汽轮机DEH系统转子温度场算法的分析研究

Analytical Research on Rotator Temperature Field Algorithm for Turbine DEH Systems

根据能量平衡原理,推导了计算汽轮机转子温度分布的4点显式等分网格的有限差分法,分别采用4点显式等分网格的有限差分法、6点隐式等分网格的有限差分法和有限元法对1 000MW汽轮机高压转子的冷态启动过程进行了温度场的计算分析。结果显示:4点显式等分网格的有限差分法和6点隐式等分网格的有限差分法的计算精度相同,与有限元法也相差不大,应用于汽轮机转子热应力监控有足够的精度;4点显式等分网格的有限差分法对计算时间步长的要求较严格,推导出了避免计算发散的条件。

According to the principle of energy balance, a four-point explicit equal grid finite difference method was deduced for calculating the temperature distribution of turbine rotators. A temperature filed computational analysis was carried out for cold-start process of a 1 000 MW high pressure turbine rotator respectively by the four-point explicit equal grid finite difference method, six-point implicit equal grid finite difference method, and the finite element method. Results show that the four-point explicit equal grid finite difference method and six-point implicit equal grid finite difference method have nearly the same calculation precision, which differs little from that of the finite element method, and the calculation precision is high enough for thermal stress monitoring of turbine rotators; the four-point explicit equal grid finite difference method has strict requirements on the calculation time step. Moreover, the conditions for avoiding computation divergence are deduced simultaneously.