Fluid-structure and electric coupled analysis of a valveless microfluidic system using metal-capped piezoelectric actuator

Abstract

A new actuator in which a metal cap is combined with a bimorph piezoelectric element was proposed, and the liquid transfer and mixing performance when applied to valveless microfluid devices was numerically verified. Especially to ensure high versatility, we aimed to be able to demonstrate sufficient performance with a general power supply of AC 100 V, 50 Hz in Japan. Two drive modes were considered: a single actuator applied only to the upper surface of the circular tank and double actuators applied to the upper and lower surfaces. In the liquid transfer performance test, it was found that the flow rate was improved by about 19 times in the single MC-BMP (Metal-Capped Bimorph) and about 82 times in the double MC-BMP compared with the conventional BMP (Bimorph). On the other hand, in the mixing performance test, it was found that the mixing index was improved about 2.3 times in the single MC-BMP and about 2.9 times in the double MC-BMP compared with the conventional BMP. Furthermore, protrusions were inserted into the flow path at the connection between the main flow path and the piezoelectric actuator, and the effect on the mixing performance was also verified. As a result, the mixing performance was greatly improved by inserting the protrusions, and finally, when two protrusions were inserted in the double actuation of the new MC-BMP, the mixing index reached 85%. From these results, we were able to verify the superiority of the proposed new MC-BMP, the usefulness and versatility that can be used with the general power supply of 100 V and 50 Hz. The findings can be expected to contribute to the design and development of pumps and mixers for various valveless microfluid devices.