过渡态工况下环形燃烧室热态三维数值模拟

Numerical simulation of three-dimension combustion in an annular combustor during a transient state

利用商用软件对环形燃烧室从慢车到最大状态的过渡态过程进行了数值模拟,并通过与传统的工程计算方法(利用稳态计算来近似过渡态计算)得到的结果进行分析比较,研究了过渡态过程对燃烧室温度场的影响,结果表明:①过渡态计算与对应工况点的单点稳态计算存在一定的差别,主要表现在稳态计算的出口温度比过渡态计算的整体偏高;②时间步长是影响过渡态计算的关键因素,较小的时间步长能够使不同时刻流场参数之间的相互联系更加紧密,计算结果也就更接近于过渡态的真实过程;③过渡态计算中出口平均温度相对于油气比的变化在时间上具有一定的滞后性.

A numerical investigation of an annular combustor in a transient state （from idle to maximum） was conducted with commercial software FLUENT by adding the UDF （user-defined function） subroutines. Temperature field was studied by comparing with traditional method （which used steady simulation at some discrete operation conditions to approximate the transient state）. The results show that： （1）there are large differences between transient and steady simulation at corresponding operation condition; the outlet temperature distribution of steady simulation is higher than the transient simulation; （2） the time step is a critical factor affecting the accuracy of transient simulation; a small time step could account for the close interaction with flow filed parameters of different times; （3） a hysteresis phenomenon during the transient state exists at the averaged outlet temperature in relation to fuel-air ratio.