考虑低温增压真实气体效应的运输机气动特性数值模拟研究

为了给低温风洞试验数据修正提供参考，本文利用数值模拟手段研究了低温真实气体效应相比较于完全气体对飞行器气动特性的影响，以及该影响与雷诺数影响相比所占比例的大小等问题。文章应用 Aungier-Redlich-Kwongz 方程，发展了适用于模拟氮气低温高压真实气体效应的 RANS 求解软件。与 NIST 数据的对比表明，该状态方程在5倍大气压下，比热比等参数误差在0.3%以下。同时，标模测试结果表明本文软件计算精度与国外软件相当。应用本文方法研究低温增压风洞中氮气真实气体效应：以典型运输机构型 DLRF6为模型，分别计算了高速、低速状态下各种不同温度和压力工况下的流动。计算结果表明，在低温增压情况下，真实气体效应引起的气动力差异很小，升力、阻力、力矩最大相对误差均在0.3%以下，与雷诺数效应引起的偏差相比可以忽略不计。因此，以氮气为介质的低温风洞试验研究可以采用完全气体假设。

Numerical simulation of transport aircraft under low temperature and high pressure real gas effect in wind tunnel

To provide reference for data correction of the cryogenic wind tunnel, the vechicle′s aerodynamic character is researched with numerical method.In the research,the real gas effect on vehicle is studied through the comparison between real low temperature gas and perfect gas,and the ratio of real gas effect to Reynolds number effect is also studied.Employing Aungier-Redlich-Kwongz equation,a new RANS code is developed,to research the real gas effect of nitrogen in cryogenic and high-pressure condition.Comparing with NIST data,Aungier-Redlich-Kwongz equation maintains the deviation of specific heat below 0.3% under 5 times atm pressure.Also,standard model test indicates that the current code is comparable to international softwares.Researches are taking on the real gas effect of nitrogen in cryogenic wind tunnel with the current code.The typical transport aircraft of DLRF6 is selected as the calculation model, and its surrounding flowfields are obtained in different conditions, such as different inflow speeds,temperatures and pressures.The calculation results show that,in the low temperature and enhanced pressure condition,the variation from the real gas effect is rather low,and the relative deviations of lift,drag and moment are all below 0.3%,which are neglectable to the effect of Renolds number.Thus,the medium of nitrogen in cryogenic wind tunnel can be assumed to be perfect gas in the experiment analysis.