整个表面的换热系数均有影响。采用不同工况下的数值模拟结果，在锥尖区域建立了来流雷诺数与努赛尔数之间的关联式；在除锥尖外的其他区域建立了旋转雷诺数与努赛尔数之间的关联式。

Abstract:

Heat transfer coefficient is an important parameter for icing and anti-icing of rotating cone. It needs to be known for computing heat transfer and evaporation in numerical simulation of ice accretion. In order to obtain this parameter，heat transfer coefficient on icing surface of a rotating cone has been simulated by numerical method. Firstly，grid independence and numerical approach were confirmed. Then，factors that affect heat transfer were analyzed，including revolving velocity，inflow velocity and inflow temperature. Heat transfer coefficients influenced by these factors on icing surface of a rotating cone with half angle of 40°and height of 176 mm were predicted. The results show that in the cone tip area inflow velocity is more important than revolving velocity，and in other area the revolving velocity is dominated，compared with inflow velocity，and the influence of inflow temperature is also apparent for all icing surface. Finally，heat transfer coefficient correlations are obtained on the base of numerical results under different conditions，in the tip area heat transfer coefficient correlated formula is established using Nu number and inflow Re number，and in other area the correlation is based on Nu number and involving Re number.