农用无过载离心泵水力性能与内部流动计算

试验研究证明水力效率偏低(比普通泵约低2％～8％)是无过载离心泵效率较低的主要原因。为了提高水力性能,对无过载离心叶轮内部流动进行了数值模拟。采用IKhalil等人的计算方法,在子午面上用势流计算确定流面位置,回转面的计算则采用了完全粘性的湍流场计算方法。结果表明,无过载离心叶轮内部流动既没有出现分离,也没有明显的尾迹区存在。因此,水力效率偏低系由叶片包角过大、流道狭长、沿程水力摩擦损失过大所致。

Hydraulic Performance and Flow Calculation of Non-overload Centrifugal Pump for Agricultural Use

It is proved by tests that the lower hydraulic efficiency (about 2%- 8% lower than ordinary) is the main reason for the lower efficiency of non-overload centrifugal pump. By I Khalill' s numerical method, in hub-shroud plane using potential flow calculation to determine flow surface position and in blade-blade plane using completely viscous turbulence calculation, the inner flow of non-overload centrifugal impeller is calculated. The result shows that there exists neither flow separation nor apparent wake flow within an non-overload centrifugal impeller. Therefore, the lower hydraulic efficiency attributes to the larger hydraulic friction loss due to the larger blade wrapping angle and the narrow-long flow passage.