CN101431879A

CN101431879A - Heat pipe intensified electronic device radiator

Info

Publication number: CN101431879A
Application number: CNA2007101243640A
Authority: CN
Inventors: 秦彪
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-11-07
Filing date: 2007-11-07
Publication date: 2009-05-13
Anticipated expiration: 2027-11-07
Also published as: CN101431879B

Abstract

The present invention provides a radiator used in electronic devices, which comprises the following procedures: taking sun-flower style CPU radiator as basic prototype structure; introducing heat pipe; strengthening heat transmission by using high effective heat transmission feature of the heat pipe; adding an outside fin(2) on heat pipe(5) to increase radiating area greatly. Meanwhile, fin efficiency will no be lowered and features of prototype radiator will be preserved. Heat transmission strengthened structure and optimized design make the radiator small and compact. Wind pressure is increased and air flow is enlarged by adopting centrifugal fan or multilevel axial flow fan, and heat dissipating capacity is further improved.

Description

Heat pipe intensified electronic-device radiator

Affiliated technical field

The present invention relates to the heat dissipation technology field of electronic device, particularly by the radiator of forming by heat-conducting block, heat pipe, fin and fan.

Background technology

Power raising along with semiconductor power device, light emitting semiconductor device, the particularly increase of semiconductor integrated circuit number of transistors, and the increase of operating frequency, its caloric value is also along with increase, and current computer CPU and GPU chip cooling problem have become the obstacle in the computer evolution.For a long time, the heat radiation of electronic device gets the brush-off, technology is in the original heat transfer conceptual phase always, last century 60 is to the seventies, the research of heat transfer technology is very perfect, as long as incite somebody to action achievement in research wherein, adopts correct method, introduce the heat dissipation technology of electronic device, just can obtain significant result.

Existing a kind of cpu chip aluminium radiator: an end face of cylinder is a heat-absorbent surface, and it is close on the radiating surface of chip, and fin is in the side of cylinder, adopt aluminum extruded shaping, also be referred to as sun fancy, fan the other end heat-absorbent surface of cylinder back to a side, fan and cylinder are coaxial; The heat that chip produces is by radiating surface on the chip and the heat-absorbent surface thermal contact conductance on the cylinder, pass to cylinder, heat mode with heat conduction in cylinder passes to cylindrical side, pass on the fin again, the fans drive air, the fin of flowing through passes to heat in the air in the convective heat transfer mode and to shed, cylinder only plays conductive force at this, thereby just is referred to as heat-conducting block.This structural advantages has: because fan and cylinder (heat-conducting block) are coaxial, the fans drive air, flow along cylindrical side and fin, the existence in air flows dead band in fin that reduces effectively that fan electromotor causes is conducted heat and have a strong impact on the fin inner air convection.

The radiator of this sun fancy structure when heat dissipation capacity is not high, has its advantage.In case but heat dissipation capacity is when very high, problem will occur, if by the rib that increases fin long (fin root place, by the heat-conducting block place, length to fin point place) strengthen area of dissipation, to cause fin efficiency to descend, the radiator external diameter had been strengthened, and the fin material usage has strengthened, and heat dissipation capacity does not effectively improve; If increase area of dissipation by the rib width (length of heat-conducting block short transverse) that increases fin, can cause that again air flow resistance increases, the air capacity of fin of flowing through reduces, and also has the heat-conducting block height to increase, and this has increased the thermal conduction resistance in the heat-conducting block again, this all will be unfavorable for heat radiation, final result: the radiator height dimension increases, and weight increases, and cost increases, and heat dissipation capacity can not get effective raising, might also can reduce.Thereby explanation, simple sun fancy structure is not suitable for powerful radiator.

This cpu heat that now is used for desktop computer in order to improve heat dissipation capacity, have to increase overall dimensions, and the radiator external diameter reaches 90mm, and rib length and rib width reach 30mm, and purpose increases the fin gross area (area of dissipation) exactly, reaches the raising heat dissipation capacity.Big like this radiator is the device that accounts for the main space size on the computer motherboard, and the space that radiator is shared has become the obstacle that reduces in computer size, the compact design.

Summary of the invention

The present invention carries out significant improvement on the radiator basis of the above-mentioned type, adopt heat pipe to strengthen heat delivered, by on heat pipe, adding fin, add cleverly and arrange, realize increasing fin quantity, reaching the purpose while that increases area of dissipation, do not reduce fin efficiency, keep the advantage of former type again.Introduce the augmentation of heat transfer structure, optimize size, further reduce heat sink size, when reducing material cost, improve heat dissipation capacity again effectively.By centrifugal fan or the multistage axial flow formula fan that adopts high blast, improve air quantity, further improve heat dissipation capacity.

