Rupture of a Locally Heated Liquid Film Driven by the Shear Stress of Gas and Gravity
The paper focuses on the recent progress that has been achieved by the authors through conducting experiments with locally heated shear-driven and falling liquid films. Rupture of the liquid film was investigated and it was found that scenario of film rupture differs widely for different flow regimes. The critical heat flux is about 10 times higher for a shear driven film than that for a falling liquid film, and reaches 250 W/cm2 in experiments with water at atmospheric pressure. Rupture of a subcooled falling liquid film heated from the substrate is preceded by the formation of steady state film surface deformations. The film spontaneously ruptures at the moment when the film thickness in the thinned region reaches a certain critical minimum independent of both the Reynolds number and the plate inclination angle (gravity force). By means of high speed imaging it is found that the process of rupture involves two stages: 1) abrupt film thinning down to a thin residual film; 2) rupture and dryout of the residual film. As the plate inclination angle is reduced the threshold heat flux required for film rupture weakly decreases, however when the angle becomes negative the threshold heat flux begins to rise dramatically, which is associated with an increase of the stabilizing hydrostatic effect due to the growth of the film thickness.
liquid film narrow channel dry patches critical heat flux critical film thickness thermocapillary effect
D.V.Zaitsev O.A.Kabob
Institute of Thermophysics SB RAS, Novosibirsk, Russi Heat Transfer International Research Institute Institute of Thermophysics SB RAS, Novosibirsk, Russi Heat Transfer International Research Institute
国际会议
西安
英文
286-291
2009-07-11（万方平台首次上网日期，不代表论文的发表时间）