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Heat Transfer and Pressure Drop in a Plate-Type Evaporator

Sven Wellsandt (Institutionen för kemiteknik och miljövetenskap, Värmeteknik och maskinlära) ; Lennart Vamling (Institutionen för kemiteknik och miljövetenskap, Värmeteknik och maskinlära)
International Journal of Refrigeration Vol. 26 (2003), p. 180-188.
[Artikel, refereegranskad vetenskaplig]

A plate-type evaporator, working with natural refrigerant circulation, has been investigated both experimentally and theoretically. Motivated by the phase-out of ozone-depleting substances, HCFC22 was compared to HFC134a and two zeotropic refrigerant mixtures. The effect of different separator liquid levels, i.e. refrigerant flows, and its influence on heat transfer was also studied. The investigated plate-type evaporator consists of thirteen vertical flow channels and its size is 3.0 m x 0.5 m. The heat source for the evaporator is a falling water film on the outside of the plate. Experimental studies have been carried out using a test facility that enabled detailed measurements of heat transfer and pressure drop. Experiments were compared to results from a calculation method that simultaneously calculates heat transfer and pressure drop in a variable number of steps along the evaporator. The calculation method is based on a pressure drop correlation proposed by the VDI-Warmeatlas and a heat transfer correlation for vertical tubes proposed by Steiner and Taborek. For different evaporator duties, heat transfer was over predicted by 12% for pure fluids by 15% for mixtures. Calculated pressure drops were well within +/-5% of the measured values. Changes in heat transfer due to different flows were closely predicted by the proposed calculation method.

Nyckelord: Heat transfer; Mass transfer; Heat exchanger; Plate exchanger; Heat transfer coefficient; Pressure drop;

Denna post skapades 2007-06-27. Senast ändrad 2015-02-11.
CPL Pubid: 43272


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Institutioner (Chalmers)

Institutionen för kemiteknik och miljövetenskap, Värmeteknik och maskinlära (2002-2004)



Chalmers infrastruktur