Research On Churning Losses Of High Speed Piston Pump

With the rapid development of aerospace equipment,axial piston pump,as the core power component,urgently pursues the ultimate power/weight ratio,which makes the pump inevitably develop towards high pressure and high speed.However,the churning losses caused by the movement of the components in the pump increases sharply with the increase of the speed.This results in the high speed zone being an inefficient zone for the piston pump to operate in.Therefore,it is urgent to study the churning losses of high speed piston pump.At present,the influence of piston reciprocating motion on churning losses was ignored in most researches.And it is difficult to establish accurate and accurate energy consumption theory.Therefore,the churning losses theoretical model and measurement method are studied for the real movement of the pistons in this paper.The main work of this paper is to establish the theoretical model of churning losses in the reciprocating motion of the pistons,develop the visualization module for the full cycle flow field of the reciprocating motion,and investigate the influence of the flow around the square column in the reciprocating direction on the flow resistance around the side wall of the piston.The mapping relationship between composite motion churning losses and structural parameters and layout of pump components is analyzed.The churning losses test equipment which can realize composite motion and friction loss stripping is designed.The main research content of this paper is as follows:Firstly,the churning losses theory model and test method of axial piston pump are investigated.The deficiencies and technical difficulties of the current research are summarized,and the research content of this paper is put forward.Secondly,the passing flow resistance coefficient which can be used to characterize the flow field disorder state is proposed.The theoretical model of churning losses caused by piston high speed reciprocating motion is established.The variation law of stirring flow field in the whole movement period is revealed.The accuracy of the theoretical model of churning losses in reciprocating motion is verified by using particle image velocimetry technology to photograph the flow field.Thirdly,the theoretical model of churning losses caused by the pistons compound motion is established.The shielding effect between multiple pistons and the influence of reciprocating motion on the flow around the piston are investigated.The mapping relationship between the shielding effect and the Angle of swash plate and the relative distance between multiple pistons is solved.Combined with the analysis results of the passing flow resistance coefficient of the flow around the piston,the mechanism of the flow around the piston under the complex dynamic behavior is revealed.Finally,a test pump which can realize the piston combined movement and the decoupling test of churning losses is proposed.The test pump is used to test the fluid resistance coefficient and churning losses,and the shielding resistance coefficient is further solved.The test results were compared with the theoretical analysis results to verify the accuracy of the theoretical model of churning losses caused compound motion.