Abstract: The paper deals with determination of boiling heat transfer coefficient in research using the test section with two parallel vertical minichannels, each of 1 mm depth. The heating element for fluorinert FC-72 in minichannels is the thin foil enhanced on the side contacting fluid. It is possible to observe the channel surfaces through glass panes:
1) of the first minichannel allows observing foil temperature changes on the plain side due to liquid crystal thermography, 2) of the second minichannel enables detecting outer glass temperature changes due to infrared thermography. The next glass pane allows conducting two-phase flow visualization on the enhanced foil side. The objective is to evaluate the one- and two-dimensional heat transfer models for calculating the heat transfer coefficient at the foil-fluid interface. In 2D method the foil temperature distribution on the enhanced side contacting fluid is obtained by solving the inverse heat conduction problem. The auxiliary direct problem in the glass pane is considered. The governing equations are solved by means of the finite element method combined with Trefftz functions as shape functions (FEMT). Unknown coefficients of linear combination of shape functions are calculated from the minimization of the functional. Temperature measurement points were located in boundary nodes of elements. The results presented as liquid crystal thermographic images, infrared thermographs, local surface temperatures and heat transfer coefficient as a function of the distance from the minichannel inlet, calculated using the one- and two-dimensional models, are analyzed.
