二次空气系统一维非定常计算方法

研究了燃气轮机二次空气系统的非定常计算方法.通过将整个二次空气系统划分为两部分,特征"长"元件以及局部损失元件.特征线法用于单个特征"长"元件的求解,通过将连续方程、动量方程、能量方程构成的偏微分方程组转换为常微分方程组并联立求解,可以充分考虑内部流动与换热的相互影响;基于压力修正的流体网络法则用于由多个局部损失元件组成的局部流体网络,首先对动量方程组进行求解,进而对各自的能量方程进行求解.如何在采用这两种方法进行求解的上述两类元件之间进行数据交互将被讨论.此外,所提出的时间步长定义方法以及改进的元件计算模型使得二次空气系统的非定常分析得以实现.计算程序经与某系统定常实验数据及单个元件的非定常计算数据进行对比,在10s的计算时间内,基于特征线法得到结果与CFD数据偏差达到10.2%,结果表明该计算程序可以满足二次空气系统非定常计算的要求.

One-dimensional unsteady calculational method of secondary air system

The unsteady calculational method of secondary air system in gas turbines was studied. The whole system was divided into several length correlated parts and discrete loss parts. The method of characteristic line was adopted for single length correlated parts, while partial differential equations of continuity, momentum and energy were transformed to ordinary differential equations under specified conditions, so the interaction of flow and heat transfer inside the parts itself could be taken into account. When the method of flow network based on pressure correction was used for discrete losses parts, momentum equations were solved prior to the calculation of respective energy equation. The process of data transfer on the interfaces between the mentioned two types of parts was discussed. With the method of time step definition and improved analytical models for different parts adopted, unsteady analysis of secondary air system was achieved. The program was validated against steady experimental data of the whole system and unsteady calculational data of individual parts; in 10s' calculational process, the result achieved by the program deviates 10.2% from that by CFD. The results indicate that the program can satisfy the need of unsteady calculation on secondary air system.