Technical scheme of the present invention is: the main parts of radiator include: heat-conducting block, inner rib plate, outer fin, heat pipe and fan, one smooth heat-absorbent surface is arranged on the heat-conducting block, inner rib plate is arranged on the heat-conducting block side, outer fin is on heat pipe, fan be arranged on heat-absorbent surface back to a side, the invention is characterized in: the evaporation section of heat pipe is arranged on the heat-conducting block, the evaporation section of heat pipe and the heat pipe stage casing bending between the condensation segment, the condensation segment of heat pipe is provided with outer fin, form the air heat exchange unit, being circular arc together, round inner rib plate, is the lengthening of inner rib plate on the rib length direction like outer fin; Round inner rib plate, have two sections air heat exchange units of forming by heat pipe and outer fin that separate at least.

The present invention seems in the fin periphery of existing sun fancy product, has set up one deck fin, so be referred to as outer fin, has kept the advantage of former type products: the existence in air flows dead band in fin of avoiding that fan electromotor causes.The evaporation section of heat pipe by thermal contact conductance, is drawn the heat on the heat-conducting block on heat-conducting block.Because the heat pipe bending radius is restricted, is arranged on the heat pipe evaporator section on the heat-conducting block, and is the heat pipe stage casing of circular arc between the heat pipe condenser section of inner rib plate, must be the circular arc line bending, bending radius should not be lower than the value of regulation.To be heat pipe come from the heat-conducting block transmission heat that passes to outer fin, utilized the efficient heat transfer characteristic of heat pipe, and rib length of outer fin then is by the length of heat pipe condenser section place to rib point place, thereby the interior heat conduction of outer fin is apart from weak point, the fin efficiency height.Illustrate that the present invention under the situation that keeps the high-caliber fin efficiency of entire radiator, has improved the fin area effectively, this will improve heat dissipation capacity widely.

According to thermal conduction study, fin efficiency is the function of mL, descends along with the increase of mL, and mL is 1.0 o'clock, the fin efficiency decrease speed is the fastest, and for straight rib, this moment, fin efficiency was roughly 76%, the value of getting mL during general the design is not more than 1.0, and wherein L is that rib is long, and the square root of the thickness of m and fin is inversely proportional to.If fin thickness reduces 4 times, the long L of rib reduces 2 times, and then fin efficiency is constant.Illustrate to reduce fin thickness, can reduce the fin material usage effectively, fin (aluminium) thickness in the air heat exchanger (evaporator and condenser) in the existing air-conditioning is reduced to below the 0.1mm.Existing product adopts aluminum extruded technology, the thick minimum of rib also has 0.5mm, if adopt other processes that fin is set, with rib is thick when being reduced to as 0.12mm, do not reduce in order to guarantee fin efficiency, rib length will shorten one times, that is to say, have 4 times though the fin material has subtracted, area of dissipation has reduced, and has only original half.If employing the present invention then just can solve this contradiction, realize that material usage significantly reduces, heatsink weight reduces, and heat dissipation capacity does not reduce.

The present invention is limited to rare two sections air heat exchange units of being made up of heat pipe condenser section and outer fin that separate, reason is: if having only one section air heat exchange unit, then the condensation segment length of heat pipe is the whole girth of the circle at condensation segment place basically, and it is oversize that the liquid refrigerant in the heat pipe is back to the average distance of evaporation section; If be divided into two sections, the average distance that then refluxes has reduced half; Also have, when the device radiating surface is vertically placed, adopts two sections air heat exchange units that separate, the liquid refrigerant siphon rising backflow average height in the heat pipe has also reduced half, these all opposite heat tube transmit heat fundamental influence arranged.If liquid refrigerant refluxes apart from too far away, it is highly too high particularly to reflux, and has surpassed the siphon height restriction, and the outer fin away from evaporation section just may lose thermolysis, or effect descends significantly.Air heat exchange unit quantity separately is many more, and liquid refrigerant backflow average distance and siphon backflow average height are just short more, and the obstruction of heat pipe transmission heat is more little, helps giving full play to the effect of outer fin more.

Description of drawings

The present invention is further described below in conjunction with drawings and Examples.

Fig. 1, the 2nd, the basic structure schematic diagram of radiator of the present invention.

