Condensation on a Downward-facing Horizontal Rippled Surface

1972 ◽  
Vol 94 (3) ◽  
pp. 315-320 ◽  
Author(s):  
Avram Markowitz ◽  
B. B. Mikic ◽  
A. E. Bergles
Keyword(s):  
Experimental Data ◽  
Small Diameter ◽  
Horizontal Cylinder ◽  
Analytical Investigation ◽  
Film Condensation ◽  
Radius Of Curvature ◽  
Condensation Rate ◽  
Projected Area ◽  
Condensate Film ◽  
Constant Radius

An analytical investigation is presented for film condensation on a downward-facing horizontal doubly rippled surface. Small undulations having constant radius of curvature are combined with larger cylindrical grooves designed to aid condensate runoff. A direct expression for the condensate film thickness at the top of an undulation crest, as well as on a small-diameter horizontal cylinder, is derived. An upper-bound expression for the condensation rate on the rippled surface is then obtained which predicts that the condensation rate will be five times the rate attainable on a flat horizontal surface of the same projected area. This analytical expression is compared with experimental data.

A General Correlation for Pool Film Boiling Heat Transfer From a Horizontal Cylinder to Subcooled Liquid: Part 2—Experimental Data for Various Liquids and Its Correlation

1990 ◽  
Vol 112 (2) ◽  
pp. 441-450 ◽  
Author(s):  
A. Sakurai ◽  
M. Shiotsu ◽  
K. Hata
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Analytical Solution ◽  
Boiling Heat Transfer ◽  
Radiation Effects ◽  
Approximate Analytical Solution ◽  
Horizontal Cylinder ◽  
Film Boiling ◽  
System Pressure ◽  
Horizontal Cylinders

Experimental data of pool film boiling heat transfer from horizontal cylinders in various liquids such as water, ethanol, isopropanol, Freon-113, Freon-11, liquid nitrogen, and liquid argon for wide ranges of system pressure, liquid subcooling, surface superheat and cylinder diameter are reported. These experimental data are compared with a rigorous numerical solution and an approximate analytical solution derived from a theoretical model based on laminar boundary layer theory for pool film boiling heat transfer from horizontal cylinders including the effects of liquid subcooling and radiation from the cylinder. A new correlation was developed by slightly modifying the approximate analytical solution to agree better with the experimental data. The values calculated from the correlation agree with the authors’ data within ± 10 percent, and also with other researchers’ data for various liquids including those with large radiation effects, though these other data were obtained mainly under saturated conditions at atmospheric pressure.

Heat Convection from a Horizontal Cylinder Rotating in a Quiescent Fluid

1986 ◽  
Vol 10 (3) ◽  
pp. 141-152
Author(s):  
H.M. Badr ◽  
S.M. Ahmed
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mathematical Model ◽  
Horizontal Cylinder ◽  
Heat Transfer Process ◽  
Two Dimensional ◽  
Two Dimensional Flow ◽  
Boussinesq Fluid ◽  
The Mathematical Model ◽  
Quiescent Fluid

The aim of this work is a theoretical investigation to the problem of heat transfer from an isothermal horizontal cylinder rotating in a quiescent fluid. The study is based on the solution of the conservation equations of mass, momentum and energy for two-dimensional flow of a Boussinesq fluid. The effects of the parameters which influence the heat transfer process namely the Reynolds number and Grashof number are considered while the Prandtl number is held constant. Streamline and isotherm patterns are obtained from the mathematical model and the results are compared with previous experimental data. A satisfactory agreement was found.

Effect of Uniform Suction on Laminar Film Condensation on a Porous Vertical Wall

1970 ◽  
Vol 92 (2) ◽  
pp. 252-256 ◽  
Author(s):  
Ji Wu Yang
Keyword(s):  
Heat Transfer ◽  
Vertical Wall ◽  
Power Series Expansion ◽  
Porous Wall ◽  
Film Condensation ◽  
Condensation Rate ◽  
Suction Velocity ◽  
Uniform Suction ◽  
Laminar Film Condensation ◽  
Prandtl Numbers

The problem of film condensation on a porous wall has been solved by a boundary layer treatment. A dimensionless suction velocity parameter β, which is proportional to the uniform suction velocity vw and 1/4th the power of longitudinal coordinate (x1/4), is defined to characterize the process. The results are restricted to small values of β, as the solutions are given by power series expansion in β. The effects of uniform suction on heat transfer, condensation rate, film thickness, and velocity and temperature profiles are demonstrated through various examples. In general, uniform suction causes a substantial increase of heat transfer and condensation rate, especially at low subcooling and at high Prandtl numbers. The problem involves three governing parameters: subcooling, Prandtl number, and suction velocity. Comparison with the previous work of Jain and Bankoff is discussed.

