无阀微泵动态特性的固液耦合分析

Solid-liquid Coupling Analysis of Valveless Micropumps Dynamic Characteristics

根据无阀微泵的工作原理,对泵膜—流体耦合振动过程进行理论分析,推导出此状态下的非线性耦合振动方程。并采用伽辽金加权最小余量法得出方程的近似解。在此基础上讨论阻尼系数、驱动力及薄膜固有频率与薄膜振幅、相位差及无阀泵流量的关系。理论分析表明在阻尼系数较小时,在一阶固有频率附近还存在振幅增大的现象,随着阻尼系数的增大,流体对泵膜的阻力逐渐增大,振幅随着频率的增大迅速衰减,相位差也越来越快地靠近90°;驱动力一定的情况下,薄膜的固有频率越低,薄膜在低频段振动可以达到的振幅越大;对于流量而言,在低频段,流量很快就达到极大值.而且阻尼系数越大、泵膜固有频率越低、驱动力越大,流量越快到达极大值。

According to the working principle of valveless micropumps, the theoretical analysis of membrane-fluid coupling vibration process is carried out and a non-linear coupling vibration equation is developed. The approximate solution is obtained by using Galerkin weighted minimum residual method. And the relations among the damping coefficient, the driving force, the natural frequency of membrane and the amplitude of membrane, phase difference, and the flow rate of valveless pumps are discussed. Theoretical analysis shows that when the damping coefficient is small, the amplitude increases near the first order natural frequency. With the increasing of damping coefficient, the resistance of fluid increases gradually on the membrane. At the same time, the amplitude decreases rapidly and phase difference tends to 90° faster with the increasing frequency. When the driving force is certain, the lower the first order frequency of the membrane is, the greater the amplitude can achieve in low frequency. As for the flow rate, it will reach the maximum value quickly in low frequency. Moreover, the greater the damping coefficient is, the lower the natural frequency of pump membrane is, the greater the driving force is, the flux will reach its maximum value more quickly.