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Showing papers on "Heat pipe published in 1988"


Patent
15 Jun 1988
TL;DR: In this paper, a structure of a loop-type heat pipe is disclosed in which a heat carrying fluid, preferably a bi-phase non-condensative fluid, circulates in a loop form in itself under its own vapor pressure at a high speed within an elongate pipe so as to repeat vaporization and condensation, thus carrying out a heat transfer.
Abstract: A structure of a loop-type heat pipe is disclosed in which a heat carrying fluid, preferably a bi-phase non-condensative fluid, circulates in a loop form in itself under its own vapor pressure at a high speed within an elongate pipe so as to repeat vaporization and condensation, thus carrying out a heat transfer. A structure of the loop-type heat pipe includes the elongate pipe, both ends thereof being air-tightly interconnected to form a loop-type container, the heat carrying fluid, at least one heat receiving portion and at least one heat radiating portion, both being placed at given portions of a elongate pipe, and at least one check valve for limiting a stream direction of the heat carrying fluid. A check valve(s) propels and amplifies forces generated by the heat carrying fluid and its vapor to move toward the stream direction limited by the check valve(s) so that the heat carrying fluid circulates in the stream direction through the closed-loop passage defined by the elongate pipe at the high speed, repeating vaporization at the heat receiving and radiating portions.

358 citations



Book
01 Jul 1988
TL;DR: In this article, a comprehensive presentation is made of state-of-the-art configurations and design methodologies for heat transfer devices applicable to industrial processes, automotive systems, air conditioning/refrigeration, cryogenics, and petrochemicals refining.
Abstract: A comprehensive presentation is made of state-of-the-art configurations and design methodologies for heat transfer devices applicable to industrial processes, automotive systems, air conditioning/refrigeration, cryogenics, and petrochemicals refining. Attention is given to topics in heat exchanger mechanical design, single-phase convection processes, thermal design, two-phase exchanger thermal design, heat-transfer augmentation, and rheological effects. Computerized analysis and design methodologies are presented for the range of heat transfer systems, as well as advanced methods for optimization and performance projection.

121 citations


Patent
18 Jul 1988
TL;DR: In this article, a CERDIP housing is provided with a heat pipe that passes through the closure seal lid whereby the heat pipe terminates within the housing cavity at the hot end thereof.
Abstract: A CERDIP housing is provided with a heat pipe that passes through the closure seal lid whereby the heat pipe terminates within the housing cavity at the hot end thereof. A quantity of working fluid, such as fluorinated octane, is contained within the package cavity. The heat pipe communicates with cooling fins that produce a cold end thereof. Heat from the semiconductor device inside the housing boils the working fluid and is cooled thereby. The fluid vapor passes along the heat pipe and is condensed at the cold end to be converted back to liquid. As a result the semiconductor device is in direct communication with the heat pipe working fluid.

113 citations


Patent
26 Aug 1988
TL;DR: In this article, the authors improved on the indirect evaporative cooling method and apparatus by making use of a working fluid that is pre-cooled with and without desiccants before it is passed through a Wet Channel where evaporative fluid is on the walls to take heat and store it in the working fluid as increased latent heat.
Abstract: The within invention improves on the indirect evaporative cooling method and apparatus by making use of a working fluid that is pre-cooled with and without desiccants before it is passed through a Wet Channel where evaporative fluid is on the walls to take heat and store it in the working fluid as increased latent heat. The heat transfer across the membrane between the Dry Channel and the Wet Channel may have dry, solid desiccant or liquid desiccant and may have perforations, pores or capillary pathways. The evaporative fluid may be water, fuel, or any substance that has the capacity to take heat as latent heat. The Wet Channel or excess cooled fluid is in heat transfer contact with a Product Channel where Product Fluid is cooled without adding any humidity. An alternative embodiment for heat transfer between adjacent channels is with heat pipes.