scholarly journals Dynamic Response of Shear-Flexible Cylindrical Isotropic Shells with Clamped Edges

2006 ◽  
Vol 13 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Zafer I. Sakka ◽  
Jamal A. Abdalla ◽  
H.R.H. Kabir
Keyword(s):  
Free Vibration ◽  
Cylindrical Shells ◽  
Shell Element ◽  
Double Fourier Series ◽  
Analytical Investigation ◽  
Fourier Series Expansion ◽  
Mode Shapes ◽  
Radius Of Curvature ◽  
Bench Mark ◽  
Approximate Methods

It is fundamental to obtain the natural frequencies and the corresponding mode shapes for cylindrical shells in order to determine their response to different dynamic loading. In this paper an analytical investigation to the free vibration response of moderately-thick shear flexible isotropic cylindrical shells with all edges clamped is presented. The Sander’s kinematic relations for moderately thick cylindrical shell panels are utilized to develop the governing partial differential equations in conjunction with the boundary conditions. A recently developed generalized Navier’s approach, based on a boundary continuous double Fourier series expansion, is used as a solution methodology. A parametric study is presented with respect to various thicknesses, length and radius of curvature of the shell panel. The convergence of the solution method is established numerically for various parametric properties. The present results are compared with the results obtained from finite element method using a four-node isoparametric shell element. The results thus presented should serve as bench-mark solutions for future comparisons with numerical and approximate methods for calculation of free vibration parameters of moderately-thick isotropic cylindrical shells.

An Analytical Investigation of Free Convection Heat Transfer to Supercritical Water

1970 ◽  
Vol 92 (3) ◽  
pp. 345-350 ◽  
Author(s):  
E. S. Nowak ◽  
A. K. Konanur
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Free Convection ◽  
Supercritical Water ◽  
Thermophysical Properties ◽  
Convection Heat Transfer ◽  
Analytical Investigation ◽  
Convection Heat ◽  
Free Convection Heat ◽  
Vertical Flat Plate

Heat transfer to supercritical water (at 3400 psia in the pseudocritical region) by stable laminar free convection from an isothermal, vertical flat plate was analytically investigated. The actual variations with temperature of all or some of the thermophysical properties of supercritical water were taken into consideration. Fair agreement was found between the analytical values of this paper and existing experimental data.

Modeling of Interfacial Shear for Gas Liquid Flows in Annular Film Condensation

1996 ◽  
Vol 63 (2) ◽  
pp. 529-538 ◽  
Author(s):  
A. Narain
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Internal Flow ◽  
Admissible Solution ◽  
Interfacial Shear ◽  
Film Condensation ◽  
Vapor Flow ◽  
Pressure Drops ◽  
Transfer Rates ◽  
Stability Type

Internal flow of pure vapor experiencing film condensation on the walls of a straight horizontal duct is studied. The commonly occurring annular case of turbulent (or laminar) vapor flow in the core and laminar flow of the liquid condensate—with or without waves on the interface—is emphasized. We present a new methodology which models interfacial shear with the help of theory, computations, and reliable experimental data on heat transfer rates. The theory—at the point of onset of condensation—deals with issues of asymptotic form of interfacial shear, nonuniqueness of solutions, and selection of the physically admissible solution by a stability type criteria. Other details of the flow are predicted with the help of the proposed modeling approach. These predictions are shown to be in agreement with relevant experimental data. The trends for film thickness, heat transfer rates, and pressure drops are also made available in the form of power-law correlations.

scholarly journals Experimental and theoretical study of dryout in annular flow in small diameter channels

2011 ◽  
Vol 32 (1) ◽  
pp. 89-108 ◽  
Author(s):  
Dariusz Mikielewicz ◽  
Michał Gliński ◽  
Jan Wajs
Keyword(s):  
Experimental Data ◽  
Liquid Film ◽  
Annular Flow ◽  
Theoretical Study ◽  
Small Diameter ◽  
Infrared Camera ◽  
Equation Model ◽  
Internal Diameter ◽  
Two Phase ◽  
Liquid Film Dryout

Experimental and theoretical study of dryout in annular flow in small diameter channels In the paper the experimental analysis of dryout in small diameter channels is presented. The investigations were carried out in vertical pipes of internal diameter equal to 1.15 mm and 2.3 mm. Low-boiling point fluids such as SES36 and R123 were examined. The modern experimental techniques were applied to record liquid film dryout on the wall, among the others the infrared camera. On the basis of experimental data an empirical correlation for predictions of critical heat flux was proposed. It shows a good agreement with experimental data within the error band of 30%. Additionally, a unique approach to liquid film dryout modeling in annular flow was presented. It led to the development of the three-equation model based on consideration of liquid mass balance in the film, a two-phase mixture in the core and gas. The results of experimental validation of the model exhibit improvement in comparison to other models from literature.

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