| U-shaped throttle groove slide valve is a kind of non full circumference opening slide valve.Its remarkable structural feature is that several U-shaped throttle grooves are set at the shoulder of the valve core.Because it has the advantages of convenient processing and strong control performance,it is widely used in engineering practice.flow force is the key factor affecting the service performance of U-shaped throttle groove slide valve.Therefore,this paper combines theoretical analysis and simulation analysis to explore the influence of key structural parameters of U-shaped throttle groove on flow force.The structural parameters are optimized according to the service performance of the U-shaped throttle groove slide valve,which provides a reference for the reasonable design of the structure of the U-shaped throttle groove slide valve.The main contents and conclusions are as follows:(1)The formulas of transient flow force and steady flow force on the spool valve of U-shaped throttle groove are deduced.Combined with the formula and threedimensional model,the key structural parameters of U-shaped throttle groove are determined as groove length L,groove width 2R and groove depth H;Through the orthogonal experimental design,the theoretical quantitative analysis of the test results combined with range and analysis of variance,it is found that the sensitivity of the key structural parameters to the influence of flow force is as follows: 2R>L>H at 20% opening,2R>H>L at 40%～100% opening;The significance of the influence of key parameters on flow force is as follows: H is not significant at 20% opening,L and 2R are significant;The three parameters are significant at 40%～80% opening;At100% opening,L is not significant,H and 2R are significant.(2)Single factor analysis is carried out for each key structural parameter to explore the specific changes of pressure distribution and flow field distribution in the valve body when a single structural parameter changes.It is found that when the valve opening is fixed,the variation law of flow force is as follows: 2R is always positively correlated with flow force;When h is 1.5mm ～ 2.3mm,it is positively correlated with flow force,and when H is 2.5mm,it is negatively correlated;When L is3.0mm～4.6mm,it is positively correlated with flow force,and when l is 5.0mm,it is negatively correlated.It is found that when the valve opening changes,the change of transient flow force is as follows: when the opening is 0%～40%,the direction of transient flow force tends to close the valve opening,and when the opening is40%～100%,the direction of transient flow force tends to open the valve opening.Finally,through dimensionless processing,the weight of the influence of each structural parameter on flow force is obtained,and the theoretical sensitivity ranking conclusion obtained in the range and variance analysis stage is compared with the actual weight obtained by numerical calculation.It is found that it is completely consistent.(3)In order to improve the control accuracy and fast response performance of the U-shaped throttle groove slide valve(maximize the flow at the valve port on the premise of ensuring that the hydraulic force on the valve core is small),combined with the variation curve of hydraulic force with opening,the variation curve of flow with opening and the sensitivity ranking law,Kriging surface interpolation method is used to interpolate and predict the hydraulic force and flow values corresponding to all throttle groove structures within the size range,The multi-objective optimization model is obtained;The evolutionary genetic algorithm NSGA-Ⅱ is used to globally optimize the multi-objective optimization model,and the Pareto solution set meeting the target requirements is obtained.Then the optimized U-shaped throttle groove slide valve is re modeled and CFD flow field simulation analysis is carried out.It is found that the optimized U-shaped throttle groove slide valve meets the requirements of target control accuracy and rapid response. |
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