JP2020067269A - Heat pipe and method for manufacturing heat pipe - Google Patents
Heat pipe and method for manufacturing heat pipe Download PDFInfo
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title abstract description 5
- 239000002105 nanoparticle Substances 0.000 claims abstract description 69
- 239000012530 fluid Substances 0.000 claims abstract description 28
- 239000007788 liquid Substances 0.000 claims abstract description 15
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 29
- 239000010949 copper Substances 0.000 claims description 29
- 229910052802 copper Inorganic materials 0.000 claims description 29
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 239000000377 silicon dioxide Substances 0.000 claims description 12
- 238000009835 boiling Methods 0.000 claims description 7
- 238000002474 experimental method Methods 0.000 description 7
- 238000001704 evaporation Methods 0.000 description 6
- 230000008020 evaporation Effects 0.000 description 6
- 238000009833 condensation Methods 0.000 description 5
- 230000005494 condensation Effects 0.000 description 5
- 229910001120 nichrome Inorganic materials 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229910001369 Brass Inorganic materials 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 2
- 239000010951 brass Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
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- Cooling Or The Like Of Electrical Apparatus (AREA)
Abstract
Description
本発明は、作動流体が封入されたヒートパイプおよびヒートパイプ製造方法に関する。 The present invention relates to a heat pipe in which a working fluid is sealed and a heat pipe manufacturing method.
近年の電子機器や医療機器の小型化・高性能化に伴って、高発熱電子部品の冷却は、電子デバイス設計において重要な技術の一つとなっている(例えば特許文献1参照)。 With the recent miniaturization and higher performance of electronic devices and medical devices, cooling of high heat-generating electronic components has become one of the important techniques in electronic device design (see, for example, Patent Document 1).
特に、スマートフォンやタブレットPCでは、冷却デバイス用のスペースが限られているため、高発熱密度の電子素子の使用が難しく、高性能化の障害となっている。 In particular, in smartphones and tablet PCs, since the space for cooling devices is limited, it is difficult to use electronic elements with high heat generation density, which is an obstacle to higher performance.
本発明は上記課題に鑑みてなされたものであり、小型で熱輸送性能に優れたヒートパイプおよびヒートパイプ製造方法を提供することを課題とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat pipe and a heat pipe manufacturing method that are small in size and excellent in heat transport performance.
上記目的を達成するために、本発明に係るヒートパイプは、作動流体が封入されたコンテナと、前記コンテナの内壁面側に設けられ、前記作動流体の液体流路を形成するウィックとを備え、前記ウィックは、前記液体流路を形成するためのナノ粒子層で形成されていることを特徴とする。 In order to achieve the above object, the heat pipe according to the present invention includes a container in which a working fluid is enclosed, and a wick that is provided on the inner wall surface side of the container and forms a liquid flow path of the working fluid. The wick is formed of a nanoparticle layer for forming the liquid flow path.
また、本発明に係るヒートパイプ製造方法は、作動流体が封入されたコンテナと、前記コンテナの内壁面側に設けられ、前記作動流体の液体流路を形成するウィックとを備え、前記ウィックは、前記液体流路を形成するためのナノ粒子層で形成されていて、前記ナノ粒子層は、前記コンテナの内壁面に付着しているヒートパイプを製造する方法であって、前記コンテナを構成するパイプ部分の内側をシリカナノ流体に浸漬し、前記パイプ部分の内側で核沸騰させることで前記ナノ粒子層を形成することを特徴とする。 Further, the heat pipe manufacturing method according to the present invention comprises a container in which a working fluid is enclosed, and a wick provided on the inner wall surface side of the container and forming a liquid flow path of the working fluid, wherein the wick is A method for producing a heat pipe, comprising a nanoparticle layer for forming the liquid flow path, the nanoparticle layer being attached to an inner wall surface of the container, the pipe constituting the container. The inside of the portion is immersed in a silica nanofluid, and nucleate boiling is performed inside the pipe portion to form the nanoparticle layer.
