THE CALCULATE OF PHYSICAL PROPERTIES AND STUDY ON HEAT TRANSFER CHARACTERISTICS IN MICRO CHANNEL

Microscale high efficiency heat exchanger has the character of compact structure,low thermal resistance and high heat transfer coefficient. The density,saturated pressure,surface tension and viscosity of the refrigerant mixed with A and B were calculated and curve fitting of physical properties to temperature with the standard deviation under 1 percent were established. The heat transfer characteristics in a rectangle micro channel with the size of 1.1 mm/1.2 mm at the inlet temperature of -45,20 and 60℃ the external heat flux density of 400 W is studied,the different working condition has the same effective heat exchange heat flux density while the average heat transfer coefficient grows with the inlet temperature.