Bubble growth and heat-transfer mechanisms in the forced convection boiling of water containing a surface active agent

An experimental study on bubble rise path after the departure from a nucleation site in vertical upflow boiling

“…[12], typical bubbles slid along the heating surface after the departure and were not detached from the wall in vertical upflow boiling. Several other observations might support this result [1,3]. Prodanovic et al [9] conducted the bubble visualization study in subcooled flow boiling of water in a vertical annulus and reported that bubbles usually slid along the vertical heater with small number of exceptions when the heat flux is sufficiently low but they typically traveled into the liquid core after the sliding for a couple of bubble diameters when the heat flux was increased.…”

“…In these experiments, the important bubble parameters including the size, shape, growth and collapse rates, population, frequency and trajectory were measured in varied conditions of working fluid, system pressure, liquid subcooling, applied heat flux and inlet velocity. The influences of flow direction [12], existence of surface active agent [3] and gravity level [10] were also investigated.…”

“…Sufficient understanding of the complex interaction between the vapor bubbles and turbulent liquid flow is hence important to develop reliable 0894 prediction methods for the heat transfer rate in flow boiling. Thus, extensive visual observations of vapor bubbles in vertical upflow boiling were conducted in subcooled conditions [1][2][3][4][5][6][7][8][9] and also in saturated or slightly subcooled conditions [10][11][12]. In these experiments, the important bubble parameters including the size, shape, growth and collapse rates, population, frequency and trajectory were measured in varied conditions of working fluid, system pressure, liquid subcooling, applied heat flux and inlet velocity.…”

Numerical study on the characteristics of natural supercavitation by planar symmetric wedge-shaped cavitators for rotational supercavitating evaporator

“…The increase of operating temperature of the brine can lower the rotational speed of blades (and hence the mechanical energy consumption of RSCE) for formation of supercavity, due to the fact that the saturated vapor pressure increases with the increase of temperature. The introduction of viscoelasticity is to further optimize the performance of RSCE, which utilizes the particular characteristics of viscoelastic aqueous solutions of some certain surfactant: turbulent drag reduction [18][19][20][21][22], reduction of surface tension [23,24] and promoting vaporization including enhancement of boiling heat transfer [25][26][27][28] and promotion of supercavitation [29,30]. For the first step, i.e., blade shape improvement, numerical simulations on supercavitating flows around two-dimensional planar symmetric wedge-shaped cavitators with different wedge angles are performed in this paper.…”

Multiscale Modeling of Multiphase Fluid Flow

“…Additives have long been recognized and studied for the purposes of enhancing the boiling heat transfer [35][36][37][38] and heat transfer with surfactant additives in pool boiling is the topic of active research in thermal management [39][40][41][42][43][44][45], spray-cooling [46], micro and nano-fluidics [47][48][49][50][51]. Additives can enhance or diminish the effectiveness of boiling heat transfer depending on the chemistry or concentration of the additives [35,37,38,44,[48][49][50][52][53][54][55][56]. On a macroscopic level, solution additives contribute to dynamic surface tension [36,40,52,57] and modify the surface wettability [58].…”