Showing papers on "Heat pipe published in 1986"

Capillary-pumped heat transfer panel and system

Abstract: A thermal management system using heat pipe principles and incorporating capillary-pumped equipment mounting panels such that a heat transport loop without moving parts is provided. The panels can function to either absorb heat or to reject heat and can interface with heat generating equipment or heat radiators. Each panel comprises a pair of coextensive flat plates bonded together with a thin, fine-pore sheet wick interposed therebetween. A network of liquid grooves in one plate is in fluid communication with the sheet wick which covers the grooves and most of the plate and a separate liquid line connecting the panels. A network of vapor channels in the other plate is in fluid communication with the wick and with a separate vapor line connecting the panels. The vapor channel networks of the panels and the liquid groove networks of the panels are connected such that the panels are arranged in parallel in the fluid circuit or loop. A heat input into panels in the loop causes evaporation of liquid off the surface of the sheet wick. Vapor from the evaporated liquid is circulated to panels serving as cold sinks where the vapor is condensed. Capillary action of the wicks returns the condensate to the panels being heated where the cycle is repeated.

Polymeric heat pipe wick

Abstract: A wick for use in a capillary loop pump heat pipe. The wick material is an essentially uniformly porous, permeable, open-cell, polyethylene thermoplastic foam having an ultra high average molecular weight of from approximately 1,000,000 to 5,000,000, and an average pore size of about 10 to 12 microns. A representative material having these characteristics is POREX UF which has an average molecular weight of about 3,000,000. This material is fully compatible with the FREONs and anhydrous ammonia and allows for the use of these very efficient working fluids in capillary loops.

Dual bed heat pump

Abstract: A heat pump method and system with a pair of solid adsorbent beds (12 and 14) connected to a heat pump loop (10) and a reversible heat transfer loop (11). The heat transfer loop has a heater (24) connected between one end of the beds and a cooling heat exchange (25) connects the other end of the beds so that a heat transfer fluid flowing around the heat transfer loop heats one bed and cools the other.

Solid-state electrocaloric cooling system and method

Abstract: A solid-state system and method for extracting heat from a given load which includes connecting a first diode heat pipe between an electrocaloric heating and cooling element and a load and a second diode heat pipe between the electrocaloric heating and cooling element and a heat sink. By appropriately pulsing the electrocaloric element to provide continuous heating and cooling thereof, heat may be continuously extracted from the load and through the two diode heat pipes to a heat sink.

Effective thermal conductivity of sintered heat pipe wicks

Abstract: The effective thermal conductivity of sintered metal materials similar to those used in heat pipe wicks has been investigated. Experimental tests were conducted using both sintered Nickel 200 and sintered copper powders over a temperature range of 25°C to 100 QC. Data were obtained for samples with several porosities in both dry and water-saturated conditions. The effective thermal conductivity of the sintered materials was found to be a function of the thermal conductivity of the solid material from which the sintered metal was made, the porosity, the mean sample temperature, and whether the material was dry or saturated. The results of the experimental investigation are presented and compared with the experimental results and analytical solutions of other investigators. Nomenclature b = dummy variable c = dummy variable ke = effective thermal conductivity k( = thermal conductivity of the liquid ks = thermal conductivity of the solid r == radius of the contact point R = radius of the powdered particles x = dummy variable a = experimental parameter P =(l-v)/(l+v) g = porosity v =*,/*. pb = bulk density of the sintered material pg = density of the solid material

Vapor flow analysis in a double-walled concentric heat pipe

Abstract: The equation of fluid motion for the steady flow in a double-walled concentric heat pipe with various distributions of evaporation and condensation has been solved numerically. The conditions in the condenser section are decidedly more complex. Reverse flows occur in the condenser section and occupy a substantial fraction of the condenser length for high condensation cooling rates. Pressure drops and hydrodynamic entrance lengths are presented for symmetric and asymmetric cases, and practical results of the calculation of pressure losses for low-speed vapor flows in the double-walled concentric heat pipe are given.

Semiconductor power module with integrated heat pipe

Abstract: A semiconductor power module includes a metallized ceramic carrier plate having an opening formed therein, a semiconductor power component with a base area of a given size adjacent the ceramic plate at the opening, a heat pipe integrated in the semiconductor power module having a vapor space, a condensation zone and a heating zone for distributing heat removed from the semiconductor power component at the heating zone over an area of the condensation zone being larger than the given area, a highly heat-conducting ceramic base plate having two metallized sides, and a frame vacuum-tightly interconnecting the carrier plate and the base plate forming the vapor space of the heat pipe therebetween.

Expandable pulse power spacecraft radiator

Abstract: An expandable heat rejection system for radiating heat generated by a source of heat on a spacecraft or like vehicle is described and comprises a fluid heat exchange medium in operative heat exchange contact with the source for absorbing heat by evaporation of the liquid phase of the medium, a thin flexible wall structure having an inlet and an outlet and defining a volume expandable and collapsible between preselected limits and defining an inner condensation surface and an outer heat radiating surface, a multiplicity of capillary grooves on the condensation surface for promoting condensation of vaporous medium and for facilitating flow of condensate along the condensation surface toward the outlet, and a pump for circulating the medium through the system.

