汽轮机低压排汽缸气动性能的数值研究

摘要

Based on the effects of aerodynamic performance of low-pressure exhaust hood on the steam tur- bine efficiency, numerical simulations were carried out on a small-scale test model of low-pressure exhaust hood to obtain the wall pressure distribution of guide ring at diffuser inlet and the velocity distribution of characteristic plane at diffuser outlet, during which the calculated results were compared and verified with actual measurements. Moreover the performance of diffuser and volute was analyzed by numerical simula- tion method. Results show that the vortex structure is very complicated between the diffuser and volute, and the passage vortex is found to be the main cause leading to the reduced diffusion capacity and energy loss in the exhaust hood.%针对汽轮机低压排汽缸气动性能对汽轮机组效率的影响，采用小尺寸试验模型对汽轮机低压排汽缸进行了数值模拟，得到扩压器进口导流环壁面压力分布和出口特征平面速度分布，并与相应的试验测量结果进行了比较，验证了数值计算结果的可靠性．通过数值模拟方法分析了扩压器和蜗壳的性能．结果表明：汽轮机扩压器导流环和蜗壳之间的涡系结构复杂，通道涡是造成排汽缸扩压能力降低和能量损失的主要因素．