Visualization of Pool Boiling From Plain and Enhanced Structures

Abstract

A visualization study of pool boiling at atmospheric pressure from plain and enhanced structures was conducted with PF 5060 as working fluid. The single layer enhanced structures were fabricated in copper and were 1 mm thick. The parameters investigated in the present study are heat flux, width of microchannels and overall structure width. A monochrome CCD camera with attached magnifying lens served as the main tool for observation of the boiling process from the structures. The nucleate boiling regime for a plain surface is usually divided into two sub-regimes: the isolated bubbles regime and the coalesced bubbles regime. For enhanced structures, the increase in geometric complexity leads to different flow regimes that may establish under different heat fluxes. This study evaluates these regimes using movies and still photographs. A comparison with the plain case is made and the differences highlighted.

Some investigations on the enhancement of boiling heat transfer from planer surface embedded with continuous open tunnels

“…Tunnel type embedded surfaces also became popular as all the vapor traps for such surfaces are interconnected which helps to avoid liquid dry out. Ghiu et al [15] performed a visualization study of pool boiling from 0.090 mm  0.285 mm channel structures. Ramaswamy et al [16] studied bubble growth using high speed photography (1500 frames/s) on microporous structures immersed in a pool of dielectric coolant (FC-72).…”