颗粒流理论在建立NOPD能量耗散模型中的应用

Research of the energy dissipation mechanism of NOPD based on granular flow theory

为了研究颗粒进入对流状态时非阻塞性颗粒阻尼(NOPD)的能量耗散机理,引入颗粒流理论建立NOPD能量耗散的解析模型。借助离散单元法(DEM)初步研究了阻尼器内部颗粒的对流运动,引入普朗特混合长度理论对稠密颗粒流本构关系进行修正;借鉴振荡流理论最终得到NOPD的能量耗散解析模型。研究结果得到NOPD能量耗散率随颗粒参数变化的一般规律。在此基础上,搭建NOPD能量耗散功率测试实验台,对NOPD的能量耗散功率进行测试,验证了上述模型的正确性。研究结果进一步揭示了颗粒处于对流状态时NOPD能量耗散机理,为NOPD的应用提供了理论指导。

To study the energy dissipation mechanism and provide guidance to the application of NOPD,the granular flow theory is introduced to establish the energy dissipation model of NOPD.The convection of the particles inside the damper is studied using the discrete element method(DEM),and the Prandtl mix length theory is introduced to modify the constitution law of dense granular flow.The pressure in the granular flow is obtained by equate the vibrational excitation with the body force acted on the particles.It is shown that the energy dissipation rate of NOPD increases with the increase of vibration intensity,and decreases with the increase of granular diameter.It also indicates that particles near the side wall and the bottom wall of the damper dissipate more energy than particles in other regions.The model proposed in this paper can not only cast some light on understanding the energy dissipation mechanism of NOPD,but also provide some guidance to the parameter optimization of NOPD under different working conditions.