Experimental study of bubble dynamics in pool boiling heat transfer using saturated water and surfactant solution

In this paper, bubble dynamics in pool boiling heat transfer using saturated water and aqueous Ammonium Chloride (anionic surfactant) solution has been studied experimentally. The concentration of surfactant was taken 2600 ppm (Parts per Million). Single bubble is generated using right angle needle tip of a hypodermic needle as a nucleation site. The bubble dynamics was studied using SONY Cyber-shot DSC-H100 camera operating at 30 frames per second at atmospheric pressure. Bubble growth in saturated water is compared surfactant solution. The result shows that, at low heat flux (q= 235 KW/m²), the bubble diameter, bubble height and bubble volume in surfactant solution approximately similar to that of water. At high heat flux (q= 738 kW/m²), the departure diameter of water bubbles was approximately same. But, in surfactant solution, the departure diameter decreases with increasing heat flux and thereby enhances pool boiling heat transfer coefficient. The enhancement is observed due to surface tension of the aqueous solution. The effect of surfactant on bubble release frequency is also discussed.