The Analysis On The Water Direct-Actuated Relief Valves' Pressure Characteristic

Water hydraulics operated by fresh water or seawater instead of mineral oil is a hydraulic technology,which has become more and more attractive owing to the great advantages such as environmental friendliness,non-flammability,cheapness and easy disposal.However,the applications of water hydraulics should be based on the outstanding water components.The flow characteristics of throttles have great effects on the performances of the water hydraulic system,and are the bases of developing them. This paper carries out the thorough analysis and research to the pressure characteristics of the water direct-actuated relief valves by experiment and simulation.Firstly we get the entity model of the four types of valve cores, then we setup the mathematical model of the four types of valve cores and and the model are simulated with MATLAB/SIMULINK. It is a direct method to study the characteristic of the four types of valve cores. To verify entity model of the four types of valve cores, we do the site experiment of the water hydraulic relief valves and get the results of comparison and analysis for simulation and experimental.It can give guidance to the designer and save a lot of time and sources.Chaper one is the introduction,which includes technology,development status and technical solutions faced to resolve of water hydraulic.In the chaper two ,by some given design requirements and experimental requirements,it designs the water hydraulic relief valve.The design includes structional design,size-setting and the estimate of static capability.Ultimate we have designed a water hydraulic relief valve which is 142mm long and suitable for four types of valve cores and two types of valve seats.Its nominal pressure is HMPa.In the chaper ,with the analysis of various acting forces on the valve cores and the achievements in the flow coefficient about the four types of valve cores,we have established mathematical model and the system simulation diagram is described and runs in the MATLAB/SIMULINK.Then we get the results which are caused by the parameters of valves. In the chaper four ,the test includes the introduction and reconstruction of the experimental system,static performance tests and dynamic performance tests.Static performance tests contains the leakage of four types of valve cores,the range of pressure fluctuation and pressure stability,open-close performance experiment,pressure drop experiment, pressure oscillation and pressure-flow characteristic experiment; dynamic performance tests contains the step pressure response of four types of valve cores on the condition that four types of valve cores and two types of valve seats were applied.With comparison and analysis for simulation and experimental results, the simulation model is corrected.The influence of the components of four types of valve cores on the pressure characteristic are generalized and the structure design of relief valves are discussed based on the analysis above, which offers reference of water direct-actuated relief valves' design.