Surface characteristics such as surface roughness and surface wettability are the most important factors that affect heat transfer coefficient (HTC) and critical heat flux (CHF) in pool boiling. Effect of surface characteristics on pool boiling heat t...
Surface characteristics such as surface roughness and surface wettability are the most important factors that affect heat transfer coefficient (HTC) and critical heat flux (CHF) in pool boiling. Effect of surface characteristics on pool boiling heat transfer of water was investigated using various surfaces having different roughness and different wettability. Surface roughness (R<SUB>a</SUB>) on the copper surfaces having moderate wettability (θ = 65°) was varied from 0.041 μm to 2.36 μm. It is verified that both HTC and CHF increase with increasing surface roughness. Three surfaces having similar surface roughness (R<SUB>a</SUB> ~ 0.11 μm) and different contact angles of 12° (superhydrophilic), 65° (moderate), and 122° (hydrophobic) were examined. While HTC increases with contact angle increase at low heat flux, CHF on the hydrophobic surface was merely 55 kW/m², which is over 20 times smaller than those on hydrophilic surfaces.