110kN核热发动机推力室非平衡流动传热数值模拟研究

CFD Simulation of Non-equilibrium Flow and Heat Transfer in Thrust Chamber of a 110 kN Nuclear Heat Engine

为预测110 kN核热发动机堆芯外推力室流动传热情况,建立了推力室身部和喷管延长段三维一体模型,采用数值模拟方法对堆芯出口至喷管出口间的高温氢气、推力室壁和超临界氢的流动传热进行了耦合计算。考虑再生冷却通道内超临界氢的物性变化,采用SST k-ω模型计算了整个湍流场,有限速率反应模型计算氢的非平衡离解,比较了进入喷管的氢气在无离解态、平衡离解冻结态和非平衡离解态下的流动传热特性,并讨论了中子热沉积对再生冷却传热的影响。结果表明:氢的非平衡离解反应对发动机比冲影响显著,而对推力室再生冷却传热影响较小;与无离解反应流和平衡离解冻结流相比,氢气非平衡离解作用下发动机比冲和再生冷却温升均增大;中子热沉积对再生冷却传热影响很小。

To accurately predict the flow and heat transfer in thrust chamber outside the core of a 110 kN nuclear thermal rocket engine,an integrated three-dimensional model of the thrust chamber body and the nozzle extension was established,and the numerical simulation was used to calculate the coupled heat transfer of high-temperature hydrogen,thrust chamber walls,and supercritical hydrogen from the core exit to the nozzle exit.Considering the changes of physical properties of supercritical hydrogen in regenerative cooling channel,the SST k-ωturbulence model was used to calculate the turbulence flow field,and the finite rate reaction model was used to calculate the non-equilibrium dissociation of hydrogen.The flow and heat transfer characteristics of hydrogen entering the nozzle in the non-dissociated state,equilibrium dissociated frozen state,and non-equilibrium dissociated state were compared.In addition,the effects of neutron deposition on regenerative cooling and heat transfer was discussed.The results showed that the non-equilibrium dissociation of hydrogen had a significant effect on the performance of rocket engine,but had little effect on regenerative cooling and heat transfer.Compared with the non-dissociated reaction flow and equilibrium frozen flow,both the specific impulse and the regenerative temperature rise increased under the hydrogen non-equilibrium dissociation.Moreover,the neutron thermal deposition had little effect on the regenerative cooling and heat transfer.