Showing papers on "Heat pipe published in 2001"
TL;DR: In this article, a closed-loop pulsating heat pipe (PHP) was analyzed using a charge coupled device (CCD) and the authors observed that during the start-up period, the working fluid oscillates with large amplitude, however, at steady operating state, the fluid circulates.
252 citations
Patent•
02 Jul 2001TL;DR: Bipolar electrosurgical forceps as mentioned in this paper include a first electrode attached to a first heat pipe and a second electrode connected to a second heat pipe. The heat pipe can be removably attached to the forceps.
Abstract: Bipolar electrosurgical forceps includes a first electrode attached to a first heat pipe and a second electrode attached to a second heat pipe. The heat pipe can be removably attached to the forceps. The forceps can also include a securing mechanism that secures the removable heat pipes to the device.
217 citations
Patent•
07 Mar 2001TL;DR: Light Emitting Diode Light Sources for Dental Curing are described in this paper, where some embodiments of the invention include structures such as light emitting diode array(s), heat sink, heat dissipation, heat pipe, and control circuitry.
Abstract: Light Emitting Diode Light Sources for Dental Curing are disclosed. Some embodiments of the invention include structures such as Light Emitting Diode Array(s), heat sink, heat dissipation, heat pipe, and control circuitry are disclosed.
162 citations
TL;DR: In this paper, the authors investigated the potential application of heat pipes and phase change materials for thermoelectric refrigeration and found that the heat pipe units employing heat pipe embedded fins were well suited to this application.
123 citations
TL;DR: In this paper, an advanced heat pipe mechanism that has the potential of achieving heat flux capabilities over 250 W/cm/sup 2 was discussed, which utilizes thermally driven pulsating two-phase flow to achieve high heat flux capability and heat transfer coefficient.
Abstract: This paper discusses an advanced heat pipe mechanism that has the potential of achieving heat flux capabilities over 250 W/cm/sup 2/. The mechanism utilizes thermally driven pulsating two-phase flow to achieve high heat flux capability and heat transfer coefficient. A simplified hydrodynamic model in was developed to guide the proof-of-concept heat pipe design. A more detailed numerical model was also developed and will be solved to predict the heat pipe's thermal performance. Test results of proof-of-concept heat pipes verified the heat flux capability of the advanced mechanism and the accuracy of the simplified model. Pulsating heat pipes are feasible approaches to removing increasing heat dissipation densities in electronic equipment.
108 citations
TL;DR: In this article, a working prototype of a latent heat storage system for night-time cooling of buildings has been presented, and the design, construction and testing of the prototype is reported, including measurements of heat transfer rates.
100 citations
TL;DR: In this paper, the authors describe the flow of convective heat currents through two identical tree networks superimposed, and oriented in counterflow, and show that the total heat current convected by the double tree is proportional to the total volume raised to power 3/4.
100 citations
Patent•
[...]
TL;DR: In this paper, the inner peripheral grooves for transporting a liquid of a working fluid in the longitudinal direction of a first wick are provided along the first Wick which transports the liquid contained in the evaporator to a heating portion by capillary force, and a liquid supply portion for supplying the liquid of the working fluid is further provided to the inner peripherals.
Abstract: Inner peripheral grooves for transporting a liquid of a working fluid in the longitudinal direction of a first wick are provided along the first wick which transports the liquid contained in the evaporator to a heating portion in the evaporator by capillary force, and a liquid supply portion for supplying the liquid of the working fluid is further provided to the inner peripheral grooves. Therefore, the liquid of the working fluid can be efficiently supplied to the inner peripheral surface of the first wick with a simple structure, so that a loop type heat pipe which can be constantly stably operated can be obtained.
86 citations
Patent•
03 Oct 2001
TL;DR: In this article, a heat pipe heat exchange catheter is used to produce hypothermia in a selective area of the body without cooling the entire body system, which is of particular advantage in brain surgeries where stroke, trauma or cryogenic tumors can best be addressed under hypothermic conditions.
