An Experimental Investigation of the Natural Convection of a Heat Generating Fluid within a Closed Vertical Cylinder

1970 ◽  
Vol 12 (5) ◽  
pp. 354-363 ◽  
Author(s):  
W. Murgatroyd ◽  
A. Watson
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Experimental Investigation ◽  
Natural Convection ◽  
Theoretical Model ◽  
Vertical Cylinder ◽  
Thermal Boundary Condition ◽  
Cylinder Wall ◽  
Uniform Temperature ◽  
Temperature Distributions

Experimental results are presented of the velocity and temperature distributions within a heat-generating fluid contained in a vertical closed cylinder, for the case in which the outer surface of the cylinder wall is maintained at a uniform temperature. Previous experimental data are compared and an earlier theoretical model for a different thermal boundary condition is reinterpreted for the present case.

An experimental investigation of natural convection in a horizontal cylinder

1970 ◽  
Vol 44 (3) ◽  
pp. 545-561 ◽  
Author(s):  
Irving H. Brooks ◽  
Simon Ostrach
Keyword(s):  
Boundary Condition ◽  
Experimental Investigation ◽  
Steady State ◽  
Natural Convection ◽  
Initial Conditions ◽  
Horizontal Cylinder ◽  
Thermal Boundary Condition ◽  
Cylinder Wall ◽  
Horizontal Diameter ◽  
High Prandtl Number

This work deals with an experimental investigation of natural convection inside a horizontal cylinder. The fluid, geometry, and thermal boundary condition were chosen so as to have a high Prandtl number and unit-order Grashof number.The thermal boundary condition was established by imposing temperatures at two points, 180° apart, on the circumference of the cylinder. The resulting boundary condition for the full 360° was found experimentally and is presented. The apparatus was constructed so that the entire cylinder could be rotated in order to introduce an arbitrary heating angle into the boundary condition.Temperature profiles and streamline patterns were observed at steady state for various values of this heating angle and for various initial conditions. For some cases, velocity profiles were also plotted. It was found that the interior ‘core’ of fluid was thermally stratified when the diameter containing the two imposed temperatures was horizontal. The flow occurred primarily in the region close to the cylinder wall. The cylinder was rotated so that the diameter containing the two imposed temperatures made an angle with the horizontal. The hotter of the imposed temperatures was always below the horizontal diameter of the cylinder. As this angle of rotation increased, it was found that the velocities encountered in the fluid increased and the degree of thermal stratification in the core region decreased. It was also found that the steady-state results were identical for the different initial conditions imposed. The results of this study are compared with previous work, both analytic and experimental.

An Experimental Investigation of Natural Convection With Vertical Cylinders in Mercury

1974 ◽  
Vol 96 (4) ◽  
pp. 455-458 ◽  
Author(s):  
L. E. Wiles ◽  
J. R. Welty
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Natural Convection ◽  
Flat Plate ◽  
Convection Heat Transfer ◽  
Vertical Cylinder ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Flat Plates

An experimental investigation of laminar natural convection heat transfer from a uniformly heated vertical cylinder immersed in an effectively infinite pool of mercury is described. A correlation was developed for the local Nusselt number as a function of local modified Grashof number for each cylinder. A single equation incorporating the diameter-to-length ratio was formulated that satisfied the data for all three cylinders. An expression derived by extrapolation of the results to zero curvature (the flat plate condition) was found to agree favorably with others’ work, both analytical and experimental. The influence of curvature upon the heat transfer was found to be small but significant. It was established that the effective thermal resistance through the boundary layer is less for a cylinder of finite curvature than for a flat plate. Consequently, local heat transfer coefficients for cylinders are larger than those for flat plates operating under identical conditions.

