脉冲射流强化喷流混合的数值模拟

采用高振幅低流量射流射入亚音剪切层以强化喷流混合,对利用脉冲射流强化喷流混合的流场进行了数值模拟.利用有限体积法和重整化群(RNG)k-ε湍流模型求解N-S方程.分别进行了低亚音马赫数及中等亚音马赫数喷流混合的数值模拟.数值模拟结果显示,无论是对于低亚音速热喷流还是中等亚音速热喷流,脉冲激励引起喷流在与激励源平行的平面迅速扩展,在与之垂直的平面收缩,当脉冲射流激励的斯德鲁哈尔数在0.2时,可以得到较好混合,而且少量的射流流量(占主流流量的1%)可以极大地增加速度及温度的衰减率,随着流量的增加(占主流流量的3%),喷流混合得到进一步的加强.

Jet mixing enhancement by pulsed blowing

This work uses a technique for injecting high amplitude and low mass flux pulsed slot jets into subsonic shear layers for the purpose of jet mixing enhancement.The 3-D flow fields of the jets with pulsed jet blowing for mixing enhancement were simulated numerically.The finite volume method,RNG κ-ε turbulence model were employed to solve N-S equation.Numerical simulations of low Mach number 0.2 and middle Mach number 0.6 jets exhausting into fluid were conducted.These simulations show that pulsed jet blowing effected on either low Mach number jets or middle Mach number jets causes the jet to expand rapidly in the plane par-allel with the actuators and to contract in the plane perpendicular to the actuators,the intensity of motion and associated mixing are higher when the excitation Strouhal number is around 0.2,and small injection flow rates can provide tremendous increases in both velocity and temperature decay rates.With the increase of the pulsed slot jet mass flux,a better mixing can be obtained.