Research on a large power thermal bubble micro-ejector with induction heating

The present study investigates a large power thermal bubble micro-ejector with induction heating device. The traditional thermal-bubble ejectors adopted resistors as the heating resources, it can only work with lower power and convey liquid with lower flow rate. Induction heating devices are adopted to replace the resistor for heating liquid in this paper. With this heating method, there is no physical contact between the heating core and the external power supply circuit. The liquid in the chamber of micro-ejector is heated by the induction heating device and changes from liquid phase to gas phase, generating vapor bubbles in the micro chamber of the micro ejector. The bubble expands rapidly and ejects droplets through the nozzle. The prototype of the micro-ejector is fabricated and experiments are carried out. Continuous droplets are ejected out from the nozzle as the applied AC current is 0.6–0.65 A with the power frequency of 100 kHz. The total volume of the continuous droplets is ranging from 18.84 to 49.87 nL, and the corresponding flow rate is about 0.52–1.36 μL/min. Furthermore, this new micro-ejector can be adopted in conveying of micro-scale liquid, the injection of trace drugs and the 3D printing.