Xanthopoulou, Yiota ; Sielaff, Axel ; Stephan, Peter (2023)
Experimental investigation on the influence of Ethanol/Water mixtures on microstructure surfaces during nucleate boiling.
17th International Heat Transfer Conference. Cape Town, South Africa (14.-18.08.2023)
doi: 10.1615/IHTC17.360-20
Konferenzveröffentlichung, Bibliographie

Kurzbeschreibung (Abstract)

Extensive research has been conducted on nucleate pool boiling over the past few decades, investigating numerous parameters, such as the use of different fluids and boiling surfaces. Despite all these studies, the complex phenomenological interactions between solids and fluids are still poorly understood. There is still a need to study specific combinations of complex fluids and complex surfaces. This experimental study focuses on analyzing the influence of a microstructured surface on boiling phenomena. Here, the microstructured surface consists of copper with striped areas of microneedles alternating with smooth striped areas. This hybrid structure is intended to provide a compromise between good nucleation and bubble growth and good vapor removal. For comparative purposes, a completely smooth copper surface is investigated too. Pure ethanol and a 10% ethanol-water mixture are used as fluids at two different system pressures of 0.5 bar and 1 bar. To analyze the heat transfer coefficient and the critical heat flux, temperatures at the heated surface and in the fluid, as well as heat fluxes, are measured with high resolution. The results with pure ethanol show that the heat transfer coefficient and the critical heat flux are higher when using the hybrid microstructured surface. When using the mixture, the microstructure only favors the heat transfer coefficient but not the critical heat flux density.

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