From our daily life, we know that the current will force it to change the direction of the object. For example, when the water flow in the pipe is 90 degrees, the water flow can impact on the elbow. The well pump, in the liquid through the Kalachakra, not only the magnitude of velocity in a constantly changing, and the direction of flow by inlet axial shift for the exit of oblique (of mixed flow impeller) or radial (of centrifugal impeller). The impeller as a result of forced flow direction change, also changed the direction of flow, so that water on the impeller produced a to (i.e. axial momentum). According to the physics of momentum theorem knowable, the momentum of the size and impeller inlet flow velocity of or quadratic of the pump flow is proportional to the. In the well pump start early outlet pipe gradually filled with water, then the pump head is very low, down the pressure of water is very small, but the pump flow greatly, so on momentum also, the pump shaft suddenly channeling; with the improvement of outlet pipe of water filling and head, flow is decreased, the momentum is also reduced, the pump shaft on the channeling phenomenon immediately disappear. And if the pump before the start, has been filled with water in the pipe, then the channeling is not obvious or even disappear.
In addition, when well pump in the large flow and low head run, or the high lift pump for low lift pumping will due to the increase in flow caused by the increase of momentum, causing the pump shaft and channeling. So it should avoid the running condition.