96 citations


Patent
27 Jun 1988
TL;DR: In this paper, a sealed bellows type container with an evaporator section at one end and a condenser section at an opposite end is used to conduct heat away from an electronic device to a heat sink.
Abstract: A bellows type heat pipe which conducts heat away from an electronic device to a heat sink. The heat pipe is a sealed bellows type container which has an evaporator section at one end and a condenser section at an opposite end. The evaporator section contains a saturated radial wick while the condenser section is lined with a radial wick and a circumferential wick. A corrugated slab wick is longitudinally disposed within the heat pipe interconnecting the evaporator and the condenser sections. The evaporator section is placed on the electronic device and the condenser section is enclosed in a housing which is connected to a heat sink. In operation, the electronic device generates heat energy which causes the fluid in the evaporator to vaporize building a vapor pressure in the heat pipe. The heat pipe expands in the direction of the condenser causing the condenser section to make intimate contact with the inside of the housing. The vapors condense at the condenser section and are brought back to the evaporator section via the circumferential wick, the walls of the bellows vessel and the wick slab.

76 citations


Journal ArticleDOI
TL;DR: The thermal performance of a rectangular thermosyphon loop was studied in this article, using a one-dimensional approximation, the convectional friction factor, and an empirical correlation for the overall heat transfer in the cooler, was shown to predict accurately the loop performance at steady state or approaching steady state, if the effective length was used to replace the geometeric length in the calculation of loop friction.
Abstract: The thermal performance of a rectangular thermosyphon loop was studied. The analysis, using a one-dimensional approximation, the convectional friction factor, and an empirical correlation for the overall heat transfer in the cooler, was shown to be able to predict accurately the loop performance at steady state or approaching steady state, if the effective length was used to replace the geometeric length in the calculation of loop friction. The steady-state natural circulation flow solution obtained was shown to be a function of a dimensionless group PY or (NuGr/Pr) Y and agrees very well with the experimental results.

59 citations


Patent
20 Jun 1988
TL;DR: A thermal management system for a spacecraft includes a plurality of T-shaped pallets each having a radiator panel and mounting panel as discussed by the authors, and each pallet inclues L-shaped internal heat pipes contacting the closed-loop heat pipe and the mounting panel.
Abstract: A thermal management system for a spacecraft includes a plurality of T-shaped pallets each having a radiator panel and mounting panel. The radiator panels are connected end to end to enclose an interior space including the mounting panels. The mounting panels have electronic equipment mounted thereon. L-shaped external heat pipes contact both the mounting panel and radiator panel of each pallet to provide heat transfer from the electronic equipment to the radiator panel when the radiator panel is facing away from the sun. In order to cool the electronic equipment mounted on a pallet facing the sun, a closed-loop heat pipe is disposed in the interior space and each pallet inclues L-shaped internal heat pipes contacting the closed-loop heat pipe and the mounting panel. Heat generated in the electronic equipment of the pallet facing the sun is transferred to the internal heat pipes via the mounting panel and then to the closed-loop heat pipe. The heat then is transferred to the radiator panels facing away from the sun via the closed-loop heat pipe, the internal heat pipes, the mounting panels, and the external heat pipes. In one embodiment, the mounting panels are comprised of a pair of spaced-apart mounting plates, and the legs of the external and internal L-shaped heat pipes contacting the mounting panel are disposed within this space separating the mounting plates.

53 citations


Patent
11 Mar 1988
TL;DR: In this article, a corrugated heat pipe sealed at both ends with a rope-like tension member is disclosed, having a longitudinally corrugation peripheral wall and containing operating liquid therein.
Abstract: A corrugated heat pipe sealed at both ends is disclosed, having a longitudinally corrugated peripheral wall and containing operating liquid therein. The corrugated heat pipe comprises inside a rope-like tension member extending therethrough in its longitudinal direction and secured at both ends. The rope-like tension member has the effect of preventing the corrugated heat pipe from elongation due to the weight thereof when the pipe is inserted in the ground, thus eliminating the possibility of local flattening of the corrugated outer periphery or of breakage of the pipe. Further, even when the coefficient of thermal expansion of the rope-like tension member differs from that of the corrugated heat pipe, since the corrugated heat pipe has its outer periphery corrugated in a wavy form in the longitudinal direction, it can sufficiently absorb the thermal expansion of the rope-like tension member. Thus, the corrugated heat pipe will not be broken, even when the coefficient of thermal expansion of the corrugated heat pipe differs from that of the rope-like tension member.