また、本発明に係る別のヒートパイプ製造方法は、作動流体が封入されたコンテナと、前記コンテナの内壁面側に設けられ、前記作動流体の液体流路を形成するウィックとを備え、前記ウィックは、前記液体流路を形成するためのナノ粒子層で形成されていて、前記ナノ粒子層を表面に有するナノ粒子層付きメッシュを前記コンテナの内壁面側に備えるヒートパイプを製造する方法であって、メッシュを恒温槽に入れてシリカナノ流体に浸漬することで、前記ナノ粒子層付きメッシュを製造することを特徴とする。 Further, another heat pipe manufacturing method according to the present invention comprises a container in which a working fluid is enclosed, and a wick which is provided on the inner wall surface side of the container and forms a liquid flow path of the working fluid. Is a method of manufacturing a heat pipe, which is formed of a nanoparticle layer for forming the liquid flow path and has a mesh with a nanoparticle layer having the nanoparticle layer on the surface on the inner wall surface side of the container. Then, the mesh is placed in a constant temperature bath and immersed in a silica nanofluid to produce the mesh with the nanoparticle layer.
本発明によれば、小型で熱輸送性能に優れたヒートパイプおよびヒートパイプ製造方法を提供することができる。 According to the present invention, it is possible to provide a heat pipe and a heat pipe manufacturing method that are small in size and have excellent heat transport performance.
以下、添付図面を参照して、本発明の実施の形態について説明する。なお、以下に示す実施の形態は、この発明の技術的思想を具体化するための例示であって、構成部品の材質、形状、構造、配置等を下記のもののみに限定するものではない。この発明の実施の形態は、要旨を逸脱しない範囲内で種々変更して実施できる。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples for embodying the technical idea of the present invention, and the material, shape, structure, arrangement, etc. of the components are not limited to the following. The embodiments of the present invention can be variously modified and implemented without departing from the scope of the invention.
[第1実施形態]
図1で、(a)は、第1実施形態に係るヒートパイプの部分側面断面図、(b)は(a)の部分拡大図である。
[First Embodiment]
In FIG. 1, (a) is a partial side sectional view of the heat pipe according to the first embodiment, and (b) is a partially enlarged view of (a).
第1実施形態に係るヒートパイプHPは、作動流体(図示せず)が封入された銅製のコンテナCと、コンテナCの内壁面側に設けられ、作動流体の液体流路(図示せず)を形成するウィック(毛細管構造。図示せず)とを備える。ウィックは、液体流路を形成するためのナノ粒子層NLで形成されている。本実施形態では、ナノ粒子層NLは、コンテナCの内壁面に全面にわたって付着している。 The heat pipe HP according to the first embodiment is provided with a copper container C in which a working fluid (not shown) is enclosed, and a liquid flow path (not shown) for the working fluid, which is provided on the inner wall surface side of the container C. And a wick (capillary structure, not shown) to be formed. The wick is formed of a nanoparticle layer NL for forming a liquid flow path. In this embodiment, the nanoparticle layer NL is attached to the entire inner wall surface of the container C.
本実施形態では、ヒートパイプHPを製造する際、銅管Pの内側をシリカナノ流体(図示せず)に浸漬し、銅管Pの内側で核沸騰させることで、銅管Pの内壁面に付着したナノ粒子層NLを形成する。このように、高温に熱した固体をナノ流体に浸漬すると、固体の表面にナノ粒子層NLが形成される。なお、核沸騰させる際には銅管Pを上下方向に向けておくとナノ粒子層NLを効率良く形成することができる。また、シリカナノ流体以外のナノ流体を用いてシリカ以外のナノ粒子層(例えば、アルミナのナノ粒子層)を形成することも可能である。 In the present embodiment, when the heat pipe HP is manufactured, the inside of the copper pipe P is immersed in silica nanofluid (not shown), and nucleate boiling is performed inside the copper pipe P to adhere to the inner wall surface of the copper pipe P. The formed nanoparticle layer NL is formed. Thus, when the solid heated to a high temperature is immersed in the nanofluid, the nanoparticle layer NL is formed on the surface of the solid. It should be noted that the nanoparticle layer NL can be efficiently formed by orienting the copper tube P in the vertical direction during nucleate boiling. It is also possible to form a nanoparticle layer other than silica (for example, a nanoparticle layer of alumina) using a nanofluid other than the silica nanofluid.
