高焓电弧风洞试验热化学非平衡流场数值模拟

针对高焓电弧风洞内部流动的热化学非平衡效应及气体组分和振动能量冻结效应导致的试验数据外推困难问题，基于高焓风洞喷管/试验段/试验模型一体化数值模拟的思路，通过数值求解三维热化学非平衡Navier-Stokes方程，开展了FD-15高焓电弧风洞典型运行状态下流场的数值模拟，与典型试验状态的气动热数据进行了对比验证，研究了试验数据外推飞行条件的方法及有效性问题，分析了提高驻室总压对试验数据外推的影响。研究表明:（1）风洞试验段来流离解度高，热化学非平衡效应及其冻结现象严重；（2）热流校核试验测量数据位于一体化数值模拟的完全催化热流和非催化热流之间，分布合理，验证了计算方法和程序的正确性；（3）试验模型安放位置对模型表面压力和热流存在影响，模型与喷管出口的距离越大，模型表面压力和热流越低；（4）当驻室总压较低时，通过双尺度模拟准则（模拟飞行条件总焓和双尺度参数ρ_∞L）外推热流失效，使用部分模拟准则（模拟飞行条件总焓和驻点压力）外推热流也会出现较大差异，在非催化条件下这一现象更加明显；（5）当驻室总压较高时，使用双尺度模拟准则或部分模拟准则外推飞行条件，产生的热流差异明显减小。

Numerical simulation of thermochemical non-equilibrium flow field in arc-jet tunnel

Due to the thermochemical non-equilibrium effects and the freezing of species mass fractions and vibration energy, it is difficult to determine the flight conditions based on the arc-jet tunnel test data by extrapolation. In consideration of this problem and based on the idea of the integrated numerical simulation of the nozzle/test section/test model flow field, the numerical simulation of FD-15 arc-jet tunnel test under the typical operating condition is conducted by solving three dimensional Navier-Stokes equations of the thermochemical non-equilibrium flow. Based on the simulation result, the comparison between the numerical simulation and the tunnel test result is presented, and the problem of extrapolating the tunnel test data to flight as well as the influence of the reservoir pressure on extrapolation are discussed. The result shows:(1) the inflow in the test section has a high level of dissociation, and thus the thermochemical non-equilibrium effect is severe. (2) The tunnel test heat flux result is in between the full catalytic heat flux and non-catalytic heat flux of the integrated numerical simulation, which is reasonable and indicates the validity of the computation method and program. (3)The surface pressure and the heat transfer can be influenced by the installation position of the test model. The surface pressure and the heat transfer flux decrease when the distance from the test model to the nozzle exit increases. (4)When the reservoir pressure is low, extrapolation of the tunnel test heat flux data to the flight conditions by binary scaling (keeping total enthalpy and ρ_∞L the same) is invalid, and the tunnel test heat flux data also shows discrepancies in extrapolation to flight conditions by partial simulation (keeping total enthalpy and stagnation pressure the same), especially under non-catalytic condition. (5)When the reservoir pressure increases, discrepancies in extrapolation of the tunnel test data are significantly reduced with both binary scaling and partial simulation methods.