考虑湿蒸汽热力行为的汽轮机排汽通道加装导流装置的研究

摘要

针对汽轮机排汽通道的复杂三维流动造成凝汽器喉部出口流场的不均匀现象，采用湿蒸汽模型，对排汽通道加装导流装置前后的流场进行三维数值模拟。结果表明：小汽轮机排汽侧的低速区、靠近中心区域的漩涡低速区、壁角处的高速区及蒸汽湿度的变化是影响凝汽器喉部出口截面速度分布不均匀的主要因素。通过数值试验，加装导流装置后，在不同进口湿度工况下，能量损失系数增加了约5％而均匀性系数增加了约12％。所得出的导流装置加装方案能够在引起较小的能量损失情况下，有效改善排汽通道流场的均匀性。%Aimed at the non-uniform phenomenon of the outlet flow field in condenser throat,which caused by complex 3-D flow in steam turbine exhaust passage, the flow field of exhaust passage, before and after the installation of flow guide devices,were 3-D numerically simulated using the wet steam model.The results show that the main factors,affecting the non-uniform velocity distribution of the outlet flow field in condenser throat,include the low velocity range of boiler feed pump turbine side,the low velocity vortex range nearing to center area,the high velocity range of wall corner and the change of wet steam humidity.Through a serial of numerical experiments,at the different humidity of wet steam,the uniformity coefficient and the energy loss coefficient increased by about 5%and 12%,respectively,after the installation of flow guide devices.This installation scheme of flow guide devices can cause the smaller energy loss and improve effectively the flow field uniformity in exhaust passage.