そして、作動流体(例えば純水)を銅管Pに入れて銅管Pの両端を塞ぐことで第1実施形態に係るヒートパイプHPを製造する。 Then, a working fluid (for example, pure water) is put into the copper pipe P to close both ends of the copper pipe P, thereby manufacturing the heat pipe HP according to the first embodiment.
本実施形態では、コンテナCの内壁面側に、作動流体の液体流路を形成するウィックが設けられている。そしてこのウィックは、液体流路を形成するためのナノ粒子層NLで形成されている。すなわち、本実施形態に係るヒートパイプHPは、ナノ粒子層付ヒートパイプ(Nanoparticle-layer Pre-coated Heat Pipe)である。 In this embodiment, a wick that forms a liquid flow path for the working fluid is provided on the inner wall surface side of the container C. And this wick is formed by the nanoparticle layer NL for forming a liquid flow path. That is, the heat pipe HP according to the present embodiment is a nanoparticle-layer pre-coated heat pipe.
ナノ粒子層NLはきわめて薄く、強力な毛管力を有する。従って、ナノ粒子層NLのウィックによって、作動流体が液体のときには、作動流体がウィックで移動する速度(凝縮部から蒸発部へ移動する速度)は従来に比べて格段に速くなる。従って、小型で熱輸送性能に優れたヒートパイプHPが実現される。 The nanoparticle layer NL is extremely thin and has a strong capillary force. Therefore, due to the wick of the nanoparticle layer NL, when the working fluid is a liquid, the speed at which the working fluid moves by the wick (the speed at which the working fluid moves from the condensation section to the evaporation section) becomes significantly faster than in the conventional case. Therefore, a small-sized heat pipe HP having excellent heat transport performance is realized.
また、作動流体を純水にすることで、ナノ流体にする場合に比べ、安価で取扱いが極めて簡易なもの(純水)を作動流体とすることができる。 Further, by using pure water as the working fluid, it is possible to use a working fluid (pure water) that is cheap and extremely easy to handle as compared with the case of using nanofluid.
また、ナノ粒子層NLを安価に形成できるため、本実施形態のようにナノ粒子層NLをヒートパイプHPのウィックとして使用することで、冷却デバイスの小型化・高性能化・低価格化を通して、特に、スマートフォン等のモバイル機器の高性能化も達成可能である。 In addition, since the nanoparticle layer NL can be formed at low cost, by using the nanoparticle layer NL as the wick of the heat pipe HP as in the present embodiment, through downsizing, high performance, and low cost of the cooling device, In particular, high performance of mobile devices such as smartphones can be achieved.
[第2実施形態]
第2実施形態に係るヒートパイプは、ナノ粒子層NLを表面に有するナノ粒子層付きメッシュLM(図3参照)を備える。
[Second Embodiment]
The heat pipe according to the second embodiment includes the nanoparticle layer-equipped mesh LM (see FIG. 3) having the nanoparticle layer NL on the surface.
本実施形態では、メッシュ(例えば、真鍮製のメッシュBM(図2参照。裸のメッシュ)を恒温槽に入れてシリカナノ流体に浸漬することでナノ粒子層付きメッシュLMを製造する。 In this embodiment, a mesh (for example, a brass mesh BM (see FIG. 2; bare mesh) is placed in a thermostatic bath and immersed in a silica nanofluid to manufacture a mesh LM with a nanoparticle layer.
