塞式喷管结构对固液火箭发动机的性能影响 *

Effects of Aerospike Nozzle Structure on Hybrid Rocket Motor Performance

关键词:  塞式喷管  固液火箭发动机  数值仿真  性能

Key words:  Aerospike nozzle  Hybrid rocket motor  Simulation  Performance

摘要:

为了分析塞式喷管结构对固液火箭发动机的性能影响，分别设计了使用塞式喷管和钟形喷管的固液火箭发动机。发动机喷管选取了三个不同的扩张比，对应高空和地面两个设计状态。通过数值仿真，预估了发动机的性能，并将使用塞式喷管结构和钟形喷管结构的两种固液火箭发动机进行了对比分析。结果表明:相对于钟形喷管结构，使用塞式喷管结构能够提高固液火箭发动机的燃烧效率和比冲效率，且最大分别提高了4.13% 和3.37%；地面条件下，大扩张比的塞式喷管的仿真推力系数要比同扩张比的钟形喷管的仿真推力系数大2.69%，体现出塞式喷管的高度补偿效应；与钟形喷管内壁面温度相比，塞式喷管塞锥壁面的温度明显更低。

Abstract:

In order to analyze the effects of an aerospike nozzle structure on the performance of hybrid rocket motor， aerospike nozzle and bell nozzle were designed respectively. Three different expansion ratios of motor nozzles were selected， corresponding to design conditions of high altitude and ground. The performance of the motors was evaluated with numerical simulation method. Hybrid rocket motors with aerospike nozzle structures were compared with those with bell nozzle structures. The results show that the combustion efficiency and the specific impulse efficiency of hybrid rocket motors with aerospike nozzle structures are respectively 4.13% and 3.37% higher than those with bell nozzle structures at most. Under the condition of ground， the simulated thrust coefficient of aerospike nozzles with a large expansion ratio is 2.69% larger than that of bell nozzles with the same expansion ratio， which reflects the altitude compensation effects of aerospike nozzle. Compared with the temperature of bell nozzle inner wall， the temperature of aerospike nozzle plug wall is significantly lower.