渣浆泵泵中的径向力、轴向力及其平衡
一、径向力的产生及其平衡
    在设计流量时，蜗室内液体流动速度和液体流出叶轮的速度(大小和方向)基本上是一致的，因此从叶轮流出的液体能平顺地流入蜗室，在叶轮周围液体的流动速度和压力分布是均匀的，此时无径向力。但在小于设计流量时，蜗室内液体流动速度将减慢。从图2-49叶轮出口速度三角形中可以看出，此时液体流出叶轮的绝对速度2并不是减小了反而是增加了，吃>，并且方向也发生了改变。一方 面蜗室里的流动速度减慢，而另一方面叶 轮出口的流动速度增加，就发生了撞击，结果使流出叶轮液体的速度下降到蜗室里的流动速度，同时，把一部分动能通过撞击传给了蜗室内液体，使蜗室里的波体压力升高。液体从蜗室前端(隔舌)流到蜗室后端过程中，不断受到推击，不断增加压力，使蜗室里压力分布成逐渐上升分布。同样在大于设计流量时，蜗室里液体压力从隔舌开始是不断下降的分布。

由于蜗室各断面中的压力不相等，液体作用于叶轮出口处的圆周面上的压力不相等，于是在叶轮上就产生了一个径向力。又因为蜗室里液休的压力对流出叶轮的液体起着阻碍作用，由于压力不均匀，液体流出叶轮的速度也是不一致。因此，叶轮周围上受液体流出时的反冲力也是不均匀的。这又形成了径向力产生的另一个原因。 总之径向力是因为在非设计工况时由于蜗室压力分布不均匀而产生的。
    径向力会使轴产生较大的挠度，致使叶轮密封环、轴套等处卡死或磨损。同时会使轴因疲劳而破坏，在泵的运转中产生振动噪声。因此，消除径向力是十分必要的，特别是口径较大、扬程较高的泵。
    径向力平衡方法是将蜗室分成两个对称的部分，即双层蜗室或双蜗室，如图2-50所示。在双层蜗室里，虽然每个蜗室里压力分布仍是不均匀的，但由于两个蜗室相互对称，所以作用在叶轮上的径向力相互抵消。
    在蜗壳式多级泵里，采用相邻两个蜗室旋转180°布置的办法， 也可减弱径向力对轴的作用。

采用导叶式泵，由于导叶叶片沿圆周均匀分布，各个导叶所产生的径向力相互平衡了.渣浆泵厂家

Radial force, axial force and balance in slurry pump

I. generation and balance of radial force

In the design flow, the liquid flow velocity in the volute chamber is basically the same as that of the liquid flowing out of the impeller (size and direction). Therefore, the liquid flowing out of the impeller can flow smoothly into the volute chamber. The distribution of the liquid flow velocity and pressure around the impeller is uniform, and there is no radial force at this time. However, when the flow rate is less than the design flow rate, the liquid flow rate in the cochlear chamber will slow down. As can be seen from the triangle of impeller outlet speed in Figure 2-49, the absolute speed 2 of liquid flowing out of impeller at this time is not reduced but increased, and the direction is also changed. On the one hand, the flow speed in the cochlear chamber slows down, and on the other hand, the flow speed at the outlet of the impeller increases, resulting in an impact. As a result, the flow speed of the liquid flowing out of the impeller decreases to the flow speed in the cochlear chamber. At the same time, a part of the kinetic energy is transmitted to the liquid in the cochlear chamber through the impact, which increases the pressure of the wave body in the cochlear chamber. In the process of fluid flowing from the anterior end of the cochlear chamber (septum tongue) to the posterior end of the cochlear chamber, the pressure is constantly pushed and increased, which makes the pressure distribution in the cochlear chamber gradually increase. Similarly, when the flow rate is larger than the design flow rate, the liquid pressure in the cochlear chamber begins to decrease from the septum tongue.

Because the pressure in each section of the volute chamber is not equal, and the pressure of the liquid acting on the circular surface at the outlet of the impeller is not equal, a radial force is generated on the impeller. And because the pressure of the liquid rest in the volute chamber hinders the liquid flowing out of the impeller, the speed of the liquid flowing out of the impeller is also inconsistent due to the uneven pressure. Therefore, the reaction force around the impeller when the liquid flows out is also uneven. This is another reason for the radial force In a word, the radial force is caused by the uneven pressure distribution in the cochlear chamber.

Radial force will make the shaft produce larger deflection, resulting in the impeller seal ring, shaft sleeve and other places stuck or worn. At the same time, the shaft will be damaged due to fatigue, resulting in vibration and noise during the operation of the pump. Therefore, it is necessary to eliminate the radial force, especially for the pump with large diameter and high head.

The radial force balance method is to divide the cochlear chamber into two symmetrical parts, i.e. double or double cochlear chambers, as shown in Figure 2-50. In the double-layer volute chamber, although the pressure distribution in each volute chamber is still uneven, the radial forces acting on the impeller cancel each other because the two volutes are symmetrical to each other.

In the volute type multistage pump, the radial force on the shaft can also be weakened by adopting the method of 180 ° rotation of two adjacent volute chambers.

With guide vane pump, the radial force produced by each guide vane is balanced due to the uniform distribution of the guide vane along the circumference. Slurry pump manufacturer