Fig. 3,5,6,9, the 10th, the feature structure schematic top plan view of the heat transfer component of forming by inside and outside fin, heat-conducting block and heat pipe in the radiator of the present invention.

Fig. 4 is the feature structure schematic diagram of corrugated fin.

Fig. 7 is the feature structure schematic diagram of nest plate type fin.

Fig. 8, the 11st, the feature structure schematic diagram of stacked fin.

Figure 12 is the feature structure schematic diagram of fork row formula short rib shape augmentation of heat transfer structure.

Figure 13 is the feature structure schematic diagram of venetian blind type short rib shape augmentation of heat transfer structure.

Among the figure, 1, fan, 2, outer fin, 3, inner rib plate, 4, heat-conducting block, 5, heat pipe, 6, the location flanging.

Fig. 1,2 shows basic structure of the present invention and forms, heat-absorbent surface just below heat-conducting block (4), the upside heat-absorbent surface that fan (1) is arranged on heat-conducting block (4) back to a side, inner rib plate (3) is on the side of heat-conducting block (4).The air heat exchange unit of forming by outer fin (2) and heat pipe (5) in inner rib plate (3) periphery, fin (2) outside heat pipe (5) medial and lateral all are provided with, area of dissipation is greatly improved like this.During design, inner rib plate (3) and outer fin (2) are located by fan (1), at grade, making does not have vacant space, overall compact between fan (1) and inner rib plate (3) and the outer fin (2).Heat-conducting block (4) exceeds (axially) inside and outside fin, be to be convenient to circulation of air, the inside and outside fin of flowing through equably, because the electronic device that usually is cooled mostly is flat, or the radiating surface on it is greater than the heat-absorbent surface (cross section) of heat-conducting block, and heat-conducting block exceeds the formed space of fin, just become air flow passage, can eliminate the air flows dead band in the fin like this, these and existing sun fancy cpu heat structure have similar part, have kept the advantage of former type.

For the shared ventilation area of condensation segment and stage casing that reduces heat pipe, increase the area of dissipation of outer fin (2) and inner rib plate (3), flat tube should be adopted in heat pipe (5) condensation segment and stage casing, as shown in Figure 1.Condensation segment adopts flat tube, can also increase effective contact area of outer fin and heat pipe.If single heat pipe required flat, too flat heat control fabrication technique difficulty big, the cost height then can adopt the heat pipe more than two or two to come side by side to substitute.

Fig. 3 shows the vertical view of the heat transfer component of being made up of inside and outside fin and heat-conducting block and heat pipe, employing has two heat pipes, the evaporation section of heat pipe (5) can adopt welding or method for embedding, be arranged on the heat-conducting block (4), these two kinds of methods can effectively solve the contact heat resistance between evaporation section and the heat-conducting block (4).Heat pipe (5) condensation segment and outer fin (2) are circular arc together, near inner rib plate (3), with it round, compact conformation like this.

The bending radius minimum in heat pipe (5) stage casing, attention must not be less than the minimum permissible value of regulation.Heat-conducting block (4) is circular in the Cross-section Design at fin place, also can be designed to ellipse, polygon, but circle is the most reasonable, inner rib plate (3) on the heat-conducting block (4) is to adopt aluminum extruded process forming, whole inner rib plate (3) is extruded together, fuses, and forms monolithic construction.Inner rib plate (3) and heat-conducting block (4) be extrusion molding together, obtains a global facility, removes the part in the fin again, makes heat-conducting block (4) height; Inner rib plate (3) and heat-conducting block (4) also can be divided into two parts, and inner rib plate (3) root is a ring, and all inner rib plates are fused, and the heat-conducting block of core is another part, such as adopting the interference tight fit, are pressed in the ring of inner rib plate root.

Among Fig. 3, fin (2) outside the interior outside of the condensation segment of heat pipe (5) all is provided with, what the outer fin (2) shown in the figure adopted is corrugated structure, Fig. 4 is the schematic diagram of the corrugated structure fin that amplifies, and its feature structure is: banded fin material (generally adopting aluminium strip and copper strips) is processed to continuous corrugated, adopts welding procedure (generally adopting soldering processes) again, be welded on the heat pipe (5), the corrugated two gear grinding formings that adopt shape simply the production efficiency height.Outer fin can adopt corrugated structure, and inner rib plate equally also can adopt corrugated structure.