51 citations


Patent
05 Aug 1988
TL;DR: In this article, a thermal coupling is proposed to promote heat transfer between a heat source and a heat sink with abutting surfaces using a deposition of a thermally conductive substance having a melting point temperature less than the temperature of the heat source.
Abstract: The invention is a thermal coupling to promote heat transfer between a heat source and a heat sink with abutting surfaces using a deposition of a thermally conductive substance having a melting point temperature less than the temperature of the heat source such that the substance when heated will be in a liquid state capable of effectively transferring heat between the heat source and the heat sink. The deposition is situated between and contacts the abutting surfaces of the heat source and the heat sink. The substance is contained using a sealant to completely enclose the substance between the heat source and heat sink surface while an adhesive is used to secure the heat source to the heat sink.

48 citations


Patent
09 Dec 1988
TL;DR: In this paper, a wick layer is attached and fixed to one surface of a metal tape without forming a gap with the metal surface, and thereafter, the tape is rolled so that the surface having the wick layers serves as an inner surface, thus forming a pipe shape, then the pipe wall is corrugated.
Abstract: A wick layer is attached and fixed to one surface of a metal tape without forming a gap with the metal surface, and thereafter, the tape is rolled so that the surface having the wick layer serves as an inner surface, thus forming a pipe shape, then the pipe wall is corrugated. According to the above process, the wick layer is completely and uniformly attached to the inner surface of the heat pipe.

Journal ArticleDOI
TL;DR: A prototype of a sodium heat pipe reactor for steam reforming processes has been developed and tested at energy levels up to 6 kW as discussed by the authors, where both experimental and model simulation data were obtained.
Abstract: A prototype of a sodium heat pipe reactor for steam reforming processes has been developed and tested at energy levels up to 6 kW. Both experimental and model simulation data were obtained. Temperature profiles at nonflow and nonreaction flow conditions were used to adjust the parameters of the model, along with an intrinsic rate equation measured in a differential, bench-scale apparatus. Very good agreement between experiment and model was found for approximately 50 runs under steady state reaction conditions covering a range of process variables. Advantages of the heat pipe as a reactor energy source were confirmed. These include isothermal wall temperatures, energy flux transformation, adjusted flux profiles, and rapid startup. These measurements and computations have provided a model from which optimized configurations have been determined.

Patent
24 Oct 1988
TL;DR: In this paper, a new method for making a sintered metal heat pipe wick is practiced by mixing nickel powder into a slurry with a viscous binder comprising water, which is then injected inside a rotating stainless steel cylindrical heat pipe container, or pipe.
Abstract: A new method for making a sintered metal heat pipe wick is practiced by mixing nickel powder into a slurry with a viscous binder comprising water. Polyox and Methocel. The mixture is then injected inside a rotating stainless steel cylindrical heat pipe container, or pipe, to completely coat the inside surface of the pipe. The rotational rate of the pipe is then increased to force the slurry to level out to a uniform depth set by the thickness of sleeves attached at each end of the pipe. Forced air is then blown through the inside of the rotating pipe to dry the slurry and form a green wick. After stopping rotation of the pipe, it is then heated inside a sintering oven in a reducing atmosphere to disintegrate the binder and leave a sintered metal final composition of the wick. Thus produced wicks prevent "hot spots" because they have a more uniform thickness and are attached more evenly and securely than prior art heat pipe wicks to the inside walls of the heat pipe container.

Patent
14 Dec 1988
TL;DR: In this article, a heat pipe type cooling apparatus for a semiconductor, consisting of a plurality of first copper pipes, each of the first pipes having V-shaped grooves formed in an inner surface thereof and arranged in a circumferential direction thereof, is described.
Abstract: A heat pipe type cooling apparatus for a semiconductor, comprises a plurality of first copper pipes, each of the first pipes having a plurality of V-shaped grooves formed in an inner surface thereof and arranged in a circumferential direction thereof, and a plurality of second copper pipes, each of the second pipes having a plurality of second grooves formed in an inner surface thereof, each of the second grooves having an opening narrower than an inner part thereof. A plurality of ceramic pipes connect the first pipes and the second pipes, through intermediate pipes made of a nickel-iron alloy. One end of each of the second pipes is inserted in a metal block on which a semiconductor is mounted.

