Showing papers on "Fin (extended surface) published in 1971"
TL;DR: In this article, the authors present an experimental method for determining the variation of the local heat transfer coefficient around gas turbine blades, which involves the accurate determination of the distillation coefficient of the turbine blades.
Abstract: This paper presents an experimental method for determining the variation of the local heat transfer coefficient around gas turbine blades. The method involves the accurate determination of the dist...
77 citations
TL;DR: In this paper, the authors show that surface roughness has a particular effect on forced convection heat transfer to supercritical fluid and that the wall temperature profiles obtained in the experiments and also in those of previous investigators can be explained fairly well by the theory assuming normal mode turbulent convection.
53 citations
Patent•
27 Apr 1971
TL;DR: In this article, a tube and fin heat exchanger is presented, in which tube means are mounted in elongated slots in header plates for flow of a first fluid longitudinally through the tube means.
Abstract: A tube and fin heat exchanger in which tube means is mounted in elongated slots in header plates for flow of a first fluid longitudinally through the tube means. The tube means is constructed to provide a broad and flat heat transfer surface on its sides, and strip fin material is mounted to such sides and provides for flow of a second fluid over such surfaces. According to a feature of the invention the interior of the tube means is partitioned and ends of the tube means and end applied manifold members uniquely cooperate for multi-pass flow of the first fluid through the tube means.
44 citations
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TL;DR: In this paper, the authors developed an expression for the half fin height, and the volume of the resulting fin is optimized with respect to the temperature distribution parameter, which yields a minimum volume fin.
Abstract: Using the steady-state nonlinear differential equation which controls the temperature distribution in a fin of variable cross-section that is exchanging heat with the surroundings by convection and radiation, and an assumed form of the temperature distribution, an expression for the half fin height is developed, and the volume of the resulting fin is found. The total volume of the fin is optimized with respect to the temperature distribution parameter, and the half fin height thus found yields a minimum volume fin. The general solution yields the Schmidt solution for a simple convection fin, and the Wilkens solution for a simple radiation fin. An example problem is solved to find the half fin height for a minimum volume fin that is exchanging heat with the surroundings by convection and radiation.
34 citations
TL;DR: In this paper, the principle and experimental results of a thermally superconductive device, the liquid fin, were presented, and a comparison with the heat pipe was given, based on which a comparison of the two devices was made.
22 citations
22 citations
Patent•
23 Mar 1971
TL;DR: A finned tube heat exchange conductor has as its fin a continuous wire helix of undulating configuration characterized by outwardly extending loops between the points of securement as discussed by the authors, which is a type of wire-helix.
Abstract: A finned tube heat exchange conductor has as its fin a continuous wire helix of undulating configuration characterized by outwardly extending loops between the points of securement.
21 citations
TL;DR: In this paper, the authors made estimates of the rate of heat and mass transfer by molecular streaming, diffusion, convection and radiation during crystal growth in a pressure-pulling system.
17 citations
TL;DR: In this paper, the authors studied heat transfer between intact leaves of various sizes and shapes in vivo under free and forced air conditions, using a wind tunnel and a microwave transmitter to heat the leaves.
Abstract: Heat transfer was studied between intact leaves of various sizes and shapes in vivo under free and forced air conditions. Use of a wind tunnel and a microwave transmitter to heat the leaves facilitated measurements of convective, along with radiative and evaporative, heat losses from plant leaves. Knowledge of input energy, analysis of cooling curves, and established formulae, respectively, formed the basis of the steady-state, unsteady-state, and analytical methods for the determination of heat transfer coefficients.
17 citations
Patent•
07 Jun 1971TL;DR: In this paper, a manifolded core is constructed for multiple pass flow of at least one of the involved fluids, achieving localized crushing engagement with the fin material providing for separation of adjacent flow passes without the use of dividing channel and like separable component parts.
Abstract: A compact heat exchanger of the plate and fin type in which a manifolded core is constructed for multiple pass flow of at least one of the involved fluids. Manifold members have ribs achieving localized crushing engagement with the fin material providing for separation of adjacent flow passes without the use of dividing channel and like separable component parts.
16 citations
01 Dec 1971
TL;DR: In this paper, the effects of surface roughness on boundary layer transition and aerodynamic heating were investigated using a thin-skin model of the MDAC 256-20 space shuttle booster mated with a Stycast model of an internal tank orbiter.
Abstract: The collection and analysis of aerodynamic heating data obtained from shock impingement experimental investigation were completed. The data were categorized into four interference areas; fin leading edge, wing/fuselage fin/plate corners, and space shuttle configurations. The effects of shock impingement were found to increase the heating rates 10 to 40 times the undisturbed values. A test program was completed at NASA/Langley Research Center to investigate the magnitudes and surface patterns of the mated shock interference flowfield. A 0.0065 scale thin-skin model of the MDAC 256-20 space shuttle booster mated with a Stycast model of the MDAC Internal tank orbiter was tested in the 20-inch M=6 tunnel, the 31-inch M=10 tunnel, and the 48-inch Unitary Plan Tunnel. The gap region of the ascent configuration was the principal area of interest where both thermocouple and phase-change paint data were obtained. Pressure and heat transfer distributions data on the leeward surface of a 75-degree sweep slab delta wing are presented. The effects of surface roughness on boundary layer transition and aerodynamic heating were investigated.
