液体火箭发动机燃烧室燃烧效率计算理论

本文提出了一个高压液体双组元自燃推进剂火箭发动机燃烧室计算模型。利用此模型对特种发动机燃烧室不同工况进行了计算,所得结果和各参数变化规律与试验数据相符合。该模型能将燃烧历程与燃烧室结构参数、工作参数、推进剂特性等关联起来,因而可为燃烧室设计提供理论予测。 

A THEORY OF COMBUSTION EFFICIENCY COMPUTATION FOR LIQUID ROCKET ENGINE COMBUSTOR

A mathematical model describing combustion in a high pressure liquid hyper-golic bipropellant(UDMH/H2O4) rocket engine combustor has been developed. In this model, the droplet evaporation process at high ambient pressure has been considered,which takes into account the droplet surface regression, the transient heating, the effects of ambient pressure on vapor-liquid equilibrium, the effects of nonideal gas behaviour, the dissociation of N2O4 and the decomposition of UDMH. The gas temperature variation has also been considered which is dependent on the local mixture ratio, the drop-size distributions and the effects of the convergent section of nozzle on the vaporization rates.Since the mechanism of the droplet secondary breakup process is different under a large flow flux,a new secondary breakup critical condition is proposed.The application of this mathematical model to different operating conditions of a specific rocket combustor is provided. The calculated results are in good agreement with experimental data. This model correlates the combustion process with the engine structure parameters, the operating parameters and the properties of the propellant. Therefore, it may be used as a guideline and a theoretical prediction for designing rocket engine combustor.