液压支架换向阀的液动力计算方法及其应用

液动力计算模型是液压阀建模和特性分析的基础和前提,液压支架用换向阀流道复杂,其液动力的分析计算与常规液压阀不同,且这种复杂流道下的液动力大小不易通过试验测试得到,计算模型也无法得到较好的验证。为解决这个问题,建立了液压支架用换向阀的复杂流道模型,利用2个控制体将流道划分为两部分,采用理论计算与流场仿真的方法分别研究阀口处和阀芯折弯流道处的液动力,并根据流场分布特征对传统液动力计算公式进行修正,得到了相应的修正系数;而在液动力的验证方法上,不采用传统的直接测试法,而是分别将修正前和修正后的液动力计算公式/min的换向阀数学建模中,通过对比2种情况下换向阀动态特性的仿真结果与试验结果,间接验证液动力修正模型的准确性,避免了直接测试法在应对复杂流道问题时的不足。2种情况下的动态特性仿真与试验结果对比显示,采用修正后的模型进行仿真得到的动态特性与试验所得数据非常接近,而用未经修正的传统计算模型得到的仿真结果与试验结果存在较大的误差,此结果说明了液动力修正模型的准确性,同时验证了复杂流道液压阀的液动力计算方法与试验方法的合理性。本文在液动力的理论分析与试验验证两方面均有不同,并结合工程实际对所用方法进行了验证,提供了面对复杂流道液动力的解决办法。

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 theoretical calculation and flow simulation was used to study the flow force at the valve port and that at the turning channel.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 combination 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 accuracy 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.