Publikacje

Abstract:

The aim of the paper is to estimate effect of the heating surface enhancement on FC-72 flow boiling
heat transfer for a vertical minichannel 1.7 mm deep, 24 mm wide and 360 mm long. Two types of enhanced
heating surfaces were used: one with minicavities distributed unevenly, and the other with capillary metal
fibrous structure. It was to measure temperature field on the plain side of the heating surface by means of the
infrared thermography and to observe the two-phase flow patterns on the enhanced foil side. The paper
analyses mainly the impact of the microstructured heating surface on the heat transfer coefficient. The results
are presented as heat transfer coefficient dependences on the distance along the minichannel length. The data
obtained using two types of enhanced heating surfaces in experiments was compared with the data when
smooth foil as the heating surface was used. The highest local values of heat transfer coefficient were obtained
using enhanced foil with minicavities - in comparison to other cases. Local values of heat transfer coefficient
received for capillary fibrous structure were the lowest, even compared with data obtained for smooth foil.
Probably this porous structure caused local flow disturbances.

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Effect of the heating surface enhancement on the heat transfer coefficient for a vertical minichannel