表面织构型高频液压冲击活塞副耗能机理及设计优化研究

The mechanical and leakage loss between the piston and the cylinder is an important factor affecting the energy efficiency of the hydraulic impactor. The surface texture of the impact piston can change the flow law of the oil, which can cause the lubrication and heat transfer state change of the impact piston pair, and finally lead the change of the mechanical and the leakage loss making energy efficiency vary. The piston with surface texture is used in the project to improve the lubrication and seal conditions. The mechanism of declining energy dissipation for impact piston pair and design of piston with surface texture will conduct as follows: (1) The physical mechanism of high frequency hydraulic impactor piston pair with surface texture is analyzed. The mathematical model of fluid solid heat coupling is developed, and the evolution law of friction and seal for piston pair is investigated; (2) The relation of structure parameters, motion parameters, and surface texture parameters for piston to energy dissipation parameters are analyzed. The effects of surface texture to decline energy dissipation are studied, and the mechanism of declining energy dissipation for hydraulic impact piston pair is revealed; (3) Based on the experimental method and least square support vector machine, a quantitative model of the piston structure and its surface texture parameters to the energy dissipation of hydraulic impactor is established, and optimization design with object of minimum energy dissipation is carried on. This project makes the energy dissipation mechanism of hydraulic impact piston pair with surface texture be revealed, and provide a theoretical basis for the design of high efficiency hydraulic impactor.

冲击活塞与缸体之间的摩擦和泄漏损失是影响液压冲击器能量利用率的重要因素。合理的冲击活塞表面织构能改善油液流动规律，降低摩擦、泄漏损失提高冲击器能量利用率。项目拟采用表面织构液压冲击活塞改善润滑与密封条件，围绕降耗机理及表面织构活塞副设计开展研究，主要内容包括：(1)分析具有表面织构液压冲击活塞副综合能耗产生的物理力学机制，开展表面织构型液压冲击活塞副流固热耦合数理建模与活塞副摩擦密封特性演变规律分析；(2)分析冲击活塞副结构和表面织构参数，以及运动参数等与活塞副的摩擦力、温度分布、膜厚和泄漏量等摩擦密封特性参数之间关系，研究不同表面织构能耗抑制作用，揭示表面织构型液压冲击活塞副的降耗机理；(3)基于实验设计法和最小二乘支持向量机建立活塞结构及其表面织构参数与液压冲击器能耗定量关系模型，以能耗最小为目标开展优化设计。本项目将深化液压冲击活塞副能耗机理认识，为设计高能效液压冲击器提供理论依据。

本项目以高频液压冲击器为研究对象，旨在提高液压冲击器能量利用率，利用表面织构破解传统活塞副低能耗设计困境，应用机械、物理、计算机、统计学等多学科理论与方法开展研究工作。项目综合考虑冲击活塞副的泄露与摩擦损失，提出了综合能耗评价指标；利用平均雷诺方程构建了织构型高频液压冲击活塞副的综合能耗分析模型，分析获得了额定工况下活塞织构参数对综合能耗的影响规律；基于N-S的扩展雷诺方程、弹塑性变形方程等流体力学理论，采用有限差分法，建立了流体-结构耦合的织构活塞副润滑数学物理模型；以高频液压冲击器中的织构型冲击活塞副为研究对象，对不同类型织构活塞副能耗进行求解分析，建立了相关参数与综合能耗的映射关系；利用函数特征逼近和坐标变化建立了复杂织构（如仿鱼鳞型织构）凹坑截面的数学表征模型，结合织构化流体动压润滑原理建立了不同特征参数下织构凹坑三维流场数值分析模型，通过正交试验设计分析获得了鱼鳞型织构表征参数以及液压油流速对冲击活塞表面摩擦性能的影响规律；提出了采用电液伺服油源作为驱动源，自制活塞两侧供油，中间测泄露油的液压冲击器活塞副摩擦密封特性参数模拟测试实验装置，为织构型活塞副能耗分析结果的验证提供了设备支撑。项目发表论文10篇，其中SCI收录7篇；申请国内国际专利5项，获得授权国内发明和国际专利各1项；表面织构型低能耗冲击活塞副结构和设计技术已在液压凿岩机和沉桩设备成功应用，相关成果获得了湖南省技术发明三等奖。