Experimental Study On The Flow Pattern Of Open Pump Intake Under Non-uniform Coming Flow

Pump intake is designed and built to connect coming flow and the flange of theinlet of pump, its' main purpose is to lead the flow into inlet and impeller smoothlyand make pump work in high efficiency. Pump intake directly affects the efficiencyand security of the pump. In recent years energy requirement becomes emergentwhile the economy increases. However, pump, one among the mostconsuming-energy apparatuses, only has rather low efficiency in our countrycompared with international first class. In order to improve the efficiency of pump,study of the flow pattern and air-entrained amount in pump intakes is important.PIV system is applied to carry out the measurement of flow pattern in pumpintake in this experiment. PIV system's development is introduced and system's coretechnology is illuminated in the article. The reason why PIV system is used in theexperiment is also explained. The electric capacity air void meter is designed by usand adopted to measure air-entrained amount. Method through CCD capture is alsodesigned to accomplish this experiment. Furthermore, the two methods are comparedto confirm which one is better.The article analyzes the flow pattern of open pump intake when coming flow isnon-uniform. The results are concluded as below: (1)according to researchrequirement, system of open pump intake is designed and built by us;PIV system isadopted to measure flow pattern and then to get distribution of speed,turbulentintensity and vorticity;CCD method is adopted to measure air-entrained amount;(2) by analyzing the results of PIV, the conclusion is: more the coming flow ratioincreases, more vortices occur. The condition under which vortices occur mostfrequently is received. The curve of frequency is indicated to analyze the unsteadycharacteristic. Furthermore, the jet flow and the wake is analyzed;(3) the frequencythat entrained air bubbles occur at is received and the fraction of various size bubblesis gained. When coming flow ratio increases, more air bubbles are entrained and morebig bubbles occur.