Fig. 5 China and foreign countries' fins (2) are the nest plate type structures, Fig. 7 is the feature schematic diagram of its amplification, its feature structure is: the hole that the band flange is arranged on the fin, heat pipe inserts this hole, heat on the heat pipe (5) just imports on the outer fin (2) by the thermal contact conductance of flange and heat pipe (5), in order effectively to solve the contact heat resistance between flange and the heat pipe (5), should adopt welding procedure, generally adopt the tin soldering.Also has a difference between Fig. 5 and Fig. 3, adopting among Fig. 3 has two heat pipes, and has only a heat pipe among Fig. 5, and two ends are condensation segments, middle evaporation section is total for the two ends condensation segment, and air heat exchange unit section of being evaporated and the heat pipe stage casing be made up of condensation segment and outer fin (2) are separated into two sections.

In Fig. 6, adopting has four heat pipes, and by four sections air heat exchange units of being made up of heat pipe condenser section and outer fin, they are separate.Four sections air heat exchange units that separate are compared with two sections, the mobile average distance that liquid refrigerant is back to evaporation section from condensation segment in the heat pipe can reduce near half, when the radiating surface of components and parts is vertically placed, liquid refrigerant relies on siphon power backflow average height to reduce, this is very beneficial for the heat delivered in the heat pipe, thereby it is considered herein that, adopt as far as possible during design to be no less than four sections air heat exchange units of forming by heat pipe condenser section and outer fin that separate.

Outer fin (2) shown in Figure 6 is called as the laminated structure fin, Fig. 8 is the feature schematic diagram of its amplification, its feature structure is: outer fin (2) is by tired the gathering into folds of the independent diffusing sheet of slices, outer fin (2) root place flanging, this flanging is near heat pipe (5), heat on the heat pipe contacts with heat pipe (5) by this flanging exactly and passes on the outer fin (2), and outer fin (2) is welded on the heat pipe (5).Also having a flanging at fin root place shown in Fig. 6,8---location flanging (6), the pitch of fins between the fin are exactly to determine that by location flanging (6) also there is location flanging (6) at the point place of fin (2) outside.The location flanging (6) that fin root place and point place have been arranged just guarantees easily that the pitch of fins between the fin is even, is convenient to assembling, the production efficiency height.

Inner rib plate (3) can adopt laminated structure equally, as shown in figure 11.Aluminum extruded process technology limit the minimum thickness of fin, be generally 0.5mm, this is very thick, if inner rib plate adopts laminated structure or foregoing corrugated structure, because fin is to adopt strip (aluminium strip or copper strips) to be processed into, fin thickness is unrestricted, can be reduced to 0.1mm, can reduce the material usage and the weight of inner rib plate so widely, reduce the shared ventilation area of fin thickness, increase inner rib plate quantity.

In Fig. 9, fin (2) heat pipe (5) condensation segment inboard is provided with outside only, only the condensation segment outside at heat pipe (5) is provided with outer fin (2) in Figure 10, and these two kinds of structures have only just suitable employing when radiator overall dimension is restricted.

Identical feature also is shown in Fig. 3,5,6,9,10: one, inner rib plate (3) is along circumferentially towards a direction bending, crooked fin like this, advantage is: the difference of the pitch of fins at fin root place and point place reduces, can design and manufacture, pitch of fins unanimity from root to the point place, can guarantee that like this air fin of flowing through is even, help the integral heat sink face and be not fully exerted.If a root place pitch of fins is little, point place's pitch of fins is big, then flow through by the point place air capacity big, but because the thermal conduction resistance in the fin, the temperature at fin point place is lower than the temperature at root place, thereby heat radiation advantage in root place can not get effective utilization.A pitch of fins evenly also has an advantage to be: identical rib is long, identical fin number, and promptly total fin area is identical, and under the identical situation of heat-conducting block external diameter, the radiator external diameter is little, and is compacter.Thereby it is considered herein that the ratio of choosing a fin point place's pitch of fins and a root place pitch of fins must not be greater than 1.5.

Two, the evaporation section of heat pipe (5) and the heat pipe stage casing between the condensation segment, bending direction is consistent with the bending direction of inner rib plate (3), during design, as far as possible with the bending radius in heat pipe stage casing bending radius near inner rib plate (3), like this, can reduce the interference between heat pipe stage casing and the inner rib plate (3), reduce the space of the shared inner rib plate in heat pipe stage casing (3), guarantee quantity and its area of dissipation of inner rib plate (3), the installation of also being convenient to heat pipe cooperates.

