Research Of Flow Field Or Dynamic And Static Character Of Double Jet Flapper Servo Valve

Hydraulic components, systems and the control of them, is a industry that lots of world's industrial developed countries strive to develop, and is considered an important indicator of the level of industrialization of a country, of which the performance of hydraulic components will affect overall system performance. China hydraulic industry learn from foreign developed technology which is the basis of our own manufacture of hydraulic components, processing system, having got great achievements. However, there are also some problems in the industrial development of the hydraulic, such as large lose of internal flow of energy, noisy, short-lived, for the design of hydraulic valves and piping less finite element analysis, usually based on experience, and the study of the effects on the shape of the flow field's performance of hydraulic components are rare, therefore, it is necessary that one should analyze the hydraulic components and piping the flow field based on modern numerical CFD tools and analyses relationship between the flow field of noise and the energy loss of the hydraulic valve based on the results.The main work of this thesis is the flow field's simulation and the analysis of double-nozzle flapper servo valve or main valve nozzle flapper-level and experimental test flapper valve in the static and dynamic characteristics of it. Firstly, this paper describes the relevant elements of computational fluid dynamics, including computational fluid dynamics of the solution steps and the main method of calculating fluid turbulence model and introduces the FLUENT model simplify. And then establish the flow field's model of two-nozzle servo valve and main valve nozzle flapper-level using INVENTER, the grid was carried out by using GAMBIT software. The shape of the flow field is established when the different displacements of the baffle and the different positions of main valve spool and analysis the possible impact of the hydraulic valve. There are larger energy dissipation at the location of the nozzle baffle, and major changes in speed, while the temperature has a larger increase here, when the main valve to get open in the valve port the liquid will have a greater change in velocity, the pressure change is greater here, the energy dissipation concentrated here, at the same time some improvements for the main valve are made, the valve-level analysis to improve the emperor of the flow field shape, and with no improvement before the flow field comparison, the improved spool into the valve chamber in the fluid when the velocity and pressure were significantly reduced.This paper introduces the classification of the servo valve, the working principle, and the static and dynamic performance parameters. And establish the mathematical model of the servo valve; research its dynamic and static performance through MATLAB simulation. The valve leak, no-load flow curve, pressure characteristic curve, resolution and a series of static characteristic curve is attained by the experiment, finally, test the double-nozzle flapper servo valve dynamic performance, by the time domain and frequency domain response curve was servo valve bandwidth amplitude and phase bandwidth, attain its frequency range.