Patent
04 Feb 1988
TL;DR: In this paper, an air conditioning system for buildings includes a plurality of air conditioners on the different floors, a cooling gravity type heat pipe connecting vaporizers in the air conditioner with a cold thermal source installed at the top of the building and a warming gravity type Heat pipe connecting a condenser of the air conditioning with a hot thermal source in the basement.
Abstract: An air conditioning system for buildings includes a plurality of air conditioners on the different floors, a cooling gravity type heat pipe connecting vaporizers in the air conditioners with a cold thermal source installed at the top of the building and a warming gravity type heat pipe connecting a condenser of the air conditioners with a hot thermal source installed in the basement of the building. The heat pipes are, respectively, provided with flow control valves at the inlet of each vaporizer and the outlet of each condenser. Each air conditioner is provided with a thermistor for detecting the temperature of the returning air and a liquid level detection switch for detecting the liquid level of the thermal medium in the vaporizer. The flow control valves are respectively controlled based on the detection signals issued by the thermistor and the liquid level detection switch.

Journal ArticleDOI
TL;DR: In this article, a simplified version of this problem has been analyzed in semianalytical form for radial geometry, and the solution is compared to the analogous solution for a linear heat pipe.

Patent
29 Aug 1988
TL;DR: In this paper, a reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other, each pipe being embedded within a carbon-carbon composite structure, which is employed to fabricate a hypersonic vehicle leading edge and nose cap.
Abstract: A reusable, durable heat pipe which is capable of operating at temperatures up to about 3000° F. in an oxidizing environment and at temperatures above 3000° F. in an inert or vacuum environment is produced by embedding a refractory metal pipe within a carbon-carbon composite structure. A reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other, each refractory-metal pipe being embedded within a carbon-carbon composite structure. The reusable, durable, heat-pipe panel is employed to fabricate a hypersonic vehicle leading edge and nose cap.

Patent
19 Dec 1988
TL;DR: In this article, an elongated closed-ended heat pipe with an outer conductive layer with a coating of a fluid absorbing material positioned therein and forming a passage therethrough, and a heat transfer fluid positioned in the heat pipe and absorbed by the absorbent material, the absorbed fluid adjacent to the laser medium heating when exposed to the heat generated in the laser Medium whereby the fluid moves through the heatpipe to a remote location for conduction of the heat therein into the heat sink.
Abstract: In a laser device having a laser medium and a laser pumping device associated therewith the improvement including an apparatus for efficiently dissipating heat generated in the laser medium to maintain the laser medium at a more suitable operating temperature, the apparatus including an elongated closed ended heat pipe having a first portion in closely spaced proximity and in heat conductive relationship to the laser medium and a second remote end portion in heat conductive relationship to a heat sink, the heat pipe having an outer conductive layer with a coating of a fluid absorbing material positioned therein and forming a passage therethrough, and a heat transfer fluid positioned in the heat pipe and absorbed by the absorbent material, the absorbed fluid adjacent to the laser medium heating when exposed to the heat generated in the laser medium whereby the fluid moves through the heat pipe to a remote location for conduction of the heat therein into the heat sink.

Patent
08 Nov 1988
TL;DR: In this paper, a heat pipe system particularly adapted for use with finned evaporators is described, and a separate liquid working fluid return conduit is provided which communicates with a liquid working liquid distribution means for distributing working fluid uniformly to all of the evaporator fins.
Abstract: A heat pipe system particularly adapted for use with finned evaporators (12). In accordance with this invention, a separate liquid working fluid return conduit (20) is provided which communicates with a liquid working fluid distribution means (24) for distributing working fluid uniformly to all of the evaporator fins. Means are also provided in accor­dance with this invention for storing excess liquid working fluid either as a column of liquid within the liquid return pipe which is developed by a flow restrictor (44), or by selecting a distribution wick from a material having low capillary pressure which enables it to become saturated with liquid working fluid.


