Investigations of the spreading of falling liquid films in inclined tubes

Theoretical and Experimental Investigation of the Minimum Wetting Rate of a Falling Water Film on the Vertical Grooved Plate

“…Nowadays, to ensure the integration and stability of the falling film, the vertical grooved plate has attracted more and more attention. Researchers found that the falling liquid film on the grooved surface is more stable and has a higher heat transfer coefficient and a higher threshold heat flux than that on the smooth surface. − Eichinger et al experimentally investigated the film spreading inside a smooth tube and spiral-grooved tubes with different inclination angles. The results revealed that the grooved tube had higher inside surface wetting rates in the inclined and partly evaporation conditions.…”

Three-Dimensional Mathematical Model of the Liquid Film Downflow on a Vertical Surface

“…As mentioned above, the liquid film flow is considered not only on vertical surfaces but also inside channels of various configurations [19][20][21][22][23][24][25]. The paper [19] describes the influence of bubble approach velocities on the liquid film drainage process under constant conditions for plane parallel immobile surfaces by the Stefan-Reynolds model.…”

“…For example, these effects are essential for oil recovery from tar sands. The authors of study [20] carried out the experimental studies of falling liquid films in internally structured tubes with intermediate and steep spiral grooves. Water and propane were used for forming the liquid film.…”

“…Additionally, equations for determining the averaged film thickness, the averaged velocity vectors over the film thickness, the longitudinal and vertical velocity components, and the initial angle of streamline deviation from the vertical axis were analytically obtained.Energies 2020, 13, 1938 2 of 15 the fluid film movement, heat and mass transfer in column equipment, the separation of gas-liquid mixtures, and fluid flow in heat exchangers. Scientists for the above purpose have investigated the heat and mass transfer processes occurring in microchannels [3][4][5][6] and free and induced liquid film flow over different surfaces [7][8][9][10][11][12][13][14][15][16][17][18] and inside of different channels [19][20][21][22][23][24][25]. This flow occurs due to the influence of various forces, which determine the film formation or destruction, and the inclination angle of the surface.…”

“…where R-the error function-∆Q u = Q u1 − Q u0 is the difference of the liquid flow rates in a vertical direction, and ∆Q w = Q w1 − Q w0 is the difference of the liquid flow rates in the horizontal direction. In this case, the differences of the liquid flow rates are equal in module value according to Equation (20):…”