Response of a microheater – solution system with a lower critical solution temperature under a powerful local heat impact. Experimental methodology

The paper describes a methodology for the experimental study of a powerful heat release in a microsized probe immersed in a two-component solution with a lower critical solution temperature. Experimental data on overheating relative to the liquid - liquid spinodal and thermal impact on the stability of the system for a water – PPG-425 solution are presented. The following conclusion is made for a solution whose near-critical mass fraction of PPG-425 is 30%: despite the high density of the heat flux through the heater surface (9.2–13.7 W/m$^2$), its temperature stabilizes at a value exceeding the equilibrium temperature of the liquid – liquid system by approximately 150 K. It is shown that the heat exchange process is stable against changes in the heating parameters: the nature of heat transfer by the solution remains the same. It is revealed that the heat transfer coefficient is several times greater than the corresponding value obtained for water.