Studies on Heat Transfer From a Vertical Cylinder, With or Without Fins, Embedded in a Solid Phase Change Medium

1985 ◽  
Vol 107 (1) ◽  
pp. 44-51 ◽  
Author(s):  
B. Kalhori ◽  
S. Ramadhyani
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Natural Convection ◽  
Solid Phase ◽  
Vertical Cylinder ◽  
Interface Shape ◽  
Fusion Temperature ◽  
Total Heat Transfer ◽  
Solid Liquid Interface ◽  
Solid Liquid

An experimental investigation of melting and cyclic melting and freezing around a vertical cylinder is reported. The studies encompass two cases: a plain vertical cylinder, and a vertical cylinder with fins. In the melting studies, the total heat transfer from the cylinder was measured as a function of time. In addition, measurements have been made of the solid-liquid interface shape after various melting times. In these studies, the solid phase was initially isothermal and either at its fusion temperature or subcooled below the fusion point. The experiments reveal the important influence of natural convection in the liquid phase in both unfinned and finned situations. Subcooling of the solid phase is observed to strongly inhibit heat transfer in the unfinned situation. In the experiment on cyclic melting and freezing, subcooling of the solid phase is once again found to have an important effect on the unfinned situation. Heat transfer from the finned cylinder is much less affected by solid-phase subcooling. All the experiments were performed with 99 percent pure n-eicosane paraffin.

The Effect of the Thermal Boundary Condition on Transient Method Heat Transfer Measurements on a Flat Plate With a Laminar Boundary Layer

1996 ◽  
Vol 118 (4) ◽  
pp. 831-837 ◽  
Author(s):  
R. J. Butler ◽  
J. W. Baughn
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Boundary Condition ◽  
Thermal Boundary Condition ◽  
Uniform Heat Flux ◽  
Transient Method ◽  
Uniform Temperature ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Numerical Predictions

The heat transfer coefficient distribution on a flat plate with a laminar boundary layer is investigated for the case of a transient thermal boundary condition (such as that produced with the transient measurement method). The conjugate problem of boundary layer convection with simultaneous wall conduction is solved numerically, and the predicted transient local heat transfer coefficients at several locations are determined. The numerical solutions for the surface temperature are used to determine the Nusselt number that would be measured in a transient method experiment for a range of (nondimensionalized) surface measurement temperatures (liquid crystal temperatures when they are used as the surface sensor). These predicted transient method results are compared to the well-known results for uniform temperature and uniform heat flux thermal boundary conditions. Measurements are made and compared to the numerical predictions using a shroud (transient) experimental technique for a range of nondimensional surface temperatures. The numerical predictions and measurements compare well and both demonstrate the strong effect of the (nondimensional) surface temperature on transient method measurements. Transient method measurements will give heat transfer coefficients that range from as low as that of the uniform temperature case to higher than that of the uniform heat flux case (a 36 percent difference). These results demonstrate the importance of the temperatures used with the transient method.

Estimation of Neutral Plane Position in High Rise Buildings

1996 ◽  
Vol 14 (3) ◽  
pp. 235-248 ◽  
Author(s):  
Y. He ◽  
V. Beck
Keyword(s):  
Experimental Data ◽  
Pressure Distribution ◽  
Network Model ◽  
Neutral Plane ◽  
Computational Results ◽  
Uniform Temperature ◽  
Simple Method ◽  
High Rise ◽  
Temperature Distributions ◽  
Smoke Spread

This paper presents a simple method for calculation of the pressure distribution and the neutral plane position in a high rise building. Non-uniform temperature distributions in the stairshaft of the building and discrete door openings are taken into account. The method has been incor porated into a network model for calculating smoke spread in multi-storey buildings. Computational results are compared with experimental data ob tained by other researchers.

Pseudo Bond Graph Modeling and Experimental Investigation of Thermal Transfers Inside a Household Refrigerator

2016 ◽  
Vol 24 (02) ◽  
pp. 1650014 ◽  
Author(s):  
Emna Aridhi ◽  
Mehdi Abbes ◽  
Abdelkader Mami
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Natural Convection ◽  
Graph Model ◽  
Bond Graph ◽  
Performance Comparison ◽  
Evaporator Temperature ◽  
Graph Modeling ◽  
Bond Graph Modeling ◽  
Simulation Results

This paper proposes a pseudo bond graph model of thermal transfers by natural convection inside a household refrigerator. It has two inputs: the ambient temperature and the temperature at the level of the evaporator wall. The latter assesses the functioning of the compressor cycles. A performance comparison, with the experimental data, was carried out in order to verify the model, in which, real measurements are used to modulate the evaporator temperature source. The simulation results show the effectiveness of the proposed approach.

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