Droplet radiator systems for spacecraft thermal control

Abstract: Liquid-droplet radiators (LDRs) can be as much as 5 to 10 times lighter than advanced heat pipe radiators. They are virtually immune to puncture, stow in a small volume, and are easily deployed. Systems studies show that they optimize in the 10to 100-MW size for liquid lithium, tin, and aluminum and at several hundred kilowatts for NaK and vacuum oils. Larger radiators can be constructed from modules of these sizes. Power systems reoptimized for the light LDR mass operate at 100 K lower reject heat temperatures and may be 3 to 5 times lighter than those using conventional radiators. Recent collector tests have revealed a splash-free regime of operation promising high collection efficiencies. LDR tests in space should be feasible in the near future.

Transient performance investigation of a space power system heat pipe

Abstract: Start-up, shut-down, and peak power tests have been conducted with a molybdenum-lithium heat pipe at temperatures to 1500 K The heat pipe was radiation coupled to a water cooled calorimeter for the tests with rf induction heating used for the input to the evaporator region Maximum power throughput in the tests was 368 kw corresponding to a power density of 23 kw/cm/sup 2/ for the 14 cm diameter vapor space of the annular wick heat pipe The corresponding evaporator flux density was approximately 150 w/cm/sup 2/ over an evaporator length of 40 cm at peak power Condenser length for the tests was approximately 30 m A variable geometry radiation shield was used to vary the load on the heat pipe during the tests Results of the tests showed that liquid depletion in the evaporator region of the heat pipe could occur in shut-down and prevent restart of the heat pipe Changes in surface emissivity of the heat pipe condenser surface were shown to affect the shut-down and re-start limits 12 figs

Thermal printer temperature regulation system

Abstract: A temperature regulator is provided in a thermal printer to maintain reliable and consistent printing quality. The temperature regulator is constructed to either remove heat generated during the printing process from the printing area and/or from the printer itself or to supply heat as needed to maintain a constant temperature. The temperature regulator is formed of a heat pipe and a thermoelectric transducer with a common controller.

Apparatus for preventing freeze-up of a pressure regulator valve in a liquified petroleum fuel system

Abstract: An apparatus for preventing freeze-up of a pressure regulator valve in a liquified petroleum fuel system by heating the valve, a fuel expansion chamber and the fuel, after it has been expanded to a gaseous state, to counteract the refrigeration action produced by expansion of the gas at atmospheric pressure A heat pipe transfers heat from an internal combustion engine to the fuel expansion chamber, regulator valve and fuel The fuel is heated to a selected temperature in the range of 80° F to 140° F The heat pipe can provide structural support to the fuel expansion chamber to facilitate the installation of the fuel conversion system The heat pipe can comprise a metal pipe or a corrugated metal hose which allows relative movement between the condenser and the evaporator ends of the pipe Additionally, a heat pipe using a porous wick can be used so that the fuel expansion chamber can be located below the attachment point of the evaporator portion of the heat pipe to the engine

Functional and performance tests of two capillary pumped loop engineering models

Abstract: This paper presents the results of the functional and performance tests for two capillary pumped loop (CPL) engineering models. Both CPL systems are aluminum/ammonia transport systems which contain eight parallel evaporators and six parallel condensers in a single loop. Tests conducted include the transport limit, heat load shearing between evaporators, liquid inventory/temperature control by the reservoir, pressure priming under heat load, diode function of condensers, and isolation of a single deprimed evaporator. Consistent performance results were obtained for both systems. Transport capabilities of up to 70 kw-m with individual evaporators managing up to 1.7 kw, with a corresponding input heat flux of 15w/sq cm, were demonstrated. These tests demonstrated the ability of a CPL system to operate over a wide range of conditions and thus established the viability of these systems for high power thermal management of large spacecraft, such as the NASA Space Station.

Liquid crystal projector with cooling system

Abstract: A liquid crystal display device for enlarging and projecting an image displayed on a transmission liquid crystal display panel through a projecting lens onto a screen by radiating a light from a light source to the panel, has a heat pipe inserted into a transparent cooling vessel filled with transparent cooling liquid for externally radiating heat absorbed by the liquid to suppress the temperature rise of the panel due to the light incident to the panel.

Monogroove cold plate

Abstract: The coolant fluid evaporated in a compact heat absorbing panel (12) utilizing monogroove heat pipes in a pumped two-phase system is replenished through a liquid inlet control valve (35) under the control of an ultrasonic liquid presence detector (40) which is connected to the panel (10). The detector (40) maintains the desired liquid quantity in the panel's liquid coolant channels (25), thereby dynamically responding to varying heat loads.

