超燃冲压发动机冷却通道与燃烧室耦合传热数值研究

Numerical Study on Coupled Heat Transfer Between Cooling Channel and Combustor of Scramjet

关键词:  超燃冲压发动机  再生冷却  燃烧室  耦合换热  数值研究

Key words:  Scramjet  Regenerative cooling  Combustor  Coupled heat transfer  Numerical simulation

摘要:

为深入分析再生冷却通道与燃烧室的耦合传热过程以及探究多因素作用下的主动冷却耦合传热特性，采用航空煤油单组分替代模型，对超声速燃烧与流动裂解耦合换热过程进行数值模拟研究。探究了裂解反应、冷却流量、当量比对耦合传热的影响。结果表明：燃料的喷注与燃烧产生的扰动会破坏波系并向隔离段传递，燃烧强度随着燃烧的当量比增加变得更加剧烈；相同条件下，裂解产生的换热量在冷却流量较小时不可忽略，而冷却流量增加会使裂解程度减弱，当冷却流量为4g/s时正癸烷基本全部裂解，而增加至8g/s时裂解率不到10%；当量比对冷却通道与燃烧室的耦合传热的影响有限，当量比由0.67增加至0.84时，冷却通道出口温度升高约5K，燃烧室内壁温只增加了30K。

Abstract:

In order to further analyse the coupled heat transfer process of the regenerative cooling channel and the combustion chamber， and to explore the characteristics of coupled heat transfer in active cooling under multiple factors， a numerical simulation study of supersonic combustion and flow cracking coupled heat transfer processes was performed. The effects of cracking reaction， cooling mass flow and equivalent ratio on coupled heat transfer were analysed. The results show that the disturbance caused by fuel injection and combustion will destroy the wave system and transmit to the isolation section， and the combustion intensity becomes more intense as the combustion equivalent ratio increases. Under the same conditions， the heat transfer generated by cracking cannot be ignored when the cooling mass flow rate is small， and the increase of the cooling flow rate will shift the cracking position backward and the cracking degree will be weakened. When the cooling flow rate is 4g/s， the n-decane is completely cracked， and the cracking rate is less than 10% when it increases to 8g/s. Equivalent ratio has no significant effect on coupled heat transfer， when the equivalence ratio increases from 0.67 to 0.84， the cooling channel outlet temperature increases by about 5K， and the inner wall temperature in the combustion chamber increases by only 30K.