Design And Performance Research Of Forward-curved Channel Wave Rotor For Gas Wave Ejector

As the core component of gas wave ejection,the rationality of the wave rotor structure has a significant impact on the performance of the equipment.Therefore,this paper innovatively proposes a forward-curved channel structure in order to solve the problem of flow loss during the operation of the traditional straight channel wave rotor.Based on theoretical analysis and numerical simulation,the air flow movement and the inclination structure are analyzed and designed in detail.Build an experimental platform to study the influence of different working conditions and structural parameters on the gas wave ejection performance.The corresponding content and main conclusions are as follows:(1)According to the analysis of gas wave ejection theory,the gas movement state in each stage of the flow channel is determined.In order to reduce the interaction force between the wave rotor and the air flow and reduce the flow loss,according to the design method of the ratio of the tangent of the inclination angle of the inlet and exhaust side channels to the gas jet velocity and the rotational linear velocity of the flow channel,the forward-curved channel structural parameters are determined.(2)By establishing the forward-curved channel wave rotor numerical model to study the pressure wave and gas flow law during the gas wave injection process,it is found that the forward-curved channel wave rotor based on the theoretically designed dip structure can effectively reduce the energy loss caused by vortex and flow separation to improve the ejection performance.According to the forward-curved channel wave rotor with different inclination angles,the influence of various operating parameters on the inclination angle design and ejection performance is analyzed.It is found that with the change of pressure ratio and speed,not only the ejection performance changes significantly,but also the matching relationship between the channel inclination structure and the airflow motion and rotor rotation also changes,that is,the inclination angle matching with the largest performance improvement occurs near the design conditions.(3)An experimental test platform for the forward-curved channel wave rotor gas wave ejection was built to study the change rule of ejection performance under different operating parameters and structural parameters.Under the condition of constant speed,when the compression ratio is constant,as the expansion ratio increases,the equipment ejection rate and isentropic efficiency both increase first and then decrease;otherwise,when the expansion ratio is constant,as the compression ratio increases,the equipment ejection rate gradually decreasing,the isentropic efficiency first increases and then decreases.When the pressure ratio of each port is constant,as the speed increases,the ejection performance initially decreases due to the change in the matching relationship of the inclination angle of the channel,and then slightly increases due to the influence of the speed,but when it continues to increase,the inclination matching relationship seriously deteriorates and the flow loss increases,the ejection performance decreases.Comparing the experimental data of the straight channel wave rotor under the same working conditions,the forward-curved channel wave rotor 's ejection performance is better.Under the design conditions of the inclination angle,its improvement can reach 43%.With the deviation of the high and medium pressure port deviation from the design value,the device's ejection performance is significantly reduced,which proves the rationality of the port design method based on the ideal wave diagram.As the inlet and outlet gap size increases,the leakage increases,the ejection performance decreases,and compared with the exhaust side gap size,the intake side gap size has a greater impact on performance due to the mixing of high and low pressure gases.(4)Using the three-dimensional numerical calculation of the forward-curved channel wave rotor,it is verified that compared with the straight channel structure,the new structure can effectively avoid the generation of the low pressure area of the leading edge in the flow channel,and reduce the degree of gas interface distortion,which meets the theoretical design goals.Changes in the inclination structure parameters,intake pressure ratio,and runner speed will cause the ideal inclination angle matching to change to some extent,which will cause the flow state to deviate from the optimal design conditions.