Question

The centrifugal pump as described in Q5.8 is operating with a pre-whirl of 10° (i.e. Ui is inclined by 10° from the radial axis in the rotational direction). The centrifugal pump delivers 0.45 m3/s ofwater when it is running at the angular velocity of ω-1200 rpm Sketch the velocity triangles at inlet and exit of the impeller and hence determine the following items by assuming (a) negligible losses; and (b) Vi enters the impeller with θ| and V2 leaves with θε (i) Blade angle at the impeller inlet. (ii) Euler Head gain by the water flow after passing through the impeller bi Width of fluid flow passage at impeller inlet b2Width of fluid flow passage at impeller exit r Radius at impeller inlet r2 Radius at impeller exit 0.052 m 0.019 m 0.075 m 0.2 m | Blade angle at impeller inlet(angle between "ul," and "Vi") 02Blade angle at impeller exit (angle between "u2" and "V2") ABI | Fraction of circumferential area at inlet not blocked by blades A132 Fraction of circumferential area at exit not blocked by blades 60° 0.88 0.9

Answer 1

1200 x 2 2 v = 20.942 m/s

ci 냇 2. U) 20.563 20.868 4.425-3.6 Tnlet Blade amgle 3 U2 > ard CL) 20. SH1 25.133ャ20.14, Coso sim@2 25.153+ 20.48- 2g. 36 sim B Sim 29.36 曰.sz + 42.709 x34.224)