渣浆泵的特性曲线离心泵中各种损失
一、离心泵中各种损失

1. 机械损失

机械损失功率△Pm主要指叶轮外盘而与液体之间的摩擦而引起的轮盘摩擦损失△Pe、轴与轴承之间的摩擦损失△P1，以及泵轴与密封件之间的摩擦损失△P2等(如图1- 26所
示)，即有:
                           △Pm=△Pdr+△P1+ △P2  

机械损失中轮盘摩擦损失为最大。轴承和密封件间的摩擦损失与轴承和密封的结构型式以及输送流体的性质有关，但其值相对轮盘摩擦损失要小，为轴功率的1%~5%。
    上述机械损失，在液体性质、叶轮和轴承结构、转速等一定的情况下，几乎与流量无关，可将它们近似看作常数。

2.泄漏损失

由于泵的转动部件与静止部件之间存在间隙，当泵工作时，使间隙两端的液体因获得能头不同而产生压力差，造成部分液体从高压侧通过间隙向低压侧泄漏,这种损失称为泄漏损失或流量损失。
    泄漏损失主要发生在叶轮口环与泵壳间的间隙,多级泵级间导叶隔板与轴套之间隙处，轴向力平衡装置与泵亮间的间隙，轴封处的间隙等,如图1- 27所示。
    流入叶轮的理论流量Q,不可能全部从泵出口排出，总会有小部分泄漏。如果以q表示泄漏的流量.则泄漏量q与扬程H有关。实践证明,q=f(H)是一条二次曲线,因一般q值是很小的，故曲线较陡.见图1-29曲线8。因此，泵排出液体的流量Q与理论流量存在以下关系:渣浆泵厂家
                       Q=Qt-q
3.流动损失
    离心泵内的流动损失包括摩擦阻力损失和冲击损失等。

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

, namely:

△Pm=△Pdr+△P1+ △P2

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

Q=Qt-q

3. Current loss

The flow loss in centrifugal pump includes friction loss and impact loss.