そして、このナノ粒子層付きメッシュLM(図3参照)および作動流体(例えば純水)を銅管P(図1参照)に入れて銅管Pの両端を塞ぐことで、第2実施形態に係るヒートパイプを製造する。 Then, the mesh LM with the nanoparticle layer (see FIG. 3) and the working fluid (for example, pure water) are put into the copper pipe P (see FIG. 1) to close both ends of the copper pipe P, thereby relating to the second embodiment. Manufacture heat pipes.
本実施形態では、第1実施形態に比べ、ナノ粒子層付きメッシュLMを予め製造しておき、これをコンテナ(銅管)の内壁面側に配置することができる。従って、第1実施形態のように銅管内側で核沸騰させる必要がない。よって、製造時の作業工程を単純化することができる。 In this embodiment, compared to the first embodiment, the nanoparticle layer-equipped mesh LM can be manufactured in advance and placed on the inner wall surface side of the container (copper tube). Therefore, it is not necessary to perform nucleate boiling inside the copper tube as in the first embodiment. Therefore, the work process at the time of manufacturing can be simplified.
また、メッシュにナノ粒子層NLを形成することで、毛管力が向上するので、熱輸送性能に優れたヒートパイプHPを実現できる。 Moreover, since the capillary force is improved by forming the nanoparticle layer NL on the mesh, it is possible to realize the heat pipe HP having excellent heat transport performance.
<実験例>
本発明者は、種々のヒートパイプの性能を調べる実験を行った。
<Experimental example>
The present inventor conducted experiments to investigate the performance of various heat pipes.
(実験例1)
(1)スクリーンメッシュへのナノ粒子層の形成
粗さ120目、長さ100mm、幅30mmの円筒状の真鍮製スクリーンメッシュを恒温槽に入れ、800℃雰囲気で5分間加熱した後、粒子濃度0.4kg/m3のシリカ(AEROXOIDE 90 G)ナノ流体に浸漬した。メッシュ全体にナノ粒子層を形成するために、この作業を3回にわたって繰り返した。
(Experimental example 1)
(1) Formation of a nanoparticle layer on a screen mesh A cylindrical brass screen mesh having a roughness of 120 meshes, a length of 100 mm and a width of 30 mm was placed in a constant temperature bath and heated at 800 ° C for 5 minutes, and then the particle concentration was 0.4. Immersed in kg / m 3 silica (AEROXOIDE 90 G) nanofluid. This operation was repeated 3 times to form a nanoparticle layer over the mesh.
そして、このようにしてナノ粒子層を形成したスクリーンメッシュ(ナノ粒子層付きメッシュLMの一例。図3参照)を、外径8mm、厚さ0.5mm、長さ100mmの銅管に挿入し、さらに作動流体(純水あるいはシリカナノ流体)を封入するとともに両端を塞ぐことで、ヒートパイプを製作した。ナノ粒子の付着量(酸化物の質量を含む)は12〜14 g/m2であった。ナノ粒子層形成前におけるスクリーンメッシュ(第2実施形態で説明したメッシュBMの一例)を図2に、ナノ粒子層形成後におけるスクリーンメッシュを図3に、それぞれ写真図で示す。 Then, the screen mesh (an example of the mesh LM with a nanoparticle layer, see FIG. 3) having the nanoparticle layer thus formed is inserted into a copper tube having an outer diameter of 8 mm, a thickness of 0.5 mm and a length of 100 mm, and further. A heat pipe was manufactured by enclosing a working fluid (pure water or silica nanofluid) and closing both ends. The amount of nanoparticles attached (including the mass of oxide) was 12-14 g / m 2 . A screen mesh before forming the nanoparticle layer (an example of the mesh BM described in the second embodiment) is shown in FIG. 2, and a screen mesh after forming the nanoparticle layer is shown in FIG.
(2)銅管内壁へのナノ粒子層の形成
図4は、実験例で、銅管内壁にナノ粒子層を形成することを説明する模式図である。
(2) Formation of Nanoparticle Layer on Inner Wall of Copper Tube FIG. 4 is a schematic diagram illustrating formation of a nanoparticle layer on the inner wall of the copper tube in an experimental example.
