EXPERIMENTAL STUDIES OF NATURAL CONVECTION IN A HORIZONTAL CYLINDER

1974 ◽  
Author(s):  
Ali Sabzevari ◽  
Simon Ostrach
Keyword(s):  
Natural Convection ◽  
Experimental Studies ◽  
Horizontal Cylinder

Onset of Natural Convection from a Suddenly Heated Horizontal Cylinder

1980 ◽  
Vol 102 (4) ◽  
pp. 636-639 ◽  
Author(s):  
J. R. Parsons ◽  
J. C. Mulligan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Stability ◽  
Heat Capacity ◽  
Natural Convection ◽  
Stability Analysis ◽  
Horizontal Cylinder ◽  
Finite Cylinder ◽  
Global Motion ◽  
Experimental Apparatus

A study of the onset of transient natural convection from a suddenly heated, horizontal cylinder of finite diameter is presented. The termination of the initial conductive and “locally” conuectiue heat transfer regime which precedes the onset of global natural convection is treated as a thermal stability phenomenon. An analysis is presented wherein the effects of finite cylinder diameter, cylinder heat capacity, and cylinder thermal conductivity are included in calculations of the convective delay time. A simple experimental apparatus is described and data presented. The thermal stability analysis is confirmed experimentally and data is presented which indicates localized natural convection prior to global motion.

Natural Convection from a Horizontal Cylinder—Laminar Regime

1981 ◽  
Vol 103 (3) ◽  
pp. 522-527 ◽  
Author(s):  
B. Farouk ◽  
S. I˙. Gu¨c¸eri
Keyword(s):  
Natural Convection ◽  
Horizontal Cylinder ◽  
Heat Transfer Characteristics ◽  
Convective Flows ◽  
Finite Difference Numerical Method ◽  
Temperature Boundary ◽  
Recirculation Zones ◽  
Boussinesq Fluid ◽  
Temperature Boundary Condition ◽  
Good Agreement

A finite-difference numerical method has been adopted to generate flow patterns and heat transfer characteristics for laminar, steady-state, two-dimensional natural convection around a circular cylinder submerged in an unbounded Boussinesq fluid. The approach allows the use of nonuniform as well as uniform specified temperature and heat flux distributions over the cylindrical surface. Part of the results are generated for reverse convective flows with recirculation zones which occur when part of the cylinder is below the ambient temperature while the remaining part is above. The results for uniform temperature boundary condition are in good agreement with the experimental data and other solutions available in literature.

A Natural Convection Model for the Rate of Salt Deposition From Near-Supercritical, Aqueous Solutions

2003 ◽  
Vol 125 (6) ◽  
pp. 1027-1037 ◽  
Author(s):  
Marc Hodes ◽  
Kenneth A. Smith ◽  
Peter Griffith
Keyword(s):  
Natural Convection ◽  
Deposition Rate ◽  
Water Oxidation ◽  
Molecular Diffusion ◽  
Horizontal Cylinder ◽  
Salt Deposition ◽  
Solution Interface ◽  
Salt Layer ◽  
Aqueous Salt Solutions ◽  
Convection Model

A model is developed for the rate of salt deposition by natural convection from aqueous salt solutions onto a horizontal cylinder heated beyond the solubility temperature for the dissolved salt. The model accounts for the deposition rate at the salt layer-solution interface (SLSI) formed on the cylinder, but it does not account for deposition which may occur inside the porous salt layer (PSL). Dissolved salt is transported to the SLSI by molecular diffusion (with advection) and subsequently nucleates heterogeneously there. The model is applied to the experimental deposition rate data acquired by Hodes et al. (1998, 2002) at conditions pertinent to Supercritical Water Oxidation (SWCO). The ratio of the predicted deposition rate to the measured one ranges from roughly 0.5 to 2 indicating that deposition inside the PSL can be considerable.

Integral Methods in Natural-Convection Flow

1955 ◽  
Vol 22 (4) ◽  
pp. 515-522
Author(s):  
Salomon Levy
Keyword(s):  
Natural Convection ◽  
Horizontal Cylinder ◽  
Convection Flow ◽  
Inclined Plate ◽  
Natural Convection Flow ◽  
Specific Flow ◽  
Integral Methods ◽  
Method Of Solution ◽  
Arbitrary Body ◽  
Variable Wall

Abstract This paper presents an evaluation of the range of application, accuracy, and usefulness of integral methods in natural-convection flow. The study reveals (a) that integral methods may be utilized to obtain approximate answers to free-convection problems whenever exact analytical solutions become too involved. Specific-flow examples considered here (natural convection from inclined plate, horizontal cylinder, arbitrary body, or within enclosed channels) confirm their adaptability to complicated configurations. (b) Over-all accuracy of the solutions is good. For inclined plates the derived equations reduce at high Grashof numbers to the correlation proposed and verified by Rich (1) while in the case of horizontal cylinders the results compare satisfactorily with the theoretical values of Hermann (2) and the accepted experimental relations (12). (c) The integral method of solution may be extended to apply to low Prandtl number fluids, laminar or turbulent flow, variable wall temperature, and convection within confined spaces.

Methods for calculating thermal processes under conditions of natural convection of gaseous methane under the influence of electrostatic fields

2021 ◽  
Author(s):  
V.A. Altunin ◽  
K.V. Altunin ◽  
M.R. Abdullin ◽  
M.R. Chigarev ◽  
I.N. Aliev ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Power Plants ◽  
Experimental Studies ◽  
Thermal Processes ◽  
Technical Literature ◽  
New Methods ◽  
Electric Wind ◽  
Electrostatic Fields ◽  
General Method

Relying on the review and analysis of scientific and technical literature, as well as the results of experimental studies, we developed new methods for calculating thermal processes occurring in gaseous methane during its natural convection, under the influence of electrostatic fields. In this study we show methods for calculating and determining the coefficients of heat transfer to gaseous methane under the influence of electric wind, as well as methods for calculating and determining the effect of electrostatic fields on the negative process of sedimentation on a heated experimental working plate in the volume of gaseous methane. A general method has been developed for the effective and safe application of electrostatic fields in gaseous methane, which must be carried out in the calculations, design, creation, and operation of new engines, power plants, and techno systems for single and reusable ground, air, aerospace and space-based aircraft.

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