安徽快3开奖结果Characteristic curve of slurry pump various losses in centrifugal pump
1、 Various losses in centrifugal pump
1. Mechanical loss
Mechanical loss power △ PM mainly refers to the wheel disc friction loss caused by the friction between the impeller outer disc and the liquid △ PE, the friction loss between the shaft and the bearing △ P1, and the friction loss between the pump shaft and the seal △ P2, etc. (as shown in Figure 1-26
Among the mechanical losses, the friction loss of wheel disc is the largest. The friction loss between the bearing and the seal is related to the structure of the bearing and the seal and the properties of the conveying fluid, but its value is smaller than that of the wheel disc, which is 1% ~ 5% of the shaft power.
The above mechanical losses are almost independent of the flow rate when the liquid property, impeller and bearing structure, speed and so on are fixed, and they can be regarded as constants approximately.
2. Leakage loss
Because there is a gap between the rotating parts and the static parts of the pump, when the pump is working, the liquid at both ends of the gap will produce a pressure difference due to the difference in the energy obtained, resulting in the leakage of some liquid from the high pressure side to the low pressure side through the gap, which is called leakage loss or flow loss。
Leakage loss mainly occurs in the clearance between impeller ring and pump shell, the clearance between guide vane diaphragm and shaft sleeve, the clearance between axial force balancing device and pump light, and the clearance at shaft seal, as shown in Figure 1-27。
The theoretical flow into the impeller Q, can not be discharged from the pump outlet, there will always be a small part of leakage。 If q is the leakage flow, then the leakage q is related to the head H。 Practice has proved that q = f (H) is a conic curve, because the general Q value is very small, the curve is relatively steep。 See Figure 1-29, curve 8。 Therefore, the discharge flow Q of the pump has the following relationship with the theoretical flow: slurry pump manufacturer
3。 Current loss
The flow loss in centrifugal pump includes friction loss and impact loss.