Patent•
22 Nov 1971TL;DR: In this article, the authors propose a method of making good threetime interchanges between a TUBE WALL and a tube INSTALLED FIN ANNULUS, providing a secondary heat transfer surface.
Abstract: A METHOD OF ACHIEVING GOOD THERMAL INTERCHANGE BETWEEN A TUBE WALL AND A TUBE INSTALLED FIN ANNULUS, PROVIDING SECONDARY HEAT TRANSFER SURFACE, WHEREIN FIN CORRUGATIONS ARE METALLURGICALLY BONDED TO THE TUBE WALL BY A METHOD INHIBITING THE BONDING MATERIAL FROM FLOWING TO AND BLOCKING FLOW PATHS BETWEEN THE FIN CORRUGATIONS. A NEW FIN MATERIAL IS USED WHICH MAINTAINS OPEN FLOW PATHS THROUGH THE FIN MATERIAL EVEN WHEN THE MATERIAL IN STRIP FORM IS ROLLED TO A CIRCULAR OR ARCUATE CONFIGURATION. D R A W I N G
TL;DR: In this article, two 22 A-H nickel-cadmium cells were continuously cycled at a 1C charge rate and a 2C discharge rate, with cooling provided by an intercell planar heat pipe.
Abstract: Two 22 A-H nickel-cadmium cells were continuously cycled at a 1C charge rate and a 2C discharge rate, with cooling provided by an intercell planar heat pipe. For comparison, thermocouple measurements were also taken with an aluminum conduction fin substituting for the heat pipe. Thermally insulated cells were also cycled at the same rates. Cell case temperatures were measured during cycling, and a maximum of 29/sup 0/C with a 5/sup 0/C thermal excursion was noted with the heat pipe under conditions of thermal equilibrium which were observed after 3 complete cycles. For the aluminum fin configuration a maximum of 42/sup 0/C with a 7/sup 0/C thermal excursion was obtained near thermal equilibrium after 5 complete cycles. The insulated configuration yielded a case temperature of 83/sup 0/C after 5 cycles, and thermal equilibrium was never reached. Coulombic efficiency values for the heat pipe cooled battery were greater than 95% which was recorded for the fin configuration. The specific heat of the cells was measured. The effectiveness of the heat pipe in removing battery heat was calculated to be approximately 26% greater than the aluminum fin at or near equilibrium.
TL;DR: In this article, an experimental study of the heat transfer and gas flow on the surface of a semicone and of planar wings with a break in the leading edges at Mach number M=5 is presented.
Abstract: Results are presented of an experimental study of the heat transfer and gas flow on the surface of a semicone and of planar wings with a break in the leading edges at Mach number M=5. It is shown that with the interaction of the gas streams flowing about various portions of the surface of such bodies there may occur local, relatively narrow zones of high or low values of the specific heat flux.
TL;DR: In this paper, a method for studying convective heat transfer in transverse flow over a wire, from the temperature dependence of the heat transfer coefficients, was described, for temperature differences up to 1000°C and Re values from 0.14 to 2.
Abstract: A method is described for studying convective heat transfer in transverse flow over a wire, from the temperature dependence of the heat transfer coefficients. A formula has been obtained for calculating convective heat transfer in gas flow over a. wire, for temperature differences up to 1000°C and Re values from 0.14 to 2.
TL;DR: In this paper, the authors present a method for the heat transfer analysis of a circulating oil cooled cable system with emphasis on evaluation of heat transfer mechanism between the circulating oil and the cable components.
Abstract: This paper presents a method for the heat transfer analysis of a circulating oil cooled cable system with emphasis on evaluation of the heat transfer mechanism between the circulating oil and the cable components. Based on a review of the iiterature the conclusion was that there is a lack of available test data which can be directly applied to this specific case. It was determined that the oil film heat transfer mechanism is a combination of forced and free convection. Evaluating these two individually and treating them as separate resistances in parallel leads to the conclusion that if the oil flow is laminar the forced convection resistance is mnuch greater than the free convection resistance. Thus conservative forced cooled ratings can be obtained by-neglecting forced convection and calculating oil film resistances based on free convection only.
Patent•
01 Jul 1971
TL;DR: One substance gives up its heat (or cold) by convection to rotating bodies, and the other substance concerned in the heat transfer flows against these bodies, which steadily attain maximum temp. on every surface part, through convection and thermal flow.
Abstract: One substance gives up its heat (or cold) by convection to rotating bodies. The other substance concerned in the heat transfer flows against these bodies, which steadily attain maximum temp. on every surface part, by convection and thermal flow.
