300MW汽轮机凝汽器喉部出口流场的三维数值模拟  

Three-dimensional Numerical Simulation of the Outlet Flow Field of the 300 MW Steam Turbine's Condenser Throat

作　　者：曹丽华[1] 郭婷婷[1] 李勇[1] 

机构地区：[1]东北电力大学,吉林省吉林市132012

出　　处：《中国电机工程学报》2006年第11期56-59,共4页Proceedings of the CSEE

基　　金：东北电力学院科研基金项目（DDYKY200502）资助.

摘　　要：为了减少占地面积,国产优化引进型300MW汽轮机将压力最低的2个低压加热器放置于凝汽器喉部,从而导致汽轮机喉部流场出现不均匀,最终导致凝汽器热负荷的不均匀。文中采用κ-ε模型并结合壁面函数法,利用SIMPLEC 算法编程,对300 MW汽轮机喉部流场进行了三维数值模拟,分析了凝汽器喉部出口流场的不均匀性和造成流场不均匀的原因。结果表明,由于内置式低压加热器的影响和凝汽器喉部棱台扩散的作用,使凝汽器喉部出口流场的速度分布产生很大的不均匀性。汽流在低压加热器两侧形成局部的高速区,并延续到喉部出口截面。同时,在低压加热器的正下方形成低速涡流区,在喉部斜壁下方也产生一定的回流,并且在靠近凝汽器入口截面的4个角处形成低速区。对该凝汽器喉部流场的三维数值模拟结果,有助于了解具有内置式低压加热器凝汽器喉部汽流的流动机理,为凝汽器喉部的设计和改造以及汽轮机的经济运行奠定一定的基础。In order to reduce the occupied area, the two lowest pressure heaters are laid in the condenser throat to the optimizing introducing 300MW steam turbine made in China. But this disposal causes the non-uniformity of the steam turbine throat flow field, finally causes the non-uniformity of the condenser heat load. In this paper, using the k-e model, the wall-function method and the SIMPLEC algorithm method, the three-dimensional numerical simfllation of the flow field in the 300MW steam turbine throat is done. The non-uniformity of the flow field at the condenser throat outlet and its reason are analyzed. The result indicated that the velocity distribution of the flow field at the throat outlet has the great non-uniformity because of the influence of the inner low-pressure heater and the diffuse function of the condenser throat＇s prism structure. The partial high-speed steam flow area is formed in the low-pressure heater two sides, and extended to the throat outlet. At the same time, the low speed eddy zone is formed underneath the low-pressure heater, also the certain backflow is formed under the throat slanting wall, and the low speed area is formed at the four angles place approaching the condenser inlet. The three-dimensional numerical simulation of the flow field result of this type condenser is helpful to understanding exhaust steam flow mechanism of condenser throat with inner low- pressure heater. And this conclusion lays the certain foundation for the design, the transformation of the condenser throat, and the economical operation of the condenser.

关 键 词：热能动力工程 凝汽器喉部 流场 数值模拟 

分 类 号：TK26[动力工程及工程热物理—动力机械及工程]