Patent
Yoshiro Miyazaki1
10 Nov 1988
TL;DR: In this article, a two-phase fluid loop type comprising a liquid duct as a main loop for circulating a working fluid in liquid phase by a pump, an evaporator having a first capillary structure to which the working fluid is supplied from high pressure side of the main loop, a condenser having a second capillary Structure for returning liquid condensate to the low pressure side after radiating heat in the condenser, and a bypass pipe connected between the evaporator and the radiator for transporting vapor evaporated in the vapor through its capillary structures to the second of the
Abstract: A heat-pipe system of the two-phase fluid loop type comprising a liquid duct as a main loop for circulating a working fluid in liquid phase by a pump, an evaporator having a first capillary structure to which the working fluid is supplied from high pressure side of the main loop, a condenser having a second capillary structure for returning liquid condensate to the low pressure side of the man loop after radiating heat in the condenser, and a bypass pipe connected between the evaporator and the radiator for transporting vapor evaporated in the evaporator through its capillary structure to the second capillary of the condenser. With this construction, since the working fluid is circulated by the pump while the supply of the liquid corresponding to that evaporated in the capillary structure of the evaporator is carried out by the capillary force in the evaporator, a large amount of heat can be transported over long distances. A method of and apparatus for controlling a flow rate of a working fluid in a liquid duct of the heat-pipe system is also disclosed.

Patent
24 Oct 1988
TL;DR: In this article, a new method for making a heat pipe wick and arteries includes drilling radial holes around the circumference of the heat pipe container at its ends and stringing monofilament polymer lines inside the container between corresponding holes.
Abstract: A new method for making a heat pipe wick and arteries includes drilling. Radial holes around the circumference of the heat pipe container at its ends and stringing monofilament polymer lines inside the container between corresponding holes. The container is rotated at a slow rate while a slurry of nickel powder mixed into a viscous binder of water, Polyox and Methocel is injected inside the container to cover the inside surface of the container and the lines. The rotational rate of the container is then increased to force the slurry to level out to an uniform depth set by the thickness of sleeves attached at each end of the container. Forced air is blown through the inside of the rotating pipe to dry the slurry and form a green wick. After stopping rotation of the pipe, it is then heated inside a sintering oven in a reducing atmosphere to disintegrate the binder and polymer lines and to leave a sintered metal wick having hollow longitudinal arteries.

Patent
14 Jun 1988
TL;DR: In this paper, a transducer device is used to measure the temperature inside an oven by having plates providing heat absorbent and heat reflective surfaces (2,4) and a thermocouple for measuring the temperature difference between them as a measure of radiant heat.
Abstract: Thermal conditions inside an oven are measured by a transducer device (1) having plates providing heat absorbent and heat reflective surfaces (2,4) and a thermocouple for measuring the temperature difference between them as a measure of radiant heat. The plates are mounted on a thin thermally insulating layer secured to a heat sink in the form of a copper mass (7,9), and a second thermocouple measures the temperature difference between the heat absorbent surface and the heat sink as a measure of heat flux through the surface. A Peltier cooler (55) or a flowing liquid can be used alternatively as a heat sink. Heat flux alone can be measured by omission of the heat reflective surface, and where the heat sink is a flowing fluid the heat gained can be measured.

Patent
03 Nov 1988
TL;DR: In this paper, a dual-tube heat pipe type heat exchanger comprising a heat pipe confined with a working fluid for transferring a heat as a latent heat by repeating evaporations and condensations is described.
Abstract: Herein disclosed is a dual-tube heat pipe type heat exchanger comprising a heat pipe confined with a working fluid for transferring a heat as a latent heat by repeating evaporations and condensations. The heat pipe includes an outer tube which is disposed within a hot fluid such that its axis is generally horizontal. Further included is an inner tube which is inserted in the outer tube and radially offset upward to substantially contact with the top portion of the inner face of the outer tube and to confine a space between the inner circumference of the outer tube and the outer circumference of the inner tube, thus forming the heat pipe.

