Simulation and experiments for a phase-change actuator with bistable membrane

This paper introduces a new actuating method and explains the operating principles with simplified models and experiments. This novel idea is just a combination of two well-known distinct phenomena, phase-change heat transfer and bistability of a membrane. For the in-depth understanding about each mechanism and future applications into microfluidics, a simplified phase-change heat transfer model with n-pentane as a working fluid is provided, in which abrupt large volume change due to snapping movement of a bistable membrane is considered. The buckling characteristics of the polyethylene terephthalate (PET) membrane is explained with an approximated model by applying bistable beam theory into bistable plates to avoid any difficulties of three-dimensional non-linear problem. It is shown that calculated results of simplified models are similar to experimental results. These coupled distinct mechanisms prove that constant temperature difference can make repeated up-and-down movement without any active controlling of heating or cooling.