YING Qiyu, ZHUGE Weilin, ZHANG Yangjun, et al. Aerodynamic design and numerical analysis of a multi-stage axial supercritical carbon dioxide turbine[J]. Thermal power generation, 2020, 49(10): 164-172. DOI: 10.19666/j.rlfd.202004180.
多级轴流超临界二氧化碳透平气动设计及仿真分析
摘要
透平是超临界二氧化碳(S-CO_2)布雷顿循环系统的核心部件
目前主要面临效率低的问题。本文针对1台4级轴流S-CO_2透平进行气动设计
并对透平内部流动进行了三维数值模拟分析。结果表明
动叶叶顶间隙泄漏流是影响透平流动和性能的主要因素
泄漏流不仅会与叶片通道主流相互作用
还会影响下一级静叶流动
在入口产生较大攻角
引起静叶叶顶吸力面前缘和压力面喉口部的流动分离
并影响下游动叶叶顶端流动
导致泄漏流强度随级数累积增强
降低透平效率。根据流动仿真分析结果对透平进行了改进设计
使透平效率显著提高
达到84.44%。
Abstract
Turbine is the core component in supercritical carbon dioxide(S-CO_2) Brayton cycle
while low efficiency is a major problem in current S-CO_2 turbine research. This paper provides an aerodynamic design for a four-stage S-CO_2 axial turbine. Three dimensional numerical simulation of the designed turbine is carried out and the turbine internal flow field is analyzed. The results show that
the rotor tip leakage flow is the primary factor that affects the turbine internal flow and performance. The tip leakage flow not only interacts with main flow
but also influences the stator inlet flow in the following stage. High inlet incident angle could be seen at the stator tip
which leads to the flow separation at both stator blade surfaces. This flow separation affects following rotor flow further. As a result
a secondary vortex is developed and turbine efficiency is lowered. On this basis
an improved turbine design is proposed correspondingly and the turbine efficiency is increased to 84.44%.