Abstract: A catheter is adapted to exchange heat with a body fluid, such as blood, flowing in a body conduit, such as a blood vessel. The catheter includes a shaft with a heat exchange region disposed at its distal end. This region may include at least one balloon which is adapted to receive a remotely cooled heat exchange fluid preferably flowing in a direction counter to that of the body fluid. Embodiments including multiple balloons enhance the surface area of contact, and the mixing of both the heat exchange and the body fluid. The catheter can be positioned to produce hypothermia in a selective area of the body without cooling the entire body system. It is of particular advantage in brain surgeries where stroke, trauma or cryogenic tumors can best be addressed under hypothermic conditions. Heat pipe technology can be used to form a heat pipe heat exchange catheter. The heat pipe heat exchange catheter includes metallic bellows which allow for flexibility. The temperature control source can be portable to enable the heat pipe heat exchange catheter to be used in the ambulatory environment.
73 citations
Patent•
20 Mar 2001TL;DR: In this article, a heat transfer device for a mobile computer system using a loop heat pipe coupled to the processor die is presented, where the vapor space and liquid space are separated.
Abstract: A heat transfer device for a mobile computer system using a loop heat pipe, the evaporator of the loop heat pipe coupled to the processor die. The vapor space and liquid space are separated. The separation of the vapor space, and the wick structure of the liquid space, ensures that the vapor space will not be distorted or clogged by the wick structure. The heat transfer device can be bent to meet design criteria without distorting the width or radius of the vapor space. In one embodiment of the present invention the evaporator, condenser, and liquid space have different types of wick structure. Another embodiment of the present invention, the vapor space of the loop heat pipe has uniform thickness. The loop heat pipe device of the present invention provides reduced evaporator and condenser resistance and increased burn out flux, thereby increasing the power handling capacity of the device.
71 citations
01 Jan 2001
TL;DR: An experimental investigation of the influence of system pressure on the Boiling Heat Transfer Coefficient in a closed two-phase Thermosyphon Loop was carried out in this article.
Abstract: An Experimental Investigation of the Influence of System Pressure on the Boiling Heat Transfer Coefficient in a Closed Two-Phase Thermosyphon Loop
04 Apr 2001
TL;DR: In this paper, the authors discuss the temperature oscillation phenomenon using test data from a miniature LHP and show that the loop operating temperature never reaches a true steady state, but instead becomes oscillatory.
Abstract: Loop heat pipes (LHPs) are versatile two-phase heat transfer devices that have gained increasing acceptance for space and terrestrial applications The operating temperature of an LHP is a function of its operating conditions The LHP usually reaches a steady operating temperature for a given heat load and sink temperature The operating temperature will change when the heat load and/or the sink temperature changes, but eventually reaches another steady state in most cases Under certain conditions, however, the loop operating temperature never really reaches a true steady state, but instead becomes oscillatory This paper discusses the temperature oscillation phenomenon using test data from a miniature LHP
TL;DR: In this article, an analytical model is developed to predict evaporation heat transfer performance in a triangular groove formed by trapezoidal fins covered by a thin fine porous layer, which not only improves the capillary force but also extends the evaporating surface.
Patent•
05 Jun 2001
TL;DR: In this paper, a heatpipe type radiator is described, which includes a plurality of fins closely arranged side to side and correspondingly provided with at least one first hole, and at least a heat pipe extended through the fins via the holes provided on each fin.
Abstract: A heat-pipe type radiator includes a plurality of fins closely arranged side to side and correspondingly provided with at least one first hole, and at least one heat pipe extended through the fins via the at least one hole provided on each fin. Each hole on the fin is provided at an edge with a second hole. A bonding agent is applied via the second holes into the first holes to fill up a clearance in the first holes between the heat pipe and the fins. In this type of radiator, an entire circumferential surface of the heat pipe is in contact with the fins to enable enhanced heat transfer from the heat pipe to the fins. In a method of producing the above-described heat-pipe type radiator, the bonding agent may be a solder paste or a solder stick depending on a shape of the second hole and is heated to a melting point to flow from the second holes into the first holes. After the molten bonding agent is cooled and set, it firmly bonds the heat pipe and the fins together.
TL;DR: In this paper, a steady state two-dimensional theoretical analysis of laminar film condensation heat transfer inside the condenser section of inclined wickless heat pipes flat-plate solar collector is presented.
TL;DR: In this article, the authors suggest an innovation of heatpipe system by using new working fluids, which have a positive gradient of surface tension with temperature, to improve the performance of capillary-pumping heatpipe systems and their operative stability.
Patent•
25 Apr 2001
TL;DR: In this article, a well is filled with water and a pipe is placed within the well with a pump at its distal end, the pump draws cold water from within a well into the pipe, out of the well into a heat exchanger where it cools the air which, in turn, cooling the house.
