I have a lab for heat transfer and i need the (comment) of the effect of flow arrangements on the overall efficiency of plate heat exchager i need help .
The channel formed by two adjacent plates is the key to the plate heat exchanger's high efficiency. The hot and cold fluids are distributed through alternate channels in a counter-current arrangement. This counter-current flow provides for maximum thermal efficiency. The flow pattern induces turbulence at very low Reynolds numbers, which also contributes to high heat transfer rates. Units are custom selected to effectively optimize the available pressure drop. The fluid shear stresses in a plate exchanger are much higher than those of a tubular exchanger. This tends to keep the channels in a plate exchanger much cleaner. For clean services, the normal practice is to provide units designed for 100% of the surface area required. For fluids that foul, plate exchangers can be provided with 5-10% excess area. Plate heat exchangers are well suited for applications that require close temperature approaches. (The approach temperature is defined as the hot fluid outlet temperature minus the cold fluid inlet temperature.) Units can achieve temperature approaches as close as 2 degrees F.
