液体火箭发动机尾焰复燃对红外辐射特性的影响

Effects of Afterburning on Infrared Radiation Characteristics of Liquid Rocket Exhaust Plume

关键词:  液体火箭发动机  尾焰  复燃反应  有限速率化学反应  红外辐射特性

Key words:  Liquid rocket  Exhaust plume  Afterburning  Finite rate chemistry reaction  Infrared radiation characteristics

摘要:

为深入研究液体火箭发动机尾焰复燃对红外辐射特性的影响，建立了一个适用于液体火箭尾焰复燃流场和红外辐射特性的计算模型。利用FLUENT软件计算液体火箭尾焰复燃流场，其中复燃反应采用有限速率化学反应模型；采用HITEMP数据库利用逐线积分法(LBL)计算尾焰气体的辐射气体参量；采用反向蒙特卡洛法(BMC)求解辐射传输方程，得到尾焰复燃流场的红外辐射特性。结果表明，复燃反应可大幅度改变尾焰流场特性，进而改变尾焰红外辐射特性。相比于冻结流，反应流流场温度和主要辐射气体含量最大增幅分别可达15.4%及47.5%，主要辐射波段内辐射强度最大增幅可达31.5%。随发动机飞行高度增加，复燃反应所引起的红外辐射强度增量随之降低。

Abstract:

In order to research the effects of afterburning on infrared radiation characteristics of liquid rocket exhaust plume， a simulation model was founded which was able to calculate afterburning plume field and infrared radiation characteristics of exhaust plume. Firstly， liquid rocket plume field was simulated by FLUENT， in which the afterburning reaction was controlled by finite rate chemistry reaction. Secondly， line by line integral method (LBL) was used to calculate the parameters of plume gas， based on HITEMP data. Finally， the radiation transfer equation was solved by Back Monte Carlo method (BMC) to acquire the infrared radiation characteristics of afterburning exhaust plume. The results indicate that afterburning can increase the infrared radiation intensity of exhaust plume greatly by changing the characteristics of plume filed. The temperature and radiation gas mole fraction of reaction plume are respectively 15.4% and 47.5% higher than those of frozen plume. In the main radiation range， the radiation intensity increased by 31.5%. With the flight height increasing， the increment of infrared radiation caused by afterburning decreases.