Abstract: The system uses a well drilled deep into the ground and filled with water. The well is encased and sealed at its bottom to prevent the loss of water. The casing of the well is in contact with the surrounding earth for heat conduction. A pipe is placed within the well with a pump at its distal end. The pump draws cold water from within the well into the pipe, out of the well into a heat exchanger where it cools the air which, in turn, cools the house. After the water has gone through the heat exchanger, it is returned to the well. Heat pipes are used to dissipate, in winter, the heat accumulated during the summer cooling months. The heat pipes extend outwardly from near the top of the well and contain a substance that will absorb heat and evaporate at the end in the well and condense and release heat at the opposite end. An upward slant of the heat pipe ensures that this heat transfer occurs only in the direction away from the well.
Patent•
12 Sep 2001TL;DR: In this article, a heat dissipating assembly (1) includes a pair of concertinaed heat pipes (10), a plurality of fins (20), a shell (30), a heat-conductive block (40), and a fan (50).
Abstract: A heat dissipating assembly (1) includes a pair of concertinaed heat pipes (10), a plurality of fins (20), a shell (30), a heat-conductive block (40) and a fan (50). The fins are spaced and stacked one above the other. A plurality of channels (22) is defined through opposite sides of the fins, for insertion of the heat pipes thereinto. The shell includes a frame (32) and a cover (34) mounted to a top side of the frame, thereby defining a space for accommodating the fins and the heat pipes therein. A plurality of openings (362, 342) is defined in a bottom plate (36) of the frame and in the cover, for extension of bottommost and topmost portions of the heat pipes therethrough. A horizontal end portion (12) of each heat pipe extends over the cover and engages with the block. The fan is mounted to one end of the shell.
Patent•
09 Nov 2001TL;DR: In this article, an electronic assembly including a motherboard (12), a semiconductor die (20), and a heat pipe (22) having an evaporator portion (34) adjacent the die n and a condenser portion (36) distant from the die, is described.
Abstract: An electronic assembly (10) is described including a motherboard (12), a semiconductor die (20) mounted to the motherboard (12), and a heat pipe (22) having an evaporator portion (34) adjacent the die n (20), and a condenser portion (36) distant from the die (20). The heat pipe (22) is connected to a ground plane (60) of the motherboard (12) at various locations. Structural integrity of the heat pipe (22) is provided by an insert (142) in an evaporator portion (34) of the heat pipe (22) and because of opposing recessed seat portions (74, 76, 80, 82) that contact one another. Another feature of the electronic assembly (10) is that it has a sheet (90) of material forming a plurality of fins (30) that are welded to a condenser portion (36) of the heat pipe (229).
Patent•
IBM1
TL;DR: In this paper, an apparatus and method to provide heat pipe cooling for semiconductor chips mounted on a module is described, where each chip is provided with its own heat pipe for cooling.
Abstract: An apparatus and method are disclosed to provide heat pipe cooling for semiconductor chips mounted on a module. Each chip is provided its own heat pipe for cooling. A piston on the end of each heat pipe is loaded against each chip with a predetermined force without the need for counting turns of a screw or use of torque measurement tools. Each heat pipe draws heat away from the chip it is loaded against, carrying the heat to a heat sink for dissipation into the ambient. A large multichip module can be loaded against a land grid array interposer with uniform loading of the interposer. This interposer loading is accomplished independently of the loading of the heat pipes against the chips.
TL;DR: In this article, the operation requirements of oscillating heat pipes (OHPs) with nonflammable fluorocarbon fluids, FC-72 and FC-75, as working fluid are developed.
Abstract: Operation requirements of oscillating heat pipes (OHPs) are proposed. Based on the requirements, OHPs with nonflammable fluorocarbon fluids, FC-72 and FC-75, as the working fluid are developed. The OHPs have an inner diameter of 1.75 mm, a total length of 446 mm, and 40 tubing turns. There are two condensers on both outer sides and one evaporator in the middle of the OHPs. Thermal performance tests are conducted at various operating temperatures and heat rates. The working fluid fill ratio is varied. A high-performance OHP with FC-72 has been indicated for the first time. The FC-72 OHP can transport a 2040-W heat rate without dryout. The gravitational acceleration does not have a noticeable influence on the performance of the fluorocarbon OHP. The thermal performances of the fluorocarbon OHPs are compared with the case of an acetone OHP.
