Flow pattern analysis of flow boiling inside a 0.48 mm microtube

On flow boiling of R-1270 in a small horizontal tube: Flow patterns and heat transfer

“…TS kW/m 2 for G = 240 kg/(m 2 s) e ≈ − x o TS ( ) 0.5. This flow pattern has been observed by other studies in small channels with other working fluids, including R134a and R245fa ( [31]), FC-72 ( [32]), R-290 ( [33]), R-600a ( [34]). In the wavy-annular regime, an increase of the heat flux causes the decrease of the thickness of liquid layer and, possibly, the reaching of (smooth) annular flow. )…”

Experimental investigation on bubble sliding during subcooled flow boiling in microchannel

“…While with the increase of heat flux, nucleated bubbles were observed to confine in the microgap without slippage. Celata et al [30] investigated the flow pattern of flow boiling inside a 0.48 mm microtube, they observed that after detachment some bubbles slid attached to the heated wall and increased their volume slightly, while others just flow toward the channel exit without showing any volume change. It can be easily noted that the existing literatures on sliding bubble in microchannel mainly focused on observing the bubble growth state during sliding process, while the bubble sliding behaviors were not been paid much attention.…”