LAYERED COMPOSITE HEAT EXCHANGERS – MODELLING OF THERMAL AND STRENGTH PROPERTIES

There are many heat enhancing structures available on the market and already researched, but the application of layered composites for their development has not been completely investigated, especially regarding modelling of the physical phenomena of boiling heat transfer and mechanical properties. The present paper presents a modified model of boiling heat transfer and modelling of the strength properties of composite heat exchangers made of mesh layers. The experimental results (obtained by the authors) of the boiling heat transfer of distilled water and ethanol under atmospheric pressure on copper substrates covered with brass, bronze and copper layers were used for modified model development. It needs to be noted that the problem of modelling the heat transfer of such structures has not been properly addressed to date with many issues in need of clarification. The present paper’s novelty is mainly focused on providing a more reliable equation for heat flux regarding boiling on metal composite mesh layers. It also proposes a calculation procedure for selected strength properties of such structures. The application of the modified boiling heat transfer correlation resulted in almost all the measurement points lying within or close to the ±100% error band, while in the case of the original model none of the experimental points was even close to this error band (the differences reached even about one order of magnitude).