Showing papers on "Concentric tube heat exchanger published in 1976"

Method of manufacturing a concentric tube heat exchanger

Abstract: A method is provided for manufacturing a concentric-tube heat exchanger which includes at least a pair of concentric tubes disposed one within the other to form an annular longitudinally extending flow channel in which a plurality of heat transfer promoting fins reside. The method includes the step of applying a radially directed force to one of the pair of concentric tubes in sufficient magnitude to permanently deform the tube into engagement with the plurality of heat transfer promoting fins.

Toroidal multifluid segmented heat exchanger

Abstract: A plurality of segmented components are arranged to form a fixed radial heat exchanger. Each segment is an independent heat exchanger having a core of fluid tubes and air flow corridors between the tubes. Air flow is maintained through the heat exchanger by means of a propeller type fan mounted coaxially with the heat exchanger.

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

Electrically heated liquid tank employing heat pipe heat transfer means

Abstract: The heating apparatus for applying heat to the interior of a chamber includes a modular, removable, electrical, heat-producing unit and a heat pipe mountable in a wall of the chamber with one end of the pipe arranged to receive heat from the electrical heat producing unit exterior of the housing and with another end of the pipe constructed and arranged to apply heat to the medium within the chamber. The heat pipe has high conductivity with a low temperature differential between the ends thereof and the heat producing unit includes an electric coil positioned about and removably secured to the one end of the heat pipe. The electric coil is embedded in a high thermal conductivity, low electrical conductivity filler material which is surrounded by a low thermal conductivity insulating jacket and which is received around a metal core member which is removably secured to the one end of the heat pipe.

Matrix heat exchanger including a liquid, thermal couplant

Abstract: A tube-to-tube heat exchanger is disclosed with a thermally conductive matrix between and around the tubes to define annuli between the tubes and matrix The annuli are filled to a level with a molten metal or alloy to provide a conductive heat transfer path from one tube through the matrix to the second tube A matrix heat exchanger of this type is particularly useful for heat transfer between fluids which would react should one leak into the second

Effect of electrically induced convection on heat transfer of air flow in an annulus

Abstract: This paper presents the results of an investigation of heat transfer to a flow of air in an annulus under an electric field applied between the wall of a tube and a concentric wire electrode. By electrically induced disturbance, the heat transfer rate in the low Reynolds number region is increased, being accompanied by the augmentation of axial pressure drop. At high Reynolds number, however, this augmentation is not noticiable. Augmented heat transfer and pressure drop coefficients were correlated in non-dimensional terms derived from the similarity principle and analytical cinsideration of the predominant electric effect. Moreover, semiempirical formulations of these augmenting mechanisms were attempted by analyzing the measured temperature profiles and flow behaviour.

Heat exchanger with intermediate evaporating and condensing fluid

Abstract: A shell and tube-type heat exchanger, such as a liquid sodium-operated steam generator for use in nuclear reactors, comprises a shell containing a primary fluid tube bundle, a secondary fluid tube bundle at higher elevation, and an intermediate fluid vaporizing at the surface of the primary fluid tubes and condensing at the surface of the secondary fluid tubes.

Method and apparatus for controlling surface temperature

Abstract: A method and apparatus are disclosed for automatically controlling the surface temperature of a body by removing heat from the body with a first heat exchange liquid circulating between a heat exchanger in contact with the body and a second heat exchanger in which heat is transferred from the first heat exchange liquid to a second, more volatile, heat exchange liquid in boiling equilibrium with its vapor. The temperature of the second heat exchange liquid, and consequently the amount of heat removed from the body being cooled, is controlled by regulating the pressure in the second heat exchanger in inverse proportion to the temperature of the body being cooled. This abstract is not to be construed in any way to define or limit the invention set forth below.

