| Because of the tangent pump's performance advantage in small flow and super-low specific speed, Tangent pump gradually applied in industrial and civil fire field. The research on tangent pump is gradually from the high speed to the normal speed, and the application of the tangent pump in more and more wide range of application and promotionThis study design the tangent pump of the parameters using the modern pump design theory in order to study the design method. And choose the model of (QX2×130-7). Through the research on the numerical simulation methods and compare the results of steady,unsteady and experiments, draw the conclusions that the numerical simulation method is reliability and unsteady numerical simulation is better that steady result. According to this, using the unsteady numerical simulation method change the single parameters of the tangent pump, such as:laryngeal diameter, spiral and cross-section shape and side clearance. Through the research on the instantaneous flow characteristic curve and the internal flow characteristics:1.Using modern design theory design the parameters of (Q= 7m3/h, h= 260m, n = 2900rpm) model pump. through calculation and analysis the external characteristics within the scope of small flow and compara that with the result of experiments,draw the conclusion that the unsteady turbulent model is more suitable for the tangent pump internal flow field analysis in small flow range2.Through the analysis of the instantaneous characteristics of the tangent model pump in the scope of small flow(0m3/h-1.5Qdm3/h)and found that the model pump has the unsteady characteristics, with the increase of the flow, the instantaneous characteristics changes, and the unsteady characteristics significantly enhanced3.1n the conditions of only change the throat diameters,Through analysis find that:The port near the pump export has great influence on the pump performance; the flow of regional decide thechanges of the shaft power trend. The position of rotating impeller has greate influence on the instantaneous head and the instantaneous efficiency. With the totate of impeller, the head and the efficiency changed periodicly.4.1n some flow ranges,The throat diameters set as Dd, When the tangent pump throat diameter under 0.8Dd, the head and efficiency decreases rapidly. When the throat diameter more than 1.4 Dd, head and efficiency slightly higher than the design condition, but increase rate is small. Throat diameter size decide flow cut-off point, the bigger the throat diameter the bigger the deadline5. In some flow ranges and the condition of only change the cross-section of the volute. Average efficiency of Circular cross-section volute 0.63% higher than rectangular section. The lowest average efficiency of pear-shaped section volute lower 1.0% than that of circular section volute. But the highest average efficiency of pear-shaped higher 1.2% than that of circular cross section volute. And the average shaft power has little diference. The shape of cross-section has litlle effect on the performance of pump, so it can be choiced by the structure and manufacture6. In some flow ranges and the ideal conditiongs of the clearance. With the increase of clearance, the head,efficiency and shaft power has different level descend. While the clearance more than 0.3 mm, head decline sharply. With the flow increase efficiency changes magnifily... |
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