In order to examine the combined effects of surface roughness and concentration on pool boiling of nanoparticle suspensions

an experimental study on quenching processes of aqueous suspensions with carbon nanotubes(0.1% and 0.5%)was conducted using nickel-plated copper spheres with surface roughness of Ra0.5 and Ra12.5.Quenching curves were acquired directly and boiling curves during the quenching processes were calculated based on a lumped capacitance model.It is shown that increase in both concentration of suspensions and surface roughness expedites quenching speed and enhances critical heat flux.Increase in surface roughness decreases the time duration of nucleate boiling and less film boiling time is primarily due to increased concentration.The combined effects of surface roughness and concentration suggest that quenching objects are utilized with rough surfaces in nanoparticle suspensions of relatively high concentration so as to significantly shorten the quenching time for engineering applications.