銅管Pの外部にニクロムワイヤヒーター30を巻き、耐熱ポリミドテープ32とフッ素テープ34とにより電気絶縁と断熱とを行う構造にした。 A nichrome wire heater 30 was wound on the outside of the copper pipe P, and a heat-resistant polyimide tape 32 and a fluorine tape 34 were used to provide electrical insulation and heat insulation.
そして、粒子濃度0.4 kg/m3のシリカナノ流体に浸漬した後、ボルトスライダー(図示せず)を用いて、ニクロムワイヤヒーター30に投入する交流電力を180 kW/m2に調節し、銅管Pの内面で核沸騰を生じさせ、ナノ粒子層NL(図5参照)をコンテナ内壁面に全面にわたって形成した。本手法で生成されるナノ粒子の付着量は1.5〜2.0 g/m2であった。 Then, after being immersed in a silica nanofluid having a particle concentration of 0.4 kg / m 3 , the AC power supplied to the nichrome wire heater 30 was adjusted to 180 kW / m 2 using a bolt slider (not shown), and the copper pipe P Nucleate boiling was caused on the inner surface of the container to form the nanoparticle layer NL (see FIG. 5) on the entire inner wall surface of the container. The amount of nanoparticles produced by this method was 1.5-2.0 g / m 2 .
図5に、ナノ粒子層NLを生成した銅管Pの内面を示す。なお、図5で部分的に白く見える部分は光の反射によるものである。 FIG. 5 shows the inner surface of the copper tube P on which the nanoparticle layer NL is generated. The part that appears white in FIG. 5 is due to the reflection of light.
(3)伝熱特性実験
ヒートパイプHPの伝熱特性実験を行う実験装置の概略を図6に示す。なお、ヒートパイプHPの製作は、外径8mm、厚さ0.5mm、長さ100mmの銅製円管を用いて製作した。
(3) Heat Transfer Characteristic Experiment FIG. 6 shows an outline of an experimental apparatus for conducting a heat transfer characteristic experiment of the heat pipe HP. The heat pipe HP was manufactured by using a copper circular tube having an outer diameter of 8 mm, a thickness of 0.5 mm and a length of 100 mm.
ヒートパイプHPの図6紙面左側の部分は蒸発部40であり、ニクロムワイヤヒーター42を用いて加熱する。ヒートパイプHPの図6紙面右側の部分は凝縮部44であり、銅製のフィン46を設置するとともに、ファン48を用いて冷却する。フィン46とヒートパイプHPとの間には、高熱伝導性のグリースを充填する。温度計測は、図6に示すヒートパイプHPの左端から5,15,25,40,50,60,75,85,95 mmの9ヶ所(図6で、T1〜T9で示す位置)にそれぞれスポット溶接したK型熱電対で行う。ヒートパイプHPへの投入電力Qは、ボルトスライダー50を用いて、3〜25Wの範囲で実験を行う。定常状態におけるヒートパイプHPの熱抵抗Rは、ヒートパイプHPの熱輸送量(すなわち投入電力)Qと蒸発部温度Te、凝縮部温度Tcを用いて、次式で定義した。 The portion of the heat pipe HP on the left side of the paper surface of FIG. 6 is the evaporation portion 40, which is heated by using the nichrome wire heater 42. A portion of the heat pipe HP on the right side of the paper surface of FIG. 6 is a condenser portion 44, which is provided with copper fins 46 and is cooled by using a fan 48. A high thermal conductive grease is filled between the fins 46 and the heat pipe HP. The temperature was measured at 9 points 5, 15, 25, 40, 50, 60, 75, 85, 95 mm from the left end of the heat pipe HP shown in FIG. 6 (positions indicated by T 1 to T 9 in FIG. 6). Each is spot-welded with a K-type thermocouple. For the input power Q to the heat pipe HP, an experiment is performed in the range of 3 to 25 W using the bolt slider 50. The thermal resistance R of the heat pipe HP in the steady state is defined by the following equation using the heat transport amount (that is, input power) Q of the heat pipe HP and the vaporizing portion temperature Te and the condensing portion temperature Tc.