Heat exchanger for nuclear reactor system - using U-tubes in symmetrical arrangement with central axial manifold and radial tube sheet (OE 15.3.77)

Abstract: In a cylindrical heat exchanger, the hot fluid enters axially and flows across radially arranged U-tubes leaving by annular ports. The U-tubes carry cold fluid and are disposed radially with their outer ends in a radial annular tube sheet. The inner tube ends connect to an axial manifold which forms the outlet duct. For use as intermediate heat exchanger for nuclear reactors, with the primary fluid entering at some 950 degrees C and being cooled to 250 degrees, and the secondary circuit having an inlet temp. of about 200 degrees C and an outlet of 900 degrees C. The symmetrical construction avoids temp. stresses partic. in tube plates and allows large heat exchanger surfaces in relatively small over-all dimensions.

Solar energy heat exchanger and method for making same

Abstract: A fluted strip of heat conducting material is spirally wound edgewise about a length of pipe and, in combination, define a heat exchanger for receiving solar energy. The lateral edges of the flutes forming the outer edge of the strip define an undulating line superimposed upon a helix. The lateral edges of the flutes forming the inner edge of the strip define an undulating line superimposed upon a sinusoidal curve which, in turn, is superimposed upon a helix. Thereby, cyclically repetitive ones of the flutes become oriented normal to the rays of the sun to effect maximum heat transfer as the angle of incidence to the heat exchanger varies. A method for producing the heat exchanger is also described.

Errors in heat transfer laws for constant temperature hot wire anemometers

Abstract: A number of conflicting semi-empirical heat transfer laws for forced convective heat transfer from fine hot wires have been reported, e.g. Collis and Williams (1959), Bradbury and Castro (1972) and Koch and Gartshore (1972). It is shown that the discrepancy between these results can be explained by the use in some experiments of a non-ideal 'constant temperature' feedback system.

Auxiliary cooling device for the primary fluid heat exchanger of a nuclear reactor

Abstract: An auxiliary cooling device for a primary fluid heat exchanger of a rapid neutron nuclear reactor, the exchanger having at least one nest of tubes in which there flows water to be heated to superheated steam and around whose tubes and inside whose casing there flows a liquid alkaline metal constituting the primary fluid. The casing of the exchanger is surrounded by a jacket having an air inlet tube and an air outlet tube at opposite ends. Inside the jacket there are auxiliary heat exchange surfaces such as spikes projecting from the casing of the primary heat exchanger proper. Application is to the absorption of residual power produced by a rapid neutron reactor after it is shut down.

Cooling drying plant for compressed air - has coaxial or stacked heat exchangers with tube within tube elements

Abstract: The cooling drying plant for pressurised gases, esp. for compressed air, has vertical gas and gas heat exchanger and gas and coolant heat exchanger. The gas to be dried is continuously circulated successively through gas and gas heat exchanger and gas and coolant heat exchanger. The dryer operates without pressure vessel or may have only a small pressure vessel. The gas and gas heat exchanger (12) and gas and coolant heat exchanger can be coaxial. These heat exchangers are built up of exchanger elements (59) of tube within tube arrangements. These elements are connected to circular collector chambers (45) of small cross section. The heat exchangers can be stacked so that inner tubes (62) pass without interruption through both exchangers. Several inner tubes (62) can be arranged into an external tube (61).

CONRAD: Heat conduction-radiation code, part 1

Abstract: A computer code is developed for two-dimensional, non-steady heat conduction in heterogeneous, anisotropic solids with nonuniform volumetric internal heating. Thermal radiation and arbitrary heat flux boundary conditions are accommodated. Coolant tubes are taken into account by prescribing fluid temperatures and heat transfer coefficients. With regard to coolant tubes, allowance is made for: (a) heat capacitance in the tube wall, coolant tube in contact with the structural material; (b) zero heat capacitance in the tube wall, coolant tube in contact with the structural material; and (c) zero heat capacitance in the tube wall, radiation gap between the wall and structure. The finite difference equations are solved by the standard explicit method. Stability as well as convergence of the iterative process are considered.

