Research On Jet Quality Evaluation Index Of Servo Valve Nozzle And Design Of Its Testing System

The double nozzle flapper valve is an important control components widely used in aerospace control systems,in which the process detection of the important component nozzle of the pilot stage is crucial.Existing nozzle pressure and flow detection technology is very mature,but it lacks the definition of various jet forms,lacks reference for the related indicators of nozzle jet detection,and lacks the experimental equipment for nozzle jet detection.At the same time,the influence of the nozzle jet forms on the performance of the servo valve has not been studied.It is urgent to define various jet forms,clarify the impact of various jet forms on the pilot stage flow field,and design jet detection equipment to replace the traditional manual detection to improve detection efficiency.First of all,this article starts from the jet forms of nozzle jet,by analyzing the nozzle jet principle,based on the FLUENT software,the model of the internal and external flow field of the nozzle jet is established;by changing the geometry of the nozzle,various types of jet forms are classified and defined;Combined with the results of numerical simulation,the relevant characteristics of various jet forms are obtained and the comprehensive analysis of the optimal jet distance of jet nozzle.Secondly,the flow field of the pilot stage of the double nozzle baffle valve was discussed,and the cause of the cavitation phenomenon in the pilot stage was analyzed,and get the location of cavitation phenomenon;various jet models are added to the pilot-stage flow field model.The pilot-stage flow field of the nozzle oblique,scattering and spiral jets is analyzed in turn,obtain the best oblique angle,scattering angle and other indicators by compared with the standard pilot-stage flow field.Thirdly,study the existing nozzle jet detection process,and propose the overall design requirements of the nozzle jet detection equipment.Through the modular processing of various functions,the overall structural design and the calculation and selection of optical components have been completed.Finally,write the relevant algorithm of jet image detection,obtain the length of the jet oil in the image through the actual size measurement algorithm,and identify and classify various jet forms through the classification algorithm;design a simple experiment to obtain the length and angle information of the nozzle jet,verify the feasibility of the above algorithm.