R=(Te-Tc)/Q (式1)
(4)実験結果
(4−1)熱輸送量
(a)ナノ粒子層なしの銅管(Bare)、ナノ粒子層なしのメッシュ(Bare)、純水(Water)で製作したヒートパイプをBBW
(b)ナノ粒子層なしの銅管(Bare)、ナノ粒子層なしのメッシュ(Bare)、シリカナノ流体(粒子濃度0.2 kg/m3)(Nano)で製作したヒートパイプをBBN
(c)ナノ粒子層なしの銅管(Bare)、ナノ粒子層を形成したメッシュ(Nano)、純水(Water)で製作したヒートパイプをBNW
(d)ナノ粒子層を形成した銅管(Nano)、メッシュ無し(X)、純水(Water)で製作したヒートパイプをNXW
(e)ナノ粒子層を形成した銅管(Nano)、 ナノ粒子層なしのメッシュ(Bare)、純水(Water)で製作したヒートパイプをNBW
と呼称する。ここで,BBWは市販品であり、BBNは既存研究で以前に使用したものである。これ以外のBNW、 NXW、 NBWは、今までにないものであり、熱輸送性能を初めて検討するものである。
R = (Te-Tc) / Q (Formula 1)
(4) Experimental results (4-1) Heat transport amount (a) A copper pipe without a nanoparticle layer (Bare), a mesh without a nanoparticle layer (Bare), and a heat pipe made of pure water (BBW) is a BBW
(B) A copper pipe without a nanoparticle layer (Bare), a mesh without a nanoparticle layer (Bare), and a heat pipe made of silica nanofluid (particle concentration 0.2 kg / m 3 ) (Nano) are BBN
(C) BNW is a copper pipe without a nanoparticle layer (Bare), a mesh with a nanoparticle layer formed (Nano), and a heat pipe made with pure water (Water).
(D) Copper pipe with nanoparticle layer (Nano), no mesh (X), heat pipe made with pure water (Water) NXW
(E) NBW is a copper pipe (Nano) with a nanoparticle layer, a mesh without a nanoparticle layer (Bare), and a heat pipe made of pure water (Water).
I call it. Here, BBW is a commercial product and BBN is the one used previously in existing studies. Other BNWs, NXWs, and NBWs are unprecedented and are the first to be considered for heat transport performance.
上記5種類のヒートパイプを用いて、投入電力Qを徐々に変化させ、定常状態に至ったときの蒸発部−凝縮部間の温度差ΔTを実験的に調べた。得られたQとΔTとの関係を図7に示す。ここでΔTとは、(Te-Tc)の値である。 Using the above five types of heat pipes, the input power Q was gradually changed, and the temperature difference ΔT between the evaporation section and the condensation section when the steady state was reached was experimentally investigated. The relationship between the obtained Q and ΔT is shown in FIG. 7. Here, ΔT is a value of (Te-Tc).
まず、BBWとBBNを比較すると、全体的にBBNの方でΔTが小さくなっており、ヒートパイプの作動流体としてナノ流体を使用することの有効性が確認できる。次に、スクリーンメッシュにナノ粒子層を形成したBNWでは,入力熱量が3〜9Wでは温度差ΔTはBBNとほぼ同じだが、入力熱量9〜25WではΔTがむしろ大きい値となっている。これは、メッシュの目詰まりにより、作動流体の搬送性能が劣化したことが主な原因として考えられる。 First, comparing BBW and BBN, ΔT is smaller in BBN as a whole, and the effectiveness of using nanofluid as the working fluid of the heat pipe can be confirmed. Next, in the BNW with a nanoparticle layer formed on the screen mesh, the temperature difference ΔT is almost the same as BBN when the input heat amount is 3 to 9 W, but ΔT is rather large when the input heat amount is 9 to 25 W. It is considered that this is mainly because the performance of the working fluid is deteriorated due to the clogging of the mesh.
