Characteristics Of Fins Research Articles

Numerical Analysis on Two-Dimensional Flow and Heat Transfer of Louvered Fins Using Overlaid Grids

Using an overlaid grids method, finite difference analysis have been made on two-dimensional flow and heat transfer characteristics of louvered fins which comprise automotive heat exchangers used in the forced convection regime at low Reynolds number. In this method the physical domain is subdivided into some regions which can adapt easily to Cartesian grids. The maximum total number of the grid points allocated non-uniformly in the respective regions is about 100000. Communication between the grids is accomplished by linear interpolation of the dependent variables at grid boundaries. It took 3060 minutes of the CPU (supercomputer NEC SX-2) for the iterative computation. In the rage of Re=64450, the present numerical scheme was validated through the comparisons between the numerical results and the corresponding experimental data which were also obtained in the present study.

Numerical analysis on two-dimensional flow and heat transfer of louvered fins using overlaid grids.

Using an overlaid grids method, finite difference analysis have been made on two-dimensional flow and heat transfer characteristics of louvered fins which comprise automotive heat exchangers used in the forced convection regime at low Reynolds number. In this method the physical domain is subdivided into some regions which can adapt easily to Cartesian grids. The maximum total number of the grid points allocated non-uniformly in the respective regions is about 100000. Communication between the grids is accomplished by linear interpolation of the dependent variables at grid boundaries. It took 3060 minutes of the CPU (supercomputer NEC SX-2) for the iterative computation. In the rage of Re=64450, the present numerical scheme was validated through the comparisons between the numerical results and the corresponding experimental data which were also obtained in the present study.

Efficiency characteristics of crescent-shaped wings and caudal fins

Caudal (tail) fins of fish and aquatic mammals that cruise long distances, and wings of certain birds, often have the shape of a crescent moon. This study investigates how the crescent shape contributes to the travelling performance of these animals. A steady-flow theory1 that correctly models the trailing wake was used to analyse lifting surface efficiency, which is dependent on the level of induced (or vortex) drag for a given lift and span of the lifting surface. This analysis shows that backward curvature of a wing improves induced efficiency to a value greater than that of the flat untwisted wing of elliptical shape considered optimal in classical wing theory2,3. This increase of induced efficiency results from the nonplanar trailing vortex sheet produced by the crescent-shaped wing at a given angle of attack.

Plastic impact testing of shipping cask fin specimens

An impact test program was conducted to determine the energy absorption characteristics of typical heat transfer or structural fins on shipping casks as these fins undergo dynamic, gross plastic deformation. It was assumed that the energy absorption characteristics of fins welded parallel to the longitudinal axis of a cylindrical cask are linear with respect to their length, and the test program was designed to determine the energy absorption capability per inch of fin length along the cask body. Specimens of typical fin geometries were impacted with free-falling weight dropped from known heights, and the force-time relationships occurring during each impact were recorded. A computer program was used to convert the test data into deformation-time and energy-time relationships. These relationships were correlated in a set of curves that enable the cask designer or analyst to compute the energy absorption capacity of a longitudinal fin on a cask as a function of its geometry and the percentage of deformation it is expected to experience as well as the peak force the fin would experience during the impact resulting from a 30-ft free drop into an essentially unyielding horizontal surface.

Heat-transfer characteristics of polygonal and plate fins

Heat-transfer characteristics of polygonal and plate fins

Radiating Effectiveness of Annular-Finned Space Radiators, Including Mutual Irradiation Between Radiators Elements

The heat transfer characteristics of annular fin and tube radiators have been determined analytically. The complex interaction problem resulting from mutual irradiation between neighboring fins and between fins and the tube surface has been fully accounted for by applying a newly-devised contour-integral method for deriving the radiant interchange factors. The mathematical description of the simultaneous heat transport by conduction and radiation leads to a nonlinear integro-differential equation. This has been solved for a wide range of the pertinent physical parameters. The heat transfer from the fin-tube system has been calculated and is presented graphically in dimensionless form. The separate contributions to the total of the fin and of the tube are also shown. The results definitely indicate that the use of fins leads to a significant increase in heat transfer compared with the unfinned tube.