The pump specific speed calculation formula

specific speed pump, the pump specific speed formula of the pump specific speed computing

similarity law shows only similar to the water pump in the similar point of the relationship between the performance parameters. Because of the different structure and hydraulic performance of pump impeller, the size of the size are different, in order to categorize the pump, the pump composed of a series of the same type, which requires a could reflect the comprehensive parameter of water pumps in common, as the basis of water pump normalization. The comprehensive parameter is pump than revolutions, expressed in ns. than the definition of revolution

under the rate, according to certain proportion to reduce the size of the pump ( Or expand) , making the effective power Pu = 0. 075 m3 / s, then, the model of the pump speed is called a similar to its actual pump than revolution. than the calculation formula of revolution

according to the law of similarity can be concluded that

3 · application pump than revolution formula problems that should be paid attention to

1 Q and H refers to the water pump, when the rate of flow and head n for the design of the pump speed. To the same pumps than revolution to a certain value.

(2) ( 225). The Q, H is refers to the single-stage single-suction centrifugal pump design flow and design head. For single stage double suction centrifugal pump with Q / 2 generation into the calculation; For horizontal or vertical multistage pump, multi-stage pump should be the primary impeller head in computing.

(3) than the revolution is about 20 ° C according to the pumping water.

(4) the parameters of the unit should be consistent with the model of the pump unit. Contrast revolutions discussion

1) for any pumps, revolution is not a dimensionless number. Because it is not the actual speed, it is only used to compare a common standard of various kinds of pump performance. As a result, its meaning not have much use, usually omit don't write.

(2) pumps than revolutions are according to the similarity relation, but which contains the actual pump main parameter Q, H, n,? Max value. Therefore, it reflects the actual pump main performance; Figure (from pump than revolutions formulas 2 - 25) Can be seen that: when the speed of the pump must be, the greater the ns, show that the flow of water pump, the lower the head, on the contrary, the greater the the smaller than the number of revolutions, show that the flow of water pump is smaller, the higher the lift.

(3) the shape, size, performance and efficiency of the pump impeller is over than revolution. Be classifying water water pump for than revolutions, as listed in table 21.

(4) the performance of the pump with better than revolution. Ratio of revolution and the shape of the water water pump performance curve is different also, with water pump than revolutions can analyze the performance of the pump.

related articles: submersible pump type and parameter