Choice of pump speed. According to the principle of the water supply pump, the pump pressure and the speed of the square is proportional to the flow rate and the speed of a Fang Cheng proportional. Therefore, to advance the water supply pump single stage head, the most reasonable, the most convenient way is to advance the pump speed. The rotational speed of the rotating shaft can be reduced, and the length of the rotating shaft is shortened, so that the flexible shaft can be changed into a rigid rotating shaft. The rigid shaft is better than the flexible shaft, it is not sensitive to the complex forces, even if the water pump is completely under the state of vaporization, and even under the dry, it will not attack vibration. However, the general water pump is directly driven by a condensing turbine, and its speed is restricted by the limit speed of the turbine.
Under the given design parameters, the size of the pre swirl is related to the inlet angle of the blade, the flow rate of the impeller and the circumferential speed of the impeller. On larger imports neck diameter, should choose strong pre swirl and larger blade protruding and distorted; for smaller imports neck diameter, should choose weaker pre swirl and smaller blade protruding. Blade to the appropriate import extended intention is to add the blade channel partially effective length, reduce the blade loading, the power of progress leaves, add head, improve the cavitation, reduce benefits at the inlet of the hydraulic loss and the stability of the pump function were. Taking into account the effect of the rotation of the impeller in near the impeller inlet pre swirl has added to the trend, should make the back guide vane outlet end slightly distorted (about 35), and extends to the inlet of the impeller, to better adapt to the changes in the direction of liquid flow, and caused a point to the axial component of the impeller inlet, conducive to the flow of the impeller inlet. Pump hydraulic components manufacturing model, casting and processing and assembly quality is good or bad, often affect the pump power of 4%8%, and even more, should ensure that the quality of manufacturing progress.
