用于同轴喷射流引起的温度振荡数值模拟的湍流模型有效性研究

本文采用Fluent软件对同轴喷射流冷热流体搅混引起的三维温度振荡现象进行数值模拟。模拟中，分别选取几种代表性的湍流模型，如大涡模拟(LES)、雷诺应力模型(RSM)及标准k-ε模型。并将模拟结果与实验结果进行了对比，发现：LES是最适合预测冷热流体搅混特性的模型；LES可准确预测温度振荡在半径、高度和方位角方向的平均温度，而雷诺平均法(RANS)的结果则延长了流体的混合过程；LES可预测流体的瞬态温度振荡，RANS则无法预测。

Research on Effect of Turbulence Models for Numerical Simulation of Temperature Fluctuation Caused by Coaxial-Jet Flow

The 3D temperature fluctuation phenomenon caused by the mixing of the coaxial-jet hot and cold fluids was simulated by Fluent software.Several special turbulence models were applied to prediction of this phenomenon,i.e.large eddy simulation model(LES),Reynolds stress model(RSM) and standard k-ε model.By the comparison of the computed data and experimental ones,it is shown that LES is capable of predicting the mixing process.LES model best predicts the time-averaged temperature in the radius,height and azimuth directions.Reynolds averaged Navier-Stokes method(RANS) predicts the extended mixing of the hot and cold fluids.It is also shown that the transient temperature fluctuations are accurately predicted by LES model,while those not by RANS.