Convective boiling in mini- and microchannels

Phase change heat transfer Flow boiling

Figure 1 - Flow configurations in a vertical evaporator tube, according to Collier [17].

Figure 2 - Influence of flow density on flow patterns in a vertical evaporator tube, according to Hewitt and Roberts [32].

Figure 3 - Flow configurations in a horizontal evaporator tube

Figure 4 - Hewitt and Roberts [31] flow pattern map for upward two-phase flow

Figure 5 - Flow map in a horizontal tube for Taitel and Dukler boiling, after Hewitt and Roberts [32] and Carey [9].

Figure 6 - Flow chart of Wojtan et al [81] for boiling in a horizontal tube for R1234yf

Figure 7 - Balance of forces on a two-phase fluid element

Figure 8 - Evolution of fluid and wall temperatures during undersaturated boiling in a vertical tube, from Kandlikar et al. [40].

Figure 9 - Flux density as a function of wall temperature for undersaturated boiling

Figure 10 - Graphical representation of the Shah correlation [66].

Figure 11 - Appearance of critical flow as a function of boiling regime for an imposed flow condition

Figure 12 - Two types of condition for the appearance of critical flow

Figure 13 - Inverted annular flow in convective boiling, after Carey [9]

Figure 14 - Schematic phase distribution in horizontal intratubular flow

Figure 15 - Intratubular flow geometry

Figure 16 - Equivalent configuration for stratified flow regime

Figure 17 - Evolution of the critical flux of a binary mixture as a function of the mole fraction of the liquid, according to Carey [9].

Figure 18 - Transition diameter as a function of reduced pressure for CO2

Figure 19 - Microchannel flow configuration (after Brutin [17])

Figure 20 - Flow map by Revellin and Thome [61] for a phase-change flow of R1234yf

Figure 21 - Schematic diagram of the evolution of the heat transfer coefficient as a function of vapour titre, mass velocity, flux density, saturation temperature and diameter [75].