MULTI-PHYSICS COUPLING ANALYSIS AND EXPERIMENT OF THE VALVE-LESS MICROPUMP

For simulating the factual working process. The PZT-Membrane-Fluid multi-physics coupling governing equations of the micropump have been established, based on the piezoelectric transducer force F and the liquid counterforce P. Thusly, the actual working process can be simulated with the governing equations. The zdirection displacement of the piezoelectric transducer after coupling is less than before coupling because the counterforce of the liquid blocked the piezoelectric transducer movement. The displacement is larger along with the frequency enhanced, and the critical value is 1000Hz. When the frequency greater than 1000Hz, the displacement will produce aberrance, and the aberration becomes severity along with the frequency enhanced. The instantaneous flow rates will increase along with the voltage and frequency enhanced. However, the instantaneous flow rates of the saw-tooth micropump are larger than that of traditional micropump. Two micropumps have been fabricated with microsystem technology and encapsulated irreversibly by the ultraviolet radiation. The performance test of the micropump has been carried out. The result shows that the optimal working frequency is 100Hz~800Hz, and during this frequency range the flow rate and pressure lies in the condition of maximum values, which is consistent with the simulation result. For validating the self-priming ability of the micropump, the test also turned out that maximum flow rate and pressure head is 40 #x003bc;l/min and 1.25kPa respectively, through the experiment in the existence of a pressure difference.