Explosive Vaporization of Water and Isopropyl Alcohol on a Flat Microheater

Abstract

The MEMS control systems, such as ink jet printers, optical switches and valves, use the explosive vaporization of metastable liquid for the rapid phase change. The initial stage of explosive vaporization of water, isopropyl alcohol and ethanol has been studied experimentally on the surface of a thin-film microheater, covered with the submicron silicon-carbide layer. In experiments, the multilayer thin-film resistor of the Think Jet printhead with 100 × 110 μm2 surface area was used. Applying the optical method, we investigated the patterns of the liquid–vapor phase transition under pulse heating and obtained the characteristics of nucleation at the rate of temperature growth of up to 800 MK/s. Pulsed laser illumination was applied for the high-speed photography of liquid vaporization. Data for the vapor-covered surface area vs. time depending on the supplied heat flux and the heating time are reported. The theoretical model of explosive vaporization on a flat heater has been developed and numerical simulations have been performed for water and isopropyl alcohol nucleation on the multi-layer microheater. Comparison of calculation results with experimental data is discussed in this paper.