Experimental Research on the Effect of 2‐Ethylhexanol on Water Boiling Heat Transfer at Subatmospheric Pressure

Abstract

The addition of small amounts of surfactant to water can enhance boiling heat transfer substantially. In this experiment, 2‐ethylhexanol is used as the surfactant, and the critical micelle concentration (CMC) of the 2‐ethylhexanol aqueous solution is determined to be 1000 mg/L. The boiling heat transfer coefficients of the solutions in different concentrations on a horizontal copper rod surface at subatmospheric pressures (1.8 kPa to 3.3 kPa) are calculated according to the experiment results. The results indicate the following: when the concentration is 500 mg/L (lower than the CMC), the boiling heat transfer can be enhanced by up to 22%; when the concentration is 1000 mg/L (equal to the CMC), enhancement is up to about 60%; when the concentration is 2000 mg/L (two times the CMC), boiling heat transfer is diminished by about 60%. To a certain extent, this experiment will guide the enhancement of evaporator heat transfer in water vapor compression refrigeration and heat pump systems.