The Influence of Turbulence on Subcooled Nucleate Pool Boiling

Experiments are performed to study the influence of turbulence (root-mean-square velocity, u(rms) = 0 m/s, 0.013 m/s, 0.026 m/s and 0.038 m/s) on nucleate boiling heat transfer using thin nichrome wires within dodecane layer. Nucleate boiling curves under each turbulent condition are analyzed with corresponding bubble behaviors on the wire. Overall, the heat transfer is enhanced with the increase of turbulence, which is supported by measurements and analysis of bubble departure frequency (BDF), critical heat flux (CHF), and bubble departure size. BDF increases with turbulence strength, while bubble departure size decreases. CHF is increased by 6%. Turbulence also alters the bubble behaviors: sweeping stage, bouncing and merging stage, hanging stage, and film boiling stage show unique bubble behaviors influencing the heat transfer characteristics. (C) 2020 Elsevier Ltd. All rights reserved.