scholarly journals Автомодельность в задаче о ламинарном пленочном кипении на вертикальной поверхности, погруженной в большой объем жидкости

2021 ◽  
Vol 91 (3) ◽  
pp. 402
Author(s):  
В.Б. Хабенский ◽  
А.А. Сулацкий
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Radiative Heat ◽  
Heated Surface ◽  
Vertical Surface ◽  
Film Boiling ◽  
Saturated Liquid ◽  
Self Similarity ◽  
Continuous Transition ◽  
Subcooled Liquid

Two expressions for the Nusselt criterion have been formulated by applying self-similarity methods to the laminar free-convection film boiling on a vertical surface having the finite length, which is submerged into the large volume of arbitrary subcooled liquid. The expressions apply Nusselt criterion to the conditions of continuous transition from film boiling in saturated liquid to the strongly subcooled liquid in order to determine heat transfer between the heated surface and interphase boundary, and heat transfer from this boundary into the volume of liquid; the accompanying radiative heat transfer is taken into account. The hierarchy of different self-similarities is presented.

The Effect of Subcooled Liquid on Laminar Film Boiling

1962 ◽  
Vol 84 (2) ◽  
pp. 149-155 ◽  
Author(s):  
E. M. Sparrow ◽  
R. D. Cess
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Transfer Problem ◽  
Film Boiling ◽  
Physical Parameters ◽  
Two Phase ◽  
Fixed Temperature ◽  
Subcooled Liquid ◽  
Flow And Heat Transfer ◽  
Parameter Ranges

Heat-transfer results for film boiling in the presence of a subcooled liquid have been determined analytically for the case of the isothermal vertical plate. The two-phase flow and heat-transfer problem which arises has been formulated exactly within the framework of boundary-layer theory, and free convection within the liquid has been accounted for. At a fixed temperature difference between surface and saturation, the effect of subcooling is to increase the heat transfer from the plate surface, with the magnitude of the increase being controlled by five physical parameters. Graphical presentation of the heat-transfer results is made for parametric values which correspond to water, but this information may be applied to other fluids having similar parameter ranges. For large subcooling, the heat transfer is essentially equal to that for pure free convection (no boiling), and the limits for this condition are given.

Film Boiling Heat Transfer on an Isothermal Vertical Surface

1985 ◽  
Vol 107 (4) ◽  
pp. 764-771 ◽  
Author(s):  
T. D. Bui ◽  
V. K. Dhir
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Large Scale ◽  
Heated Surface ◽  
Vertical Surface ◽  
Film Boiling ◽  
Small Scale ◽  
Vapor Film ◽  
Interfacial Wave ◽  
Transfer Coefficients

Natural convection film boiling heat transfer of saturated liquids on an isothermal vertical surface is investigated both experimentally and theoretically. Local heat transfer coefficients are obtained at steady-state conditions on a 6.3-cm-wide and 10.3-cm-high heated surface which was machined from a large block of copper. Effectively isothermal surface conditions are achieved even for wall superheats up to 450 K. Experiments conducted with water at 1 atm pressure show that predictions from existing theoretical models are inadequate and a detailed consideration of the liquid-vapor interface behavior is required. Still and motion pictures of the vapor film are taken and data on vapor film thickness, interfacial wave behavior, and bubble detachment characteristics are obtained to build an analytical model for predicting film boiling heat transfer. This time-dependent model based on laminar flow in the film incorporates the effects of both large-scale and small-scale waves. Results from analysis are compared with experimental data.

Pseudoboiling Heat Transfer to Supercritical Pressure Water in Smooth and Ribbed Tubes

1970 ◽  
Vol 92 (3) ◽  
pp. 490-497 ◽  
Author(s):  
J. W. Ackerman
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heated Surface ◽  
Supercritical Pressure ◽  
Heat Fluxes ◽  
Film Boiling ◽  
Fluid Temperature ◽  
Bulk Fluid ◽  
Pressure Water ◽  
Supercritical Pressure Water

Investigations of heat transfer to supercritical pressure fluids have been going on for some time, and correlations have been developed for both free and forced-convection conditions. In these investigations, unpredictable heat transfer performance has sometimes been observed when the pseudocritical temperature of the fluid is between the temperature of the bulk fluid and that of the heated surface. The unusual performance has been attributed to many causes, but one for which more evidence is being collected is that of a pseudofilm-boiling process similar to film boiling which occurs at subcritical pressures. This paper, which is an extension of work reported earlier on forced-convection heat transfer to supercritical pressure water, presents experimental evidence which suggests that a pseudofilm-boiling phenomenon can occur in smooth-bore tubes. During the period from 1963–1966, tubes with ID’s from 0.37 to 0.96 in. were tested at pressures from 3300–6000 psia and at heat fluxes and mass velocities in the range of interest in steam-generator design. The effects of heat flux, mass velocity, tube diameter, pressure, and bulk fluid temperature on both the occurrence and characteristics of pseudofilm boiling are discussed. Results of a second series of tests conducted in 1967, which show that ribbed tubes suppress pseudofilm boiling at supercritical pressure much like they do film boiling at subcritical pressures, are also discussed.

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