Flow boiling phenomena in a single annular flow regime in microchannels (I): Characterization of flow boiling heat transfer

Surface Structure Enhanced Microchannel Flow Boiling

“…In addition to the heating element, we incorporated four thin-film resistance temperature detectors (RTDs), which are commonly used for flow boiling studies [22][23][24]40,41], along the length of the heater to measure the microchannel backside surface temperature at different locations. Specifically, the distances x of RTD1 through RTD4 from the inlet of the microchannel were 0 mm, 1.4 mm, 5.7 mm and 10 mm respectively (Figure 2a).…”

“…To suppress flow instability and to enhance heat transfer, recent studies have focused on incorporating various structures in microchannels, such as inlet restrictors [12][13][14], artificial nucleation sites [14,15], vapor venting membranes [16][17][18], micro pin fins [19][20][21], and nanowire-coated surfaces [22][23][24] integrated into the microchannel.…”

“…In fact, in pool boiling, superhydrophilic micro and nanostructures have demonstrated significantly increased CHF [25][26][27][28][29][30][31] and biphilic patterned surfaces have shown large enhancements in heat transfer coefficients [32,33]. In flow boiling, silicon nanowire-coated channel surfaces have been reported to reduce temperature fluctuations [22], increase the heat transfer coefficient and CHF, and decrease the pressure drop across the microchannels with water as the working fluid [23,24]. The enhancement mechanism was mainly attributed to both increased wettability in delaying CHF and nucleation sites formed by the nanowire bundles to improve the heat transfer coefficient in the nucleate boiling regime.…”

Boiling heat transfer during flow of distilled water in an asymmetrically heated rectangular minichannel

“…Flow boiling heat transfer of water in minichannels and microchannels has been described by various researchers (see, for example, [1][2] and [3][4][5], respectively). Reference [1] investigates the effect of pressure (ranging from 2 to 16 bar) on the flow boiling of water.…”

“…References [3][4] deal with the flow boiling of deionised and degassed water for different mass fluxes in a vertical narrow rectangular microchannel with a hydraulic diameter of d h = 0.48 mm [3] and d h = 1.2 mm [4]. A study of the flow boiling of deionized water in silicon microchannels in a single annular flow boiling regime is presented in [5].…”