Showing papers on "Fin (extended surface) published in 1976"

Postaccident Heat Removal—Part I: Heat Transfer Within an Internally Heated, Nonboiling Liquid Layer

Abstract: Correlations of experimental data on heat transfer from nonboiling, horizontal fluid layers with internal heat generation have been cast into a form suitable for analysis of postaccident heat remov...

Thermal storage and heat transfer system and method

Abstract: A thermal storage and heat transfer system for use with a solar energy heat collector comprising a tank having a plurality of temperature zones therein each zone having, preferably, a plurality of layers of closely arranged cells of irregular shape occupying a minimum space to provide a maximum number of cells in said space in a manner to provide ample passages between the cells for a liquid heat transfer medium to contact and move past appreciable surface areas to effect heat transfer to and from said medium, said cells in said zones respectively having sealed therein different heat storage mediums of a nature to develope a substantially constant latent heat of fusion temperature when changing from liquid to solid state at a predetermined temperature, and a pump connected to said tank and operable to circulate said heat transfer medium through said passages from and to a solar heat collector. The prefered shape of said cells is a tetrahedron or a similar simple solid geometric configuration.

Error in Temperature Measurements Due to Conduction Along the Sensor Leads

Abstract: When a sensor is embedded in a solid body to measure its internal temperature, any conduction to or from its sensing element may cause the indicated temperature to be different from the true temperature. This paper describes an analysis of the error caused by conduction when there is an arbitrary temperature distribution in the body along the sensor. The sensor is modeled as a cylindrical fin and the appropriate conduction equation is solved. The solution gives a correction for the error which depends on such parameters as, depth of immersion, thermocouple wire and insulation properties, contact between the sensor and the body, and temperature distribution in the body. The latter may not be known, but the measured temperature distribution can be used as a first approximation. The corrected value can then be used to obtain a better estimate of the error. The results show good agreement with experimental observations.

Method of making an annular tube-fin heat exchanger

Abstract: A method of making a heat exchanger in which extended heat transfer material, such as a fin annulus composed of thin corrugated deformable metal, is installed in annular fluid flow paths defined between concentric tubes Concepts of electromagnetic forming and metallurgical bonding are used in a unique combination of steps to arrive at a method well suited to economical production and which at the same time assures a high efficiency level of heat transfer and leak protection effects

Single in-line high power resin-packaged semiconductor device having an improved heat dissipator

Abstract: A single in-line, high power, resin-packaged semiconductor device having a plurality of external leads disposed in parallel to each other and projecting from one side surface of a resin-molded package, wherein a heat sink fin mounting plate is formed in unitary structure with a plate for carrying a semiconductor pellet and arranged to project from a recessed portion of the opposite side surface of the resin-molded package and a heat sink fin has one end bent in U-shape and caulked on the fin mounting plate and the remaining portion overlapping one principal surface of the resin-molded package. The projection of the heat sink fin from the resin-molded package can be reduced to enable the device to be assembled in compact electronic instruments or devices. Heat dissipation efficiency can also be improved by mounting the semiconductor device on a chassis with the heat sink fin brought in contact with the chassis.

Wet/dry cooling tower and method

Abstract: A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.

Tubular solar collector

Abstract: An evacuated, double-walled, tubular housing contains a sheet metal fin which is biased against the inner tube. A metal tube carrying the fluid to be heated is placed in heat transfer relationship with the fin. A plurality of collectors can be placed in an array with the fluid carrying tubes the only connection.

Variational techniques applied to radiative-convective fins with steady and unsteady conditions

Abstract: An analysis is made for the heat transport characteristics of a longitudinal fin dissipating heat by radiation and convection simultaneously. The thermal properties of the fin material are assumed to be constant and the radiative exchange between the fin and its base is neglected. Two physical situations are presented. In one of these, the steady thermal process of the fin, exposed to constant environmental conditions, is studied using the Ritz method. In the other, the Kantorovich method is employed to examine the unsteady thermal behavior of the fin when the environmental conditions depend upon time. Computed results for the fin effectiveness are presented both in tabulated and graphical form for a wide variety of influencing parameters. The validity of these calculations is demonstrated utilizing finite-difference procedures.

Fin-line dispersion

Abstract: The dispersion of different fin-line geometries is calculated by applying Galerkin's method to the electric fields in the slot interface. The antipodal fin line is shown to be of high interest, since its wave impedance can easily be varied from very low to high values.

Method and apparatus for manufacturing a helically finned heat exchanger

Abstract: A method and apparatus is disclosed for the manufacture of a continuous heat exchanger tube including helically winding a spine fin material on the outer wall of a base tube member. A preselected portion of the spine fin material is secured against movement relative to the base tube member. The heat exchanger is then severed in the secured portion so that a section of the secured portion is arranged at each end of the severed heat exchanger. The secured severed end sections are effective in maintaining the intermediate portion of the spine fin material from unwinding and, as a result, in heat transfer relationship with the base tube member.