Detailed transient model of a liquid-metal heat pipe

Abstract: A detailed transient model of a liquid-metal heat pipe is being developed. The model includes start from the frozen state, with provision for free-molecule flow, and proceeds through the steady-state operating conditions. The KACHINA method has been selected for simulating the compressible flow in the core; the SIMPLER method, for simulating the liquid flow in the wicks and grooves. The computational methods have been demonstrated on a Compaq Deskpro II. The FORTRAN cove is currently being converted to the IBM 3033 and Cray I. Based on the ratio of Cray to Compaq speeds, the Cray computation times are estimated to be 30 minutes per hour simulated.

Inert anode stable cathode assembly

Abstract: This invention includes apparatus and method for providing a support mechanism for electrode assemblies including positioning spacer of electrically nonconductive material having an inside surface forming an internal cavity and a heat pipe for passing a heat transfer fluid through the cavity along the inside surface. The heat pipe transfers heat away from the positioning spacer to form a protective layer of frozen bath around the positioning spacer.

Method and apparatuses for heat transfer

Abstract: A system for controlling the flow of thermal flux including a heat source and a heat sink being in proximity to each other and an electrochemically variable thermal switch to control transfer of heat therebetween.

Heat pipe array heat exchanger

Abstract: A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

Chemical heat pipe employing self-driven chemical pump based on a molar increase

Abstract: A chemical pump system that utilizes a self-driven compressor to increase the system pressure while obviating the need for a one-way valve and liquid head to provide the driving force for the reactants, thus enhancing long distance transport. The system comprises a chemical heat pipe employing reversible endothermic/exothermic chemical reactions to transfer thermal energy between a heat source and a heat sink. At least one reactant is self-driven substantially unidirectionally through the heat pipe by compressing the reactant(s) with a compressor and heating the reactant(s) to a predetermined pressure and temperature sufficient to form a reaction product having at least a 150% molar increase. The reaction product is expanded with an expander that is linked mechanically to the compressor. The expansion energy is sufficient to compress the reactants to the predetermined pressure while maintaining the self-driven unidirectional flow.

Method and apparatus for evacuating and filling heat pipes and similar closed vessels

Abstract: A table carries guides for receiving and guiding a heat pipe. The heat pipe has a fill port which contains a valve. The heat pipe is thrust against the seal face of a block for evacuating and filling the fluid chamber of the heat pipe. A hex driver passes through the block and engages the valve to open and close the valve while the fill port is sealed from the atmosphere.

Apparatus and method for treating air from a turbocharger

Abstract: Heat exchanger apparatus and method for cooling and removing moisture from air passing from a turbocharger (10) and the like to an intake of a combustion engine (11) is illustrated wherein heat pipes (B) extend across a flow path of the compressed air to a zone (C) of ambient air external of the flow path of compressed air to transfer heat to a controlled ambient air flow in the ambient zone (C) passing across the heat tubes, and including a coalescer zone (D) for collecting and removing moisture from the cooled air.

Heat pipe of aluminum, steel or gray cast iron

Abstract: A heat pipe of aluminum is provided on the inside on all sides thereof with a completely closed fluid-tight coating of a water-resistant nickel in order to make the same resistant against water as heat carrier medium or to make the same vacuum-tight for long periods of time. Also, a coating of hard solder material is possible. The coating thickness is no less than 10 μm and no more than 15 μm. Individual parts of the heat pipe, prior to the soldering, are coated with the nickel material, each by itself, completely up to the joint areas. A process of making the heat pipe is also provided.

Hair styler having a heat pipe forming the hair winding portion

Abstract: A hair styler for winding hair thereon for curling, comprising a hollow sealed tubular member made of a metallic material having good thermal conductivity and defining a heat pipe having a heat dissipating hair winding portion. The tubular member contains a charge of a working fluid vaporizable at an operating temperature of 50° C. to 70° C. The outer surface of the heat dissipating portion of the heat pipe is covered with an elastic hair engagement member for preventing hair slippage. The heat receiving end portion of the heat pipe is exposed so as to be adapted to receive heat from a separate external heat source having a temperature range of 50° C. to 120° C. Thereby hair wound around the outer surface of the heat dissipating portion of the heat pipe forming the bobbin is heated by the condensation of the vaporized working fluid within the heat pipe.

Method for heating a road by means of geothermally fed heating installation as well as a road-heating installation for carrying out the method

Abstract: A road heating installation which is supplied by heat stored in the ground and which includes heat pipes placed heat-conductingly with the road surface, is provided with sensors for detecting the climate factors relevant for the road condition and is equipped with a control apparatus that controls the heating installation as a function of the climate. In order to remove the heat energy stored in the ground only in case of need and to avoid the unnecessary exhaustion thereof, the invention provides that the heat transfer capacity of the heat pipe is controllable by a reversible blocking of the condensation zones of the heat pipes and the blocking is brought about in case of a dry-cold by the supply of an inert gas into the condensation zones of the heat pipes which is quantity-regulatable directly from the outside.

Thermally stabilized laser cavity

Abstract: A support structure for a gas laser cavity in which the longitudinal support members are constructed as identical heat pipes with a common thermal interconnection. With this common thermal system, thermal effects and, therefore, thermal expansions are equalized for all members and the laser cavity maintains alignment despite changes in operating temperatures.