Patent
15 Nov 1988
TL;DR: In this paper, a liquid supply control is disclosed for a heat transfer system which transports heat by liquid-vapor phase change of a working fluid, where an assembly (10) of monogroove heat pipe legs (15) can be operated automatically as either heat acquisition devices or heat discharge sources.
Abstract: A liquid supply control is disclosed for a heat transfer system which transports heat by liquid-vapor phase change of a working fluid. An assembly (10) of monogroove heat pipe legs (15) can be operated automatically as either heat acquisition devices or heat discharge sources. The liquid channels (27) of the heat pipe legs (15) are connected to a reservoir (35) which is filled and drained by respective filling and draining valves (30, 32). Information from liquid level sensors (50, 51) on the reservoir (35) is combined (60) with temperature information (55) from the liquid heat exchanger (12) and temperature information (56) from the assembly vapor conduit (42) to regulate filling and draining of the reservoir (35), so that the reservoir (35) in turn serves the liquid supply/drain needs of the heat pipe legs (15), on demand, by passive capillary action (20, 28).

01 Nov 1988
TL;DR: A steady-state heat pipe analysis program, HTPIPE as mentioned in this paper, was developed at Los Alamos National Laboratory to evaluate the performance limits of a heat pipe at a specified evaporator exit temperature.
Abstract: A steady-state heat pipe analysis program, HTPIPE, operational on CRAY computers, is documented. HTPIPE has two input/output (I/O) options: pressure and temperature profiles along the heat pipe, and calculation of performance limits. Pressure and temperature profiles are calculated based on user-specified boundary conditions, which may be any two of the following: power throughput, evaporator exit temperature, source temperature, and sink temperature. The performance limits represent the maximum heat transport limits at a specified evaporator exit temperature. The calculated performance limits are the capillary, viscous, sonic, entrainment, and boiling limits. User input is interactive, with the available option of parametric variation during a single program execution to facilitate heat pipe design optimization. The hydrodynamic model is described. Program I/O is detailed and supplemented with examples. A program listing and a flow chart are included in this manual. HTPIPE is consistent with the theories and correlations used for heat pipe design at Los Alamos National Laboratory to date. 13 refs., 2 figs., 3 tabs.

Journal ArticleDOI
TL;DR: In this article, a 25kW sodium heat pipe reforming reactor has been constructed and tested as a possible device for solar integrated receivers in thermochemical processes, and the prototype was a 2.3m heat pipe, 5.1 cm in diameter, with a condensing section 1.83 m long inserted concentrically into a 15.2 cm reactor.

Journal ArticleDOI
TL;DR: In this article, velocity and temperature profiles were measured at the entrance and exit to the heating section of a toroidal thermosyphon loop operating under steady flow conditions for a range of heat inputs.
Abstract: Velocity and temperature profiles were measured at the entrance and exit to the heating section of a toroidal thermosyphon loop operating under steady flow conditions for a range of heat inputs. Velocity measurements were made with a laser-Doppler velocimeter and temperature measurements with a small thermocouple probe. Detailed results are presented for the longitudinal and circumferential components of the velocity for four heat inputs. The data for cross-stream secondary flows and streamwise flow reversals emphasize the importance of including three-dimensional effects in analyses of these systems.

Patent
18 Feb 1988
TL;DR: In this paper, an improved heat pipe with an external artery is presented, where the longitudinal slot in the heat pipe wall is filled with sintered wick material and the wall of the external artery wall is also covered with Sintered Wick material.
Abstract: An improved heat pipe with an external artery. The longitudinal slot in the heat pipe wall which interconnects the heat pipe vapor space with the external artery is completely filled with sintered wick material and the wall of the external artery is also covered with sintered wick material. This added wick structure assures that the external artery will continue to feed liquid to the heat pipe evaporator even if a vapor bubble forms within and would otherwise block the liquid transport function of the external artery.

Journal ArticleDOI
TL;DR: In this paper, a closed two-phase thermosyphon operating with Refrigerant-11 and with imposed convection boundary conditions at the heated and cooled surfaces is experimentally investigated and analytically modeled with a lumped parameter model for varying working fluid temperatures.