TY - JOUR

T1 - Influence of artificial disturbances on characteristics of the heated liquid film

AU - Chinnov, Evgeny A.

AU - Abdurakipov, Sergey S.

PY - 2017/10

Y1 - 2017/10

N2 - The characteristics of a water film flowing down a vertical plate with a heater at high Reynolds numbers (Re = 300 and 500) with and without artificial disturbances with the “most dangerous” wavelength have been studied experimentally. The field of film thickness at different values of heat flux has been measured using the fluorescent method. The temperature field on the liquid film surface was registered by the IR scanner. Artificial disturbances with the “most dangerous” wavelength decrease a distance between the rivulets and transverse deformation of liquid film. The temperature gradients and shear thermocapillary stresses on the film surface become smaller. Artificial disturbances with the “most dangerous” wavelength at high heat fluxes cause an increase in amplitude, spectral energy and integral energy of temperature pulsations per a time unit as well as expansion of the frequency range of temperature pulsations in-between the rivulets at the bottom of the heater. An increase in wave amplitude and velocity is observed in the interrivulet areas. An increase in wave amplitudes, velocities, and average integral pulsations of temperature per a time unit and frequency range expansion in the bottom part of the heater under the action of disturbances can enhance heat transfer and improve film resistance to breakdown.

AB - The characteristics of a water film flowing down a vertical plate with a heater at high Reynolds numbers (Re = 300 and 500) with and without artificial disturbances with the “most dangerous” wavelength have been studied experimentally. The field of film thickness at different values of heat flux has been measured using the fluorescent method. The temperature field on the liquid film surface was registered by the IR scanner. Artificial disturbances with the “most dangerous” wavelength decrease a distance between the rivulets and transverse deformation of liquid film. The temperature gradients and shear thermocapillary stresses on the film surface become smaller. Artificial disturbances with the “most dangerous” wavelength at high heat fluxes cause an increase in amplitude, spectral energy and integral energy of temperature pulsations per a time unit as well as expansion of the frequency range of temperature pulsations in-between the rivulets at the bottom of the heater. An increase in wave amplitude and velocity is observed in the interrivulet areas. An increase in wave amplitudes, velocities, and average integral pulsations of temperature per a time unit and frequency range expansion in the bottom part of the heater under the action of disturbances can enhance heat transfer and improve film resistance to breakdown.

KW - Artificial disturbances

KW - Falling liquid films

KW - High Reynolds numbers

KW - Waves and structures

KW - Wavy and thermocapillary effects

KW - THERMAL ENTRY LENGTH

KW - WAVE CHARACTERISTICS

KW - 3-DIMENSIONAL WAVES

KW - INSTABILITIES

KW - HIGH REYNOLDS-NUMBERS

KW - FLUORESCENCE

KW - VELOCIMETRY

KW - FALLING FILM

KW - SURFACE

KW - DYNAMICS

UR - http://www.scopus.com/inward/record.url?scp=85019846420&partnerID=8YFLogxK

U2 - 10.1016/j.ijheatmasstransfer.2017.05.064

DO - 10.1016/j.ijheatmasstransfer.2017.05.064

M3 - Article

AN - SCOPUS:85019846420

VL - 113

SP - 129

EP - 140

JO - International Journal of Heat and Mass Transfer

JF - International Journal of Heat and Mass Transfer

SN - 0017-9310

ER -