单孔冲击式帽罩前缘流动换热特性数值分析

为了提高航空发动机帽罩冲击防冰结构的设计分析水平,对单孔冲击式帽罩前缘结构的流动换热特性进行数值研究,分析了不同冲击孔径与不同冲击雷诺数对帽罩前缘速度流场、换热系数与努塞尔数的分布规律。结果表明:在冲击雷诺数一定的条件下,冲击孔径越大,射流核心速度和前缘壁面附近的气流速度越小,前缘冲击区形成的涡流团越大,当孔径D=6 mm时,小孔径冲击下前缘区整体换热效果不如大孔径的,而在滞止区的换热效果则要优于大孔径的;当D>12 mm时,孔径大小对壁面换热基本没有影响;在冲击孔径相同时,增大冲击雷诺数使得冲击射流、前缘壁面附近及侧壁曲面通道内的气流流速增大,冲击区内的涡流团则逐渐减小;冲击雷诺数的增大也增强了前缘冲击区的换热特性。

Numerical Analysis of Flow Heat Transfer Characteristics of Leading Edge of Single-hole Impact Cone

In order to improve the design and analysis level of the impact ice proof structure of the aeroengine cone,the flow heat transfer characteristics of the leading edge structure of the single-hole impact cone were studied by numerical method.The distribution of velocity flow field,heat transfer coefficient and Nussel number at the leading edge of cone was analyzed with different impingement aperture and different impingement Reynolds number.The results show that under the condition of a certain impingement Reynolds number,the larger the impingement aperture is,the smaller the core velocity of the jet and the velocity of the airflow near the leading edge wall are,and the larger the vortex mass formed in the front edge impact zone.When the aperture D=6 mm,the overall heat transfer effect at the leading edge under small impingement aperture is not as good as that in large impingement aperture,while the heat transfer effect in stagnation region is better than that in large impingement aperture.When the aperture is larger than 12 mm,the aperture size has no effect on heat transfer.When the impingement aperture is the same,with the increase of impingement Reynolds number,the airflow velocity near the leading edge wall and in the curved channel of the side wall increases,and the vortex mass in the impact area decreases gradually.The increase of impingement Reynolds number also enhances the heat transfer characteristics of the leading edge impact zone.