Suppression of Flow Boiling Instabilities in Microchannels Using Artificial Reentrant Cavities

Flow boiling instability in parallel microchannel and the ability of artificial reentrant cavities to suppress their occurrence was experimental studied. Experiments were conducted using two types of 226 μm hydraulic diameter parallel microchannel devices: microchannel with reentrant cavities and plain-wall microchannel. Onset of nucleate boiling (ONB), critical heat flux (CHF) condition, onset of flow oscillation (OFO), and local temperature were also obtained and compared. It was found that reentrant cavities on channel walls can assist mitigating the rapid bubble growth instability and postpone the parallel channel and compressible volume instability, which resulted in the delay of CHF.Copyright © 2007 by ASME