Patent•
28 Dec 2001TL;DR: In this paper, a heat processing apparatus comprises a hot plate for putting the substrate on or near its surface, a ceiling with a first and second concentric regions with heat pipes opposite to the hot plate surface, and a gas flow generator supplying gas to the a region from a circumference of the hot plates to a center of the ceiling, and temperature control mechanism for controlling a regional temperature of the first region.
Abstract: A heat processing apparatus comprises a hot plate for putting the substrate on or near its surface, a ceiling with a first and second concentric regions with a first and second heat pipes, respectively, opposite to the hot plate surface, a member surrounding a space between the hot plate and the ceiling, a gas flow generator supplying gas to the a region from a circumference of the hot plate to a center of the ceiling, and a temperature control mechanism for controlling a regional temperature of the first region in such a manner that a heat emission is greater from a center of the substrate than from a circumference of the substrate, thus heating a substrate to a uniform temperature all over its surface
Patent•
26 Sep 2001
TL;DR: In this paper, a system for cooling a canister has first, second and third heat pipes, and a condenser with a plurality of fins on the condenser of the third heat pipe.
Abstract: A system for cooling a canister has first, second and third heat pipes. The first heat pipe has an evaporator and a condenser. The first heat pipe is mounted with its evaporator inside the canister and its condenser outside the canister. The second heat pipe has an evaporator conductively coupled to the condenser of the first heat pipe. The second heat pipe has a condenser. The third heat pipe has an evaporator conductively coupled to the condenser of the second heat pipe. The third heat pipe has a condenser with a plurality of fins on the condenser of the third heat pipe.
TL;DR: In this article, a software for flat miniature heatpipe parameters (Q max, R hp, temperature field along the pipe surface, heat transfer coefficients in the evaporator and condenser zones h e, h c, etc.) prediction and numerical modeling was developed.
Patent•
17 May 2001
TL;DR: In this paper, a notebook computer has a base housing with a heat-generating microprocessor therein, and a lid housing pivotally connected to the base housing, where operating heat from the microprocessor is transferred to the lid housing, for dissipation therefrom, via a specially designed thermosyphoning heat pipe structure formed from first and second heat pipes.
Abstract: A notebook computer has a base housing with a heat-generating microprocessor therein, and a lid housing pivotally connected to the base housing. Operating heat from the microprocessor is transferred to the lid housing, for dissipation therefrom, via a specially designed thermosyphoning heat pipe structure formed from first and second heat pipes. The first heat pipe representatively has a rectangular cross-section, an evaporating portion thermally communicated with the microprocessor, and a coiled condensing portion centered about the lid hinge line and having a circularly cross-sectioned interior side surface portion defined by flat sides of the first heat pipe. The second heat pipe has a circular cross-section, an evaporating portion pivotally received within the coiled first heat pipe portion, and a condensing portion thermally communicated with the lid housing. When the lid housing is opened and closed, the evaporating portion of the second heat pipe is rotated within the coiled first heat pipe portion and slidably engages its circularly cross-sectioned interior side portion.
TL;DR: In this article, the microfilm evaporation and two-phase flow inside the microstructure was used to develop new microscale heat transfer model for boiling heat transfer on porous surfaces.
Patent•
20 Dec 2001TL;DR: In this article, the authors proposed a method to improve the heat radiating performance of an electronic apparatus provided with semiconductor devices which generate heat at a high rate by using a heat pipe.
Abstract: The present invention is intended to improve the heat radiating performance of an electronic apparatus provided with semiconductor devices which generate heat at a high rate. An air passage ( 20 ) is formed in a case 10 , and a fan ( 6 ) produces air currents in the air passage ( 20 ). Heat generated by a heat-generative part ( 1 ) mounted on a circuit board ( 2 ) is transferred to a wall ( 21 ) included in walls defining the air passage ( 20 ) by a heat transfer member ( 3 ), such as a heat pipe, and is carried outside the case 10 by cooling air flowing through the air passage ( 20 ).
TL;DR: In this article, the measured and calculated properties of three collector-based solar cooking systems are described and extensive outdoor measurements were conducted in Marburg (latitude 50.8° N) proving the operational stability of the different heat pipe systems even on days with rapidly varying irradiance.
TL;DR: In this article, a finite difference solution was employed to determine the mean velocity, volumetric flow rate, and Poiseuille number ( Po = fRe ) as functions of the groove aspect ratio, groove-half angle, meniscus contact angle and imposed shear stress at the liquid-vapor interface.