Analysis of Large Dry Cooling Towers With Power-Law Heat Exchanger Performance

Abstract: An analysis is presented for heat exchanger area, tower exit area, and exchanger tube length and number, for heat exchangers in large dry cooling towers, having performance parameters given by powers of Reynolds number, but otherwise under very general cooling-cycle constraints. The calculation method is illustrated for a ''spin-fin'' heat exchanger which, in a tube size of about /sup 3///sub 8/ in., seems capable of achieving low tower size in a practical device. Calculations, over ranges of water pumping power, approach, ITD, number of passes, tube size, tower shape (natural draft) or fan power (mechanical draft), and ambient pressure altitude are shown to be well represented by a chain of powers of these variables, and certain functions of the ratio of real to ideal tower exit area. This ratio is shown to have a best value, depending on the cost coefficients of heat exchange and exit areas, and it is pointed out that typical cost proportions lead to a fluid-mechanical ''packaging'' problem for the shallow heat exchangers which would be preferred.

Heat transfer in tube bundles of heat exchangers with flow baffles induced forced mixing

Abstract: Thermal analysis of shell-and-tube heat exchangers is being investigated through geometric modeling of the unit configuration in addition to considering the heat transfer processes taking place within the tube bundle The governing equations that characterize the heat transfer from the shell side fluid to the tube side fluid across the heat transfer tubewalls are indicated The equations account for the heat transfer due to molecular conduction, turbulent thermal diffusion, and forced fluid mixing among various shell side fluid channels The analysis, though general in principle, is being applied to the Clinch River Breeder Reactor Plant-Intermediate Heat Exchanger, which utilizes flow baffles appropriately designed for induced forced fluid mixing in the tube bundle The results of the analysis are presented in terms of the fluid and tube wall temperature distributions of a non-baffled and baffled tube bundle geometry The former case yields axial flow in the main bundle region while the latter is associated with axial/cross flow in the bundle The radial components of the axial/cross flow yield the necessary fluid mixing that results in reducing the thermal unbalance among the heat transfer to the allowable limits The effect of flow maldistribution, present on the tube or shell sides of themore » heat exchangers, in altering the temperature field of tube bundles is also noted« less

Fin tube distribution nozzle

Abstract: A spray nozzle with a discharge surface defined by the formula X = ± 0.875D-t-0.5y- √0.75Dy, with D being the outside diameter of a connected heat exchanger tube, and t being the thickness of such heat exchanger tube, does not create sufficient back pressure to destroy the thin film layer of liquid flowing down the inside of such heat exchanger tube.

Local heat exchange of a single transversely bathed round tube with external circular fins

Abstract: Under conditions of transverse bathing of a finned tube by air the distributions of local heat-transfer coefficients on the lateral faces and ends of a circular fin and on the fin-free surface of the tube proper are determined using heat-flux pickups.

Steady two-phase flow in a vertical tube subject to combined free and forced convection

Abstract: Using the two-velocity, two-temperature model of a continuous medium, the viscousgravitational flow of a mixture of incompressible liquid and solid particles in a vertical round tube is considered. The free-convection equations are written down on the basis of the general equation of motion and the energy equation of a two-phase medium [1, 2]. Using a finite Hankel integral transformation, a solution is constructed for the case of a linear wall-temperature distribution along the tube. The results of some practical calculations of the velocity and temperature fields over the cross section of the tube are presented, together with the dimensionless heat-transfer coefficient expressed as a function of the Rayleigh number and phase concentration. Here it is assumed that the dynamic and thermal-interaction coefficients between the phases correspond to the Stokes mode of flow for each particle, as a result of which the velocity and thermal phase lag is very small [3].

Experimental investigation of heat transfer in the annular channel of a circulation loop

Abstract: The results of an experimental investigation of heat transfer in the vertical annular channel of a closed circulation heat exchanger are given.