Heat transfer performance and bubble-particle interaction dynamics in particle-laden pool boiling

Adding particles to fluids to enhance boiling heat transfer is promising, with particle size critically influencing boiling behavior. This study experimentally investigates boiling heat transfer and bubble-particle dynamics in particle-laden fluids, emphasizing the effects of aluminum particle size. Boiling curves were recorded, and the dynamics of particle-bubble interactions were captured. Particle and gas-liquid flow patterns were categorized, and the impact of particle-bubble interactions on heat transfer was analyzed. The results indicate that when superheat (Delta T) < 14 K, boiling performance relates positively to particle size. When Delta T exceeds 14 K, it's negative. At low superheat, particles deposit on the heated surface, promoting bubble nucleation and growth in corners. Larger particles provide a greater contact area, promoting bubble growth. Bubbles preferentially detach from the gaps between particles, and larger sizes facilitate this process. As the superheat increases, bubbles begin to merge, forming columns or vapor mass. Smaller particles (1-2 mm) adhere to bubbles, ascending with them in a fluidized state, while larger particles (3-4 mm) resist bubble displacement, leading to bubble/vapor film accumulation on the heated surface, particle suspension, and heat transfer deterioration. Particle bouncing enhances bubble nucleate and growth. Simulation shows particle settling affects local pressure to promotes this process.