叶轮外径对前弯型液力透平性能的影响

发布时间：2018-01-01 14:04

本文关键词：叶轮外径对前弯型液力透平性能的影响　出处：《机械工程学报》2016年22期 　论文类型：期刊论文

【摘要】：为研究前弯型叶轮外径对液力透平水力性能的影响,进行试验,获得了液力透平外特性数据,与计算流体动力学(Computational fluid dynamics,CFD)的结果进行对比分析,发现两者结果十分接近,验证了CFD模拟的准确性。利用CFD技术获得了215 mm、235 mm和255 mm叶轮外径液力透平的外特性曲线,发现随叶轮外径的增加,高效点向大流量区域偏移,在大流量区域,扬程大幅下降,轴功率小幅提升,效率有较明显提升,在小流量区域,扬程上升,轴功率略微下降,效率下降明显。对215 mm、235 mm和255 mm外径叶轮的速度场分析,发现随叶轮外径的增加,叶轮与蜗壳基圆之间的循环流量逐渐减小,流动状态得到明显改善,叶轮内水力损失也有较为明显的减小。利用理论公式推测改变了叶轮外径后的液力透平的高效点参数,发现普遍高于CFD模拟结果,分析产生差值的可能原因。对液力透平的轴功率、扬程进行理论分析,探讨其随叶轮外径增加的变化趋势。
[Abstract]:In order to study the influence of the outer diameter of the forward curved impeller on the hydraulic performance of the hydraulic turbine, the external characteristic data of the hydraulic turbine were obtained. Comparing with the results of Computational fluid Dynamics (CFD) and Computational fluid dynamic (CFDs), it is found that the two results are very close to each other. The veracity of CFD simulation is verified. The external characteristic curves of outer diameter hydraulic turbine of 215mm / 235mm and 255mm impeller are obtained by CFD technique, and it is found that the outer diameter of impeller increases with the increase of the outer diameter of impeller. The high efficiency point shifts to the large flow area, in the large flow area, the head greatly drops, the shaft power increases slightly, the efficiency has obvious enhancement, in the small flow area, the lift rises, the axis power drops slightly. The analysis of the velocity field of 215mm / 235mm and 255mm outer diameter impellers shows that the circulation flow between the impeller and the base circle of the volute decreases with the increase of the outer diameter of the impeller. The flow state is obviously improved and the hydraulic loss in the impeller is obviously reduced. The high efficiency point parameters of the turbine after changing the outer diameter of the impeller are estimated by using the theoretical formula. It is found that it is generally higher than the result of CFD simulation. The possible causes of the difference are analyzed. The shaft power and the head of the hydraulic turbine are analyzed theoretically, and the variation trend with the increase of the outer diameter of the impeller is discussed.
【作者单位】：江苏大学国家水泵及系统工程技术研究中心;
【基金】：江苏省青年科学基金资助项目(BK20130517)
【分类号】：TK05
【正文快照】： 0前言1 随着社会经济的高速发展,我国能源需求急速增加,建造小型水电站可以减轻愈发严重的能源危机[1]。液力透平具有价格便宜、安装方便、更换易损件容易和维护成本低等优点,因而较为广泛地应用在小水电站中[2]。国外学者起步较早,PUNIT等[3]主要采用试验的方式,在现有

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