烧蚀热防护材料在高热负荷下会发生热解，产生的热解气体进入到边界层中会起到降热减阻效应。首先建立壁面质量引射边界条件，验证该边界的准确性，并针对高超声速钝楔模型，研究了不同攻角，不同引射气体对壁面热流和摩擦阻力的影响机理和规律。计算结果表明，由于壁面质量引射的存在，迎风面激波脱体距离增加，高温区域远离壁面，壁面热流和摩擦阻力均降低。同时相比于空气引射，同等质量流率下热解气体引射导致的激波脱体距离更远，壁面附近的温度梯度、粘性系数和切向速度梯度也减小更多，因此降热减阻效果也更为显著，并且随着攻角的减小，迎风面质量引射的降热减阻效率有所增大。此外，引射质量流率的增加提高了降热减阻效率，空气引射的质量流率为热解气体的两倍时，两者的降热减阻效率才近乎相等。

The ablative thermal protection material will be pyrolyzed under the high thermal load. The pyrolysis gas is injected into the boundary layer, reducing the heat flux and skin-friction drastically. Firstly, we establish the boundary condition of wall mass injection and verify the accuracy of this boundary. After that, for the hypersonic blunt wedge model, we study the mechanism of the influence of different angles of attack and different gases on the heat flux and skin-friction. The nu-merical results show that due to the wall mass injection, the distance of the windward detached shock between the wall increases, and the high-temperature region is pushed away from the wall, reducing the wall heat flux and skin-friction. Compared with air injection, the detached shock distance due to pyrolysis gas at the same mass flow rate is farther, and the temperature gradient, viscosity coefficient, and velocity gradient also reduce obviously in the boundary layer. There-fore, the reduction of heat flux and skin-friction by pyrolysis gas injection is more significant. In addition, with the de-crease of attack angle, the heat flux and skin-friction reduction efficiencies increase. Comparing the results at different mass flow rates, it is found that the increase in air injection mass flow rate improves the efficiencies of heat reduction and drag reduction, and the efficiencies of both was nearly equal when the air injection mass flow rate is twice that of the py-rolysis gas.