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Computational and experimental analysis of the flow characteristics in plate heat exchangers

Although the plate heat exchangers (PHEs) have been widely used in past decades, the complex flow mechanisms in corrugated chevron channels are still subject of numerical and experimental research in order to better understand influence of geometry and flow characteristics on their thermal-hydraulic performances, so as they can be further improved and optimized for a particular application. The most of studies are focused on a single cell when analyzing heat transfer and pressure drop, while the other studies dealing with the whole channel examine the effects of flow distribution on the overall heat transfer coefficient. This paper presents results from the experimentally verified numerical study on the flow in two corrugated chevron channels of PHEs with different chevron angles. 3D CFD numerical simulations are performed under the laminar, transient and fully turbulent flow conditions. The present model allows for examination of the developing flow at the entrance in the chevron part of channel to the fully developed flow in the main parts of channel. A suitability of different laminar and turbulence models for simulations in PHE channels is investigated as well. A relevancy of different methods for determining Nu number and friction factor from the simulation results is discussed. The computed flow patterns are compared with the visualization tests proving co-existence of flow substreams and prevailing impact of the chevron angle on their relative size. Distribution of the heat flux within the channel corrugations is discussed accordingly. The simulated thermalhydraulic characteristics are expressed in terms of the heat flux, Nu number, pressure drop per unit area and friction factor. The computed values are in a relatively good agreement with the present experiments as well as with those from the literature.

plate heat exchangers, CFD numerical simulation, measurements, heat transfer, pressure drop

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