TL;DR: In this article, an experimental investigation of the heat exchange and hydraulic resistance of heat-transmitting elements with short finned ribs is presented. Butts et al. investigated the influence of the relative fin length and their mutual disposition on the characteristics of these elements and compared them for size and weight indices in the investigated range of numbers Re=200-4000.
Abstract: Results are presented of an experimental investigation of the heat exchange and hydraulic resistance of heat-transmitting elements with short finned ribs. The influence of the relative fin length and their mutual disposition on the characteristics is examined. Heat-transmitting elements are compared for size and weight indices in the investigated range of numbers Re=200–4000 for the case of their application in gas-turbine engine regenerators.
TL;DR: In this article, perfect boiling fin design in horizontal right circular cylinder shape, deriving formulas at peak heat flux operation, is described, and the optimal boiling fin size is obtained.
Abstract: Perfectly effective boiling fin design in horizontal right circular cylinder shape, deriving formulas at peak heat flux operation
Patent•
13 Jul 1971TL;DR: In this paper, a wire fin is formed along the length of a tubular member of a heat exchanger, with axially spaced portions bent around an arcuate segment of the outer periphery of the tube for conductive heat transfer.
Abstract: In preferred form, a heat exchanger including an elongated tubular member, with a wire fin formed along the length thereof. The fin has a plurality of axially spaced portions bent around an arcuate segment of the outer periphery of the tube for conductive heat transfer between the fin and tube. Other portions of the wire fin are looped radially outwardly of each of the bent portions to form a flow passageway between the fin and tube for convective heat transfer.
TL;DR: In this article, the heat conduction through the annular fin is analyzed and the fin efficiency is corrected to account for the radial nonuniformity of the heat transfer distribution.
Abstract: It is shown here how the heat transfer intensity distributes over the surface of annular fins cooled by a transversely moving heap of dense loose material. The heat conduction through the fins is analyzed and the fin efficiency is corrected to account for the radial nonuniformity of the heat transfer distribution.
TL;DR: In this article, the heat transfer coefficient and slow burnout heat flux were measured for a stream-water annular dispersed upward flow under pressures up to 3.5 ata in an electrically heated vertical annular channel.
Abstract: The heat transfer coefficient and slow burnout heat flux were measured for a stream-water annular dispersed upward flow under pressures up to 3.5 ata in an electrically heated vertical annular channel. An empirical equation was derived for the heat transfer coefficient as function of mass flow rate, steam quality and heat flux. The dominant mechanism of heat transfer to the annular dispersed two-phase flow is forced convection of liquid film on the heater surface even in the region of low steam quality (down to about 0.03). The observed slow burnout heat flux was near the point of intersection of the lines representing liquid film forced convective heat transfer and nucleate boiling heat transfer on the q vs. δT sat diagram. A dryout mechanism is proposed in which increasingly violent evaporation comes to impede the rewetting of the dry patches generated on the heater surface, which thus spread to cover the whole surface. A maximum value is observed in the slow burnout heat flux plotted against exit steam...
TL;DR: In this paper, an analysis of radiative and conductive heat transfer in parallel plates with lateral supply (removal) of heat is given, and an approximation method for the solution of heattransfer equations is presented, and the results of the calculations are represented by nomograms.
Abstract: An analysis is given of radiative and conductive heat transfer in parallel plates with lateral supply (removal) of heat. An approximation method for the solution of heattransfer equations is presented, and the results of the calculations are represented by nomograms.
TL;DR: In this article, it was shown that the difference between the temperature at any location and the surface temperature in a body with no heat generation and surface temperature ƒ4(t) is the same as that in a given body with constant surface temperature and volumetric heat generation Q = − Cϱ ∂ ǫ 4 −4∂t.
TL;DR: In this paper, the effect of uniform internal heat generation on fully developed velocity profiles, temperature profiles, pressure drops and Nusselt numbers is studied for combined free and forced laminar convection with upward flow in inclined tubes subjected to a uniform heating at the tube wall.
01 Sep 1971
TL;DR: In this paper, the conduction fin and VCF radiators were evaluated and an optimum was selected for rejecting waste heat from the Potassium Rankine cycle powerplant, and a comparison was made with an operationally equivalent conduction-fin radiator.
Abstract: A structurally integrated vapor chamber fin (heat pipe) radiator is defined and evaluated as a potential candidate for rejecting waste heat from the potassium Rankine cycle powerplant. Several vapor chamber fin geometries, using stainless steel construction, are evaluated and an optimum is selected. A comparison is made with an operationally equivalent conduction fin radiator. Both radiators employ NaK-78 in the primary coolant loop. In addition, the Vapor Chamber Fin (VCF) radiator utilizes sodium in the vapor chambers. Preliminary designs are developed for the conduction fin and VCF concepts. Performance tests on a single vapor chamber were conducted to verify the VCF design. A comparison shows the conduction fin radiator easier to fabricate, but heavier in weight, particularly as meteoroid protection requirements become more stringent. While the analysis was performed assuming the potassium Rankine cycle powerplant, the results are equally applicable to any system radiating heat to space in the 900 to 1400 F temperature range.