基于流体体积模型的叶片数对水车性能的影响  

Effects of number of blades on performance of waterwheel based on volume of fluid model

作　　者：赵梦晌 郑源[2] 杨春霞[2] 臧伟 ZHAO Mengshang;ZHENG Yuan;YANG Chunxia;ZANG Wei(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing,Jiangsu 210098,China;College of Energy and Electrical Engineering,Hohai University,Nanjing,Jiangsu 211100,China)

机构地区：[1]河海大学水利水电学院,江苏南京210098 [2]河海大学能源与电气学院,江苏南京211100

出　　处：《排灌机械工程学报》2020年第7期677-682,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金青年基金资助项目(51709086)。

摘　　要：为了研究一种利用微水头发电的水车装置,利用Fluent软件流体体积(VOF)模型模拟明渠无压流动,选用SST k-ω两方程湍流模型和滑移网格旋转模型对不同叶片数的水车在不同转速下进行非定常模拟.结果表明:3叶片水车效率区最为宽广,最优效率最高;3叶片水车上游局部湍流黏度较大,影响范围较小,而8叶片水车上、下游湍流黏度较为平均,影响范围较大;相同工况下,增加叶片数会增强水车的阻塞效应,使上、下游水位差平均增大,但可降低水位差的波动,水位差平均值增大将降低水车出力,水位差的波动对水车轴系的稳定性产生不利的影响;相同工况下,增加叶片数可以提高水车运行中转矩波动的稳定性,但会降低水车的出力,转矩波动使水车在运行中受到周期性不平衡力矩的作用,引起水车结构剧烈振动和叶片疲劳损伤.Unsteady flow around waterwheels in an open channel was simulated numerically in Fluent based on volume of fluid(VOF)model to study the waterwheel-based power generation device by utilizing micro-head.The SST k-ωtwo-equation turbulence model and sliding mesh were adopted to carry out unsteady flow simulations when the waterwheels ran with different numbers of blades and at different rotational speeds.The results indicate that the 3-bladed waterwheel has the best optimal efficiency and the widest optimal efficiency zone.Since the local turbulent viscosity in the upstream of the 3-bladed waterwheel is larger,the range of influence generated by the waterwheel in the channel is smaller.For the 8-bladed waterwheel,however,the average turbulent viscosity in the upstream is fair,the range of the influence is larger.Under the same working condition,adding more blades can intensify the waterwheel blockage effect to the stream and elevate the average water level difference between upstream and downstream significantly,but suppress the fluctuation of water level difference.An increased average water level difference will reduce the waterwheel power output,and the fluctuation of water level difference can affect adversely the operational stability of the waterwheel rotator system.Under the same working condition,increasing number of blades can suppress the fluctuation of torque but reduce the power output.Torque fluctuation is due to the action of imbalanced moments experienced by the waterwheel in operation,which may result in severe vibration of the waterwheel structure and fatigue damage to the blades.

关 键 词：水车性能 叶片数 明渠无压流 流体体积模型 微水头发电 

分 类 号：S277.9[农业科学—农业水土工程] TK37[农业科学—农业工程]