Key Technologies Research For Air Motor Used In Propeller Power Simulation

Air motor is a new kind of power simulator for propeller.It is driven by compressed air,and converts internal energy of high pressure gas into rotating mechanical energy so that to propel power simulation wind tunnel test of model propeller.It has the characteristics of small size,high power,and the core engine is multistage axial turbine.This paper focuses on several key technologies of AEF 0228 A air motor,the main works include the following.Firstly,domestic and foreign development situation of propeller power simulation was summarized,and the advantages and necessities of air motor for propeller power simulation was told.The author pointed out some key technologies of air motor research,and stated the main works of the paper.In chapter two,the aerodynamic performance of multistage axial turbine was evaluated as the core engine of AEF 0228 A air motor.The performance evaluation was under the numerical method of CFD,the results of which matched the test results well,then the numerical method was verified as a result.During the analysis on flow field of the turbine,the efficiency of the first stage was found as low as 50.9%,and the flow field of the first stage was unreasonable.Therefore,in order to achieve the optimization objective of improving the stage efficiency,the first stage rotor was chosen for the aerodynamic optimization design technology.Aerodynamic optimization design technology of multistage axial turbine was studied in chapter three and chapter four.In chapter three,the parametric fitting of the original turbine was carried on,and the performance of the parametric blade was compared with that of the original blade,resulting with an error within 0.1% which verified the parametric fitting method.The installation angle,the inlet angle and the blade profile were confirmed by means of parametric fitting.Comparing parameters in the database built by numerical calculations,the relations between the parameters and their performance were summarized and the optimization parameters were confirmed.In chapter four,with the optimization parameters confirmed in chapter three,evolutionary algorithm-based optimization design was made.Optimization results of different objective functions were compared,confirming an optimization result which was a joint optimization of the installation angle and the blade profile,and maximized the efficiency penalty function.Comparing with the original turbine,the optimization results improved the stage efficiency from 50.9% to 60.5%,the total efficiency from 52.9% to 55.3%,the total power was enhanced from209.2k W to 218.57 k W.In chapter five,the safety performance of AEF 0228 A air motor was evaluated.Through modal analysis on two typical loads by means of rotor dynamics method,the first critical speed of the second typical load was confirmed to be inside the work speed of the air motor,which meant sympathetic vibration would be possible while working.Finally,the steady response of the rotor system on unbalance quantity was evaluated,the results showed that the steady response of the rotor system was safe under the power balance accuracy of G6.3.