Heat insulation for tanks at cryogenic and higher temperatures, using structural honeycomb with integral heat radiation shields

Abstract: Heat insulation for structures such as cryogenic tanks for example liquid natural gas tanks, often referred to as LNG tanks, is effective at cryogenic and higher temperatures up to the heat and structural limits of the honeycomb materials used which include integral heat radiation shields. The heat transfer is minimized with respect to conduction, by utilizing the minimum heat path possible within the honeycomb also essentially designed to take compressive loads, with respect to radiation, by placing multiple low emissivity heat shields spaced throughout the hexagonal cells, and in respect to convection, by replacing air with a low conductivity gas, or alternately creating a vacuum, to practically eliminate this convection mode of heat transfer.

Cross fin type heat exchanger

Abstract: PURPOSE: A cross fin type heat exchanger to be able to heighten heat exchange efficiency in the whole of upper and lower reaches in air current direction by means of increasing heat transmitting area augmenting the pipe length of multiple rows of heat transmitting pipes in their order from upper reaches in the air current direction. COPYRIGHT: (C)1977,JPO&Japio

Performance of Crossflow Heat Exchanger

Abstract: In search of ways to obtain uniform outlet temperature distribution on crossflow heat exchangers, theoretical analyses by means of Laplace transformation are further developed, and experimental investigations are carried out on both the plate fin type and the fin tube type crossflow heat exchangers. The analyses and experiments are conducted under the conditions of (1) various distribution patterns of fluid flow rate and (2) various distribution patterns of heat transfer area, and the results thereof are compared. In consequence, by setting the fluid flow rate distribution, as confirmed by the analyses, uniform outlet temperature in an appreciable degree can be obtained over a wide range of NTU, and better temperature efficiency is achieved. By varying the heat transfer area distribution, similar results are obtained, but this method is impractical compared with the former.

Models for the Representation of Turbomachine Blades During Temperature Transients

Abstract: When the operating conditions of turbomachinery are changed, as when a gas turbine is accelerated, heat is transferred from or to the various components of the machine. One of the significant heat transfers is with the blading. Several simple models for the blade and platform arrangement are compared. Satisfactory representation is obtained from a simple eight-element Finite Difference Model and from a Revised Fin Model. Computer running times are similar, but the latter allows more convenient hand calculations and is more suitable when predicting the thermal response of casings or disks to which the blades are attached.Copyright © 1976 by ASME

Heat-resisting copper alloy having excellent electrical conductivity a nd thermal conductivity

Abstract: PURPOSE: To obtain the copper alloy having high softening temperature and large tensile strength, and suitable for the fin material of radiator, etc., by adding Mg, Sn and P jointly to Cu. COPYRIGHT: (C)1977,JPO&Japio

Study on Air Cooled Heat Exchanger with Corrugated Fin Surfaces : 1st Report. Fin Efficiency and Overall Efficiency of Straight Fin Surfaces.

Abstract: Fin efficiency and overall efficiency are very important factors to be considered in the design of finned heat exchangers. However, no suitable equation has been available to compute the efficiency of the fin surfaces, where heat conduction proceeds two-dimensionally through a thin strip and is influenced by heat conduction characteristics of the water tube walls. In this paper, equations for the fin efficiency and overall efficiency are presented for the following three cases. First, the approximate equation for fin efficiency, derived from numerical analysis in case of two-dimensional heat conduction through thin metal fins. Second, the equation for fin overall efficiency in consideration of heat conduction characteristics of the water tube walls, derived by analysis. Third, the equation for corrugated fin surface's overall efficiency derived from consideration of the influence of two-dimensional heat conduction through the fins and heat conduction characteristics of the water tube walls.

Sharp dual estimates for conductance of an optimal circular cooling fin

Abstract: A cooling fin attached to a cylinder of circular cross section is considered. We obtain sharp upper and lower estimates for the maximum heat dissipation under the constraint that the total weight of the fin should not exceed a given bound. It is assumed that the boundary of the cylinder has a constant temperature and that Newton's law of cooling holds.

Heat-sink for semiconductor oscillator - has voltage liquid vaporising in closed chamber to transfer heat to external cooling fin

Abstract: The heat sink is for a semiconductor oscillator and consists of an enclosed chamber which contains a volatile liquid (7). The semiconductor oscillator (1) is located in a hermetically sealed enclosure beneath the vessel and is in thermal contact with the thermally-conducting bottom plate of the chamber. Heat is transferred from the oscillator to the liquid, which then vaporises and condenses on the upper plate of the chamber. The upper thermally-conducting plate is connected to an external cooling fin (5) and the liquid chamber is provided with a pressure release valve (8) and is enclosed in insulating material (6).

TAP 1: A Finite Element Program for Steady-State Thermal Analysis of Convectively Cooled Structures

Abstract: The program has a finite element library of six elements: two conduction/convection elements to model heat transfer in a solid, two convection elements to model heat transfer in a fluid, and two integrated conduction/convection elements to represent combined heat transfer in tubular and plate/fin fluid passages. Nonlinear thermal analysis due to temperature dependent thermal parameters is performed using the Newton-Raphson iteration method. Program output includes nodal temperatures and element heat fluxes. Pressure drops in fluid passages may be computed as an option. A companion plotting program for displaying the finite element model and predicted temperature distributions is presented. User instructions and sample problems are presented in appendixes.

Manufacture of finned heater

Abstract: PURPOSE:A finned heater for heating ambient atmisphere which is manufactured by pressing a pipe together with a heater plug, the diameter of the pipe corresponding to the fin length.