CDH-125型无阀气动潜孔锤冲击系统动力学特性分析

Dynamic Characteristics Analysis of CDH-125 Valve-less Pneumatic Down-the-Hole Hammer Impact System

摘要:

本文针对CDH-125型气动潜孔锤冲击动力学过程进行研究，对无阀配气活塞运动过程中的受力状态进行了准确的分析，进而基于有限差分方法，对潜孔锤工作过程中的热力学以及动力学微分方程组进行迭代求解，得到潜孔锤活塞以及气室的动态工作特性，如：活塞位移和速度之间的相对关系，前、后气室的压力、温度交换关系等；应用多物理场仿真软件SimulationX对有限差分法求解结果进行对比验证，活塞冲程最大速度相差3%，回程最大速度相差19%，工作频率相差2%。基于上述结果，进一步对活塞与内缸之间气体黏性摩擦力进行计算与分析，结果可知：与无黏流体理想情况下进行对比，单一工作周期内黏性摩擦力使潜孔锤工作频率降低0.18%，使活塞的冲程最大能耗增加0.05-1.34J/次，黏性摩擦力对潜孔锤动态性能的影响不可忽略。

Abstract:

This paper studies the impact dynamics process of the CDH-125 pneumatic down-the-hole (DTH) hammer, accurately analyzing the force state during the motion of the valveless distribution piston. Subsequently, based on the finite difference method, the thermodynamic and dynamic differential equations of the DTH hammer during its working process are iteratively solved to obtain the dynamic working characteristics of the DTH hammer piston and air chambers. These characteristics include the relative relationship between piston displacement and velocity, and the pressure and temperature exchange relationships in the front and rear air chambers. The results obtained from the finite difference method were compared and validated using the multiphysics simulation software SimulationX, showing a maximum speed discrepancy of 3% for the piston stroke, 19% for the return stroke, and 5% for the working frequency. Based on these results, further calculations and analyses of the gas viscous friction force between the piston and the inner cylinder were conducted. The results indicate that, compared to the ideal situation with non-viscous fluid, the viscous friction force reduces the working frequency of the DTH hammer by 0.15% per working cycle and increases the maximum energy consumption of the piston stroke by 0.05-1.34J per cycle. The impact of viscous friction on the dynamic performance of the DTH hammer cannot be ignored.