Visual Simulation Of Flow Field Inside Dual-nozzle-flapper Electro-hydraulic Servo Valve

Electro-hydraulic servo valve is a complex electro-hydraulic component. It is the bridge of connecting electrical and hydraulic parts and the core component of electro-hydraulic servo control system. Dual-nozzle-flapper electro-hydraulic servo valve has some advantages, such as, small volume, high power magnification, good linearity, small dead zone, fast response, stable and reliable operation, etc. So it has been very widely used in a variety of electro-hydraulic servo system. Therefore, the research to characteristics of dual-nozzle-flapper electro-hydraulic servo valve is of great significance for correct design and use electro-hydraulic servo valve.In this article, according to actual situation, three-dimensional geometric models are established with solidworks software when spool is in a variety of different states and nozzle flapper is at different locations. The geometric models are imported to pre-processing software and edited, so that the three-dimensional model are generated and meshed. Finally, the visual simulations of flow field inside valve and nozzle flapper are accomplished with software when spool was stationary.First, the simulation of flow field inside main valve of dual-nozzle-flapper electro-hydraulic servo valve is accomplished with software. Based on the results of simulation, comparing the path line, velocity distribution, turbulent kinetic energy and pressure distribution inside slide valve when the flow rate is the same, and the opening degree of valve port is different, it offers the practical significance for qualitative analyzing the energy loss and the noise within the slide valve and optimal designing the structure and flow channel of slide valve.Second, against the high demand on oil cleanliness of dual-nozzle-flapper servo valve, the simulation of flow field inside main valve of dual-nozzle-flapper electro-hydraulic servo valve is accomplished when slide valve port is blocked in different situations. Through analysis and comparison of the velocity and pressure distribution, the specific circumstances which offers reliable basis for fault diagnosis of servo valve can be very intuitively understood when the valve port is blocked.Finally, the simulation of flow field inside double-nozzle baffle which is the pilot level of dual-nozzle-flapper electro-hydraulic servo valve is accomplished. Analyzing and comparing the velocity, pressure distribution when baffle at different position, it offers the basis for analyzing and calculating the influence of various factors on flow field, such as nozzle diameter, length, diameter of the back pressure cavity, etc, and provides the practical significance for qualitative analyzing the energy loss and the noise within the flow channel and optimal designing the structure of flow channel.After simulation with software, the results are verified by theoretical formula and consistent with theory. By contrast, the calculations of Fluent are convenient. For different situations, characteristics of electro-hydraulic servo valves which provide basis for optimal design of servo valves can be analyzed quickly and reliably as long as the corresponding models are established.