Screw Water Pump Using a Scalable Rotary Heat Engine that Uses a Spontaneous Motion due to an Asymmetrical Heat Transfer

Abstract

A simple and strong micro heat engine that converts heat energy into mechanical work is a core technology for innovative microfluidic circuits and microrobots. However, it might be difficult to use a micro engine that can work only under a micro size. Thus, we propose a scalable simple rotary heat engine that converts thermal energy into rotational kinetic energy around a fixed axis using self-propelled motion due to a spontaneous asymmetrical heat transfer; and demonstrate its applicability to a water pump with a screw. Specifically, we find that by the application of a DC voltage, a nichrome wire having a zigzag structure with a screw rotates with an angular velocity of up to ∼8 rad/s around a fixed axis due to the self-propulsion phenomenon in a rectangular flow channel, and produces a net flow with a velocity of up to 6 mm/s. Our pump should contribute innovative microfluidic circuits and microrobots in the future.