Calculation method of flow force for the directional valve used on hydraulic roof support and its application

The calculation model of the flow force is the basis of modeling and dynamic analysis of a hydraulic valve. However,the flow passage of the directional valve used on the hydraulic roof support is complex,so the calculation method of the flow force is different from that of the conventional valves,and it is difficult to verify the flow force model through the direct test of flow force under such conditions. In order to solve this problem,the complex flow passage model was established,and two control volumes were used to divide the model into two parts. The combination of theo- retical calculation and flow simulation was used to study the flow force at the valve port and that at the turning chan- nel. The flow force calculation formula was modified according to the distribution characteristics of the flow field and the corresponding modified factors were obtained. On the verification method of the flow force,the indirect method which tests the dynamic characteristics of the valve was used instead of the conventional direct method which focuses on the direct test of flow forces. When the 1 000 L / min directional valve of the hydraulic roof support was designed, the modified formula and the unmodified model of the flow force were applied to its mathematical model. The effects of the modified model and the unmodified model on the valve dynamic characteristics were compared through the combi- nation of simulations and experiments so as to verify the accuracy of the modified model. The new method avoids the shortcomings of the direct method in dealing with complex flow passage model. The comparison between the simulations and the experiments in the two cases shows that the simulation dynamic characteristics of the valve using the modified formula are close to the experimental results while there is great difference in the other cases. Results illustrates the ac- curacy of the modified flow force model,and verifies the rationality of the calculation and tests methods of the flow force for the valve with complex flow passages. The methods of theoretical analysis and experimental verification are all different from others,and they are verified in the practical engineering application. It provides solutions for the flow force of hydraulic valve with complex passages.