The relationship between impeller size, blade number and power, lift head, etc.
(b) similitude law of pumpsTwo pumps in line with similar conditions are set up below:Q2/Q1 = n2/n1 (D2/D1) fandH2/H1 = (n2/n1) - (D2/D1) -P2/P1 = (n2/n1) fand (D2/D1) 5 (p2/p1)Type Q1, Q2 - pump 1, pump 2 flow; N1, N2 - pump 1, pump 2, pump shaft speed;D1, D2 - pump 1, pump 2 impeller outer diameter; P1, P2 - pump 1, pump 2, shaft power;P1, P2 - pump 1, pump 2, density of conveying medium
Geometric similarity - the two pumps are structurally similar, with the same size, the same number of blades and the corresponding angle;Kinematic similarity - the flow of the fluid at the corresponding points in the two pumps is similar, and the velocity ratios are the same and in the same direction (i.e., the velocity triangles are similar);
First of all, we study the law of turning of the impeller, and combine the 3 formulas of the turning law, and use the similitude law and the relation of the specific speed(1) similarity law(a) similar conditions of pumps;
Definition formulaIn the design and manufacture of the pump, in order to have a variety of flow and lift pump were compared. The actual size of a pump, to reduce the geometric similarity as the standard pump, pump should meet the standard flow of 75L/s, head of 1m. At this point, the speed of the standard pump is the actual pump specific speed. Specific speed is a comprehensive and quantitative parameter derived from the similarity theory, which illustrates the relationship between flow, head and revolution. The dimensionless quantity than the number called form number, denoted by K than the number ns = 3.65n V Q
