循环水泵流道研究与应用

Research and application on flow channel of circulation pump

由于安装位置的限制,某电厂循环水泵房和机力通风塔的水平距离仅十余米,纵向落差达4.6 m,采用2次转弯达90°的暗涵流道来连接机力塔水池和吸水室,导致吸水前池进流条件较为恶劣,其对循环水泵的运行效率和安全影响十分突出。为解决这一问题,进行了水工模型试验。结果表明,在吸水室前部布置足够深度的胸墙后,能够有效消除上游弯道进流引起的环流,水流经胸墙调整后变得均匀稳定,而胸墙布置深度是优化吸水室流态的关键参数,为此进行了多方案试验,选择出最佳胸墙布置深度,使循环水泵吸水管管内涡角平均值降至零左右,基本消除喇叭口附近及吸管内水流的旋转流动,吸管喇叭口进流稳定,流速分布更为均匀,能较好满足水泵高效、稳定的运行要求。此外,还对事故停泵工况进行了研究,给出2种循环水泵吸水室排气的设计方案。将试验所得优选方案运用于工程实践,效果良好。

Due to the restrictions on the installation location,the horizontal distance of a circulation water pump station and mechanical draft towers was only ten meters,and the vertical drop was 4.6 m.Using the culvert channel with two 900 turning angle to connect the machine power tower and an absorbent chamber,the conditions of water flow inlet for previous pool of absorbing water was relatively poor.So the efficiency and safety of circulation pump decreased greatly.In order to solve this problem,the hydraulic model test was carried on.The results show that the sufficient depth of parapet in the front of suction chamber can effectively eliminate the circulation flow caused by inlet flow of upstream bend.After adjustment the water flow becomes uniform and stable,and the layout depth is the key parameter to optimize the water flow state of absorbing water chamber.By lots of tests the best choice of parapet layout depth,zero mean value of vortex angle in the circulation pump absorption water tube,elimination of rotating flow in trumpet and near the straw,the stability of inlet flow in straw trumpet,and the uniform distribution of flow velocity were gained,which can satisfy the requirements of high efficiency and stable operation of water pump.In addition,the pump accident condition was researched,and two kinds of exhaust designs for suction water chamber in circulation pump were proposed.The engineering applications of the optimization scheme achieve good effects.