Experimental study on flow boiling characteristics in microchannels with trapezoidal rib walls
Yuting Jia, Dongxiao Zhang, Jann‐Tay Wang, Guodong Xia
Abstract
In this work, a microchannel heat sink with trapezoidal rib walls (TRAM), in which walls are partially made of trapezoidal ribs by MEMS (Microelectrical Mechanical System) technique are put forward. The influences of mass flux, heat flux and exit vapor quality on flow pattern, boiling curving, heat transfer coefficient (HTC), two-phase pressure drop, and wall temperature characteristics of TRAM are investigated and the traditional rectangular microchannel heat sink (RECM) is as the reference. Experiments are carried out using pure acetone liquid with the mass flux from 255 to 843 kg/(m 2 ·s) and heat flux from 10 to 132 W/cm 2 . The results show that the onset of nucleate boiling (ONB) of TRAM increase with the increase of mass flux. The HTC of TRAM is larger than that of RECM whether at low or high heat flux. The pressure drop of TRAM increases more significantly with increasing heat flux and vapor quality. At the same time, the pressure drop of TRAM is lower than that of RECM. The flow instability is more moderate at a larger mass flux and heat flux owing to the more uniform bubble size and bubble distribution.