According to thermal conduction study and aerodynamics, can learn: the cross-ventilation among the present invention in the fin conducts heat and belongs to convective heat transfer in the narrow slit, gap size between cross-ventilation heat exchange coefficient and the fin is inversely proportional to, that is to say that the gap is more little, be fin close more (radiator is compact more), the cross-ventilation heat exchange coefficient is high more.Thereby reduce a pitch of fins, not only increased area of dissipation, but also improve the cross-ventilation heat exchange coefficient, effect is to improve doublely, best clearance is below the 1mm, but considers the dust pollution problem in when operation, generally not gap design below 1mm, generally get the gap of 1.5mm, the gap between the fin in the air-conditioning in the heat exchanger is about 1.5mm.If the thick 0.4mm of fin, the gap between the fin is 1.5mm, and then a fin pitch of fins is that 1.9mm. it is considered herein that, it is reasonable value that a fin pitch of fins is chosen 2.0mm following, because a fin pitch of fins is not necessarily uniform, a pitch of fins described herein is an average pitch of fins.

In order further to improve the cross-ventilation heat of fin, reduce heat sink size, on fin, adopt and strengthen the convective heat transfer structure.Figure 12,13 shows short rib shape augmentation of heat transfer structure, Figure 12 is fork row formula short rib shape, Figure 10 is the venetian blind type short rib shape, their essential characteristic is: the surface that air is flowed through is die-cut into a section discontinuous surface, air whenever flow through one section (short rib), boundary layer on it all is in the The initial segment in boundary layer, makes whole heat convection surface make full use of the favourable characteristics that the boundary layer The initial segment is thin, thermal resistance is little, heat exchange coefficient is high.The width of short rib in 2.0 millimeter for well.

Fin is encrypted, and adopts enhanced heat exchange structure, will improve air flow resistance widely.Single-stage axial fan blast deficiency does not overcome the air flow resistance of fin, causes air quantity sharply to descend, and the air themperature in the fin of flowing through rises rapidly, and the heat transfer temperature difference of cross-ventilation heat exchange descends, and then heat dissipation capacity descends.The single-stage axial fan does not satisfy requirement, can adopt multistage axial flow formula fan and centrifugal fan, and the blast height can satisfy above requirement.

Claims

1, a kind of radiator that is used for cooling electronic device, include: heat-conducting block (4), inner rib plate (3), outer fin (2), heat pipe (5) and fan (1), one smooth heat-absorbent surface is arranged on the heat-conducting block (4), inner rib plate (3) is arranged on the side of heat-conducting block (4), outer fin (2) is on heat pipe (5), fan (1) be arranged on heat-absorbent surface back to a side, it is characterized in that: the evaporation section of heat pipe (5) is arranged on the heat-conducting block (4), the bending of heat pipe stage casing, the condensation segment of heat pipe (5) is provided with outer fin (2), be circular arc together, round inner rib plate (3); Round inner rib plate (3), the air heat exchange unit that has at least two sections condensation segment and outer fins (2) that separate to form by heat pipe (5).

2, radiator according to claim 1 is characterized in that: fan (1) is a centrifugal fan, or multistage axial flow formula fan.

3, radiator according to claim 1 is characterized in that: towards a direction bending, heat pipe stage casing bending direction is consistent with inner rib plate (3) bending direction along circumferentially for inner rib plate (3).

4, radiator according to claim 1 is characterized in that: flat tube is adopted in the condensation segment of heat pipe (5) and stage casing, or heat pipe (5) is side by side a heat pipe more than two or two.

5, radiator according to claim 1 is characterized in that: round inner rib plate (3), and the air heat exchange unit that has at least four sections condensation segment and outer fins (2) that separate to form by heat pipe (5).

6, radiator according to claim 1 is characterized in that: the evaporation section of heat pipe (5) is welding or is embedded on the heat-conducting block (4).

7, according to any one described radiator in the claim 1 to 6, it is characterized in that: inner rib plate (3) has adopted corrugated structure, or laminated structure, or the monolithic construction of aluminum extruded shaping.

8, according to any one described radiator in the claim 1 to 6, it is characterized in that: outer fin (2) has adopted laminated structure or corrugated structure or nest plate type structure; Outer fin (2) is welded on the heat pipe.

9, according to any one described radiator in the claim 1 to 6, it is characterized in that: outer fin (2) or inner rib plate (3) have adopted short rib shape augmentation of heat transfer structure.

10, according to any one described radiator in the claim 1 to 6, it is characterized in that: the average pitch of fins of inner rib plate (3) and outer fin (2) is not more than 2.0mm.