Natural convection boiling of water and surfactant solutions having negligible environmental impact in vertical confined space

Natural convection boiling of water and surfactant solutions in a confined space between two vertical plates was studied experimentally in the range of heat flux 19–170 kW/m2. The surfactant used was Alkyl (8–16) Glucoside having negligible environmental impact. The gap size was changed in the range of s = 1–80 mm, the concentration of surfactant solutions was changed in the range of C = 200–600 ppm. Generally, an addition of surfactant leads to an enhancement of heat transfer compared to water boiling at the same gap size. Enhancement of the heat transfer depending on the solution concentration at fixed gap size yields maximum value at the solution concentration close to the critical micelle concentration. The effect of confined space on a bubble dynamic was studied. Temperature field on the heater was determined using the infrared thermography technique. Quasi periodic wall temperature fluctuations were observed in the regime of high heat flux. An increase in the Bond number leads to an increase in the dimensionless frequency of the heated wall temperature fluctuations. The correlation between the dimensionless parameter of heat transfer and the Bond number under condition of quasi periodic boiling was derived and discussed.