次に、NXWとNBWでは、BBWやBBNと比較して、ΔTが15〜40%程度低下しており、熱輸送性能の向上が認められる。すなわち、コンテナCの内壁面に全面にわたって、つまりヒートパイプ内面の全面にわたってナノ粒子層NLを形成しておくことで、単に作動流体としてナノ流体を用いる場合と比較しても、数十%程度、伝熱性能が向上することが認められる。したがって、管内壁にナノ粒子層を形成することで、熱輸送性能の向上が期待できるといえる。特に、メッシュを設置していないNXWでも、BBWやBBNを凌ぐ性能を呈していることは興味深い。 Next, in NXW and NBW, ΔT is reduced by about 15 to 40% compared to BBW and BBN, and improvement in heat transport performance is recognized. That is, by forming the nanoparticle layer NL over the entire inner wall surface of the container C, that is, over the entire inner surface of the heat pipe, even when compared with the case where the nanofluid is simply used as the working fluid, about several tens%, It is recognized that the heat transfer performance is improved. Therefore, it can be said that the heat transport performance can be expected to be improved by forming the nanoparticle layer on the inner wall of the tube. In particular, it is interesting that the NXW, which does not have a mesh installed, also outperforms the BBW and BBN.
(4−2)熱抵抗
(式1)より、各ヒートパイプについて入力熱量(すなわち投入電力)Qと熱抵抗Rの関係に換算した結果を図8に示す。NXWとNBWに着目すると、Q = 3〜9Wの低熱輸送量条件では、BBWやBBN等の既存仕様と比較してRが高い値を示しているが、Q = 9〜25 Wの高熱輸送量条件では13〜32%程度の熱抵抗の低減効果が得られている。
(4-2) Thermal resistance FIG. 8 shows a result obtained by converting the relationship between the input heat quantity (that is, input power) Q and the thermal resistance R for each heat pipe from (Equation 1). Focusing on NXW and NBW, under low heat transport conditions of Q = 3 to 9 W, R shows a higher value than existing specifications such as BBW and BBN, but high heat transport amount of Q = 9 to 25 W. Under the conditions, the effect of reducing the thermal resistance by 13 to 32% is obtained.
(5)まとめ
入力熱量3〜25Wの条件において、ナノ粒子層を形成したスクリーンメッシュ及び内壁にナノ粒子層を形成した銅管を用いて製作したヒートパイプの熱輸送性能を調べ、既存仕様のヒートパイプと比較した。得られた主な結論を以下に要約する。
(5) Summary Under the condition of the input heat quantity of 3 to 25 W, the heat transport performance of the heat pipe manufactured by using the screen mesh with the nanoparticle layer and the copper tube with the nanoparticle layer formed on the inner wall was investigated, and the heat of the existing specifications was examined. Compared to the pipe. The main conclusions obtained are summarized below.
(5−1)スクリーンメッシュにナノ粒子層を形成したヒートパイプでは、入力熱量3〜9Wで2〜8%程度の熱抵抗の低下が生じた。 (5-1) In the heat pipe in which the nanoparticle layer is formed on the screen mesh, the thermal resistance is reduced by about 2 to 8% when the input heat amount is 3 to 9W.
なお、9〜25Wの条件では、熱抵抗がむしろ増大した。ナノ粒子層あるいは高温に熱した際に形成される酸化層により、作動流体の輸送が阻害されたことが、熱抵抗増大の一因と考えられる。 The thermal resistance was rather increased under the condition of 9 to 25W. The transport of the working fluid is hindered by the nanoparticle layer or the oxide layer formed when heated to a high temperature, which is considered to be one of the causes of the increase in thermal resistance.
(5−2)銅管内壁にナノ粒子層を形成したヒートパイプでは、入力熱量3〜9Wでは熱抵抗が増大するものの、9〜25Wでは13〜32%程度の熱抵抗の低減が認められた。特に、メッシュを設置しない場合でも、既存仕様より良好な伝熱性能を得られたことは、小型の熱輸送デバイスを開発する上で有用と考えられる。 (5-2) In the heat pipe in which the nanoparticle layer was formed on the inner wall of the copper tube, the thermal resistance increased at an input heat amount of 3 to 9 W, but a reduction of 13 to 32% was observed at 9 to 25 W. . In particular, even if the mesh is not installed, the fact that the heat transfer performance is better than the existing specifications is considered to be useful in developing a small heat transport device.
(実験例2)
実験例2では、作動流体(純水)の充填率をいずれも約15%(15±1%)としたBBW、BNW、およびNBWに対し、図6の実験装置を用いた実験例1と同様の伝熱特性実験を行った。ここで、BNWおよびNBWは、実験例1と同様の製造方法により製造したものである。
(Experimental example 2)
In Experimental Example 2, for the BBW, BNW, and NBW in which the filling rate of the working fluid (pure water) was approximately 15% (15 ± 1%), the same as in Experimental Example 1 using the experimental apparatus of FIG. The heat transfer characteristic experiment was conducted. Here, BNW and NBW are manufactured by the manufacturing method similar to Experimental example 1.
実験例2で得られたQとΔTとの関係を図9に示す。また、QとΔTとの関係をQとRとの関係に換算した結果を図10に示す。 FIG. 9 shows the relationship between Q and ΔT obtained in Experimental Example 2. FIG. 10 shows the result of converting the relationship between Q and ΔT into the relationship between Q and R.
図10に示すように、BNWではBBWに対し、Rの値が大幅に小さくなっている(平均的に約50%)。すなわち、メッシュにナノ粒子層を形成することで、毛管力が向上し、熱輸送性能が向上することが認められる。 As shown in FIG. 10, the value of R is significantly smaller than that of BBW in BNW (about 50% on average). That is, it is recognized that the capillary force is improved and the heat transport performance is improved by forming the nanoparticle layer on the mesh.
なお、NBWではBBWに対して、Rの値は大きくは変わらないが、Q が大きい条件ではRの値の低下が認められる。 Note that the value of R in NBW does not change much from that of BBW, but a decrease in R is observed under the condition of large Q.
BM メッシュ
C コンテナ
HP ヒートパイプ
LM ナノ粒子層付きメッシュ
NL ナノ粒子層
P 銅管
30 ニクロムワイヤヒーター
32 耐熱ポリミドテープ
34 フッ素テープ
40 蒸発部
42 ニクロムワイヤヒーター
44 凝縮部
46 フィン
48 ファン
50 ボルトスライダー
BM mesh C container HP heat pipe LM nano particle layer mesh NL nano particle layer P copper tube 30 nichrome wire heater 32 heat resistant polyimide tape 34 fluorine tape 40 evaporation part 42 nichrome wire heater 44 condensation part 46 fins 48 fan 50 bolt slider
Claims (8)
前記コンテナの内壁面側に設けられ、前記作動流体の液体流路を形成するウィックと
を備え、
前記ウィックは、前記液体流路を形成するためのナノ粒子層で形成されていることを特徴とするヒートパイプ。 A container containing a working fluid,
A wick provided on the inner wall surface side of the container and forming a liquid flow path of the working fluid,
The heat pipe according to claim 1, wherein the wick is formed of a nanoparticle layer for forming the liquid flow path.
前記コンテナを構成するパイプ部分の内側をシリカナノ流体に浸漬し、前記パイプ部分の内側で核沸騰させることで前記ナノ粒子層を形成することを特徴とするヒートパイプ製造方法。 A heat pipe manufacturing method for manufacturing the heat pipe according to claim 2,
A method for producing a heat pipe, characterized in that the inside of a pipe portion constituting the container is immersed in a silica nanofluid, and the nanoparticle layer is formed by nucleate boiling inside the pipe portion.
メッシュを恒温槽に入れてシリカナノ流体に浸漬することで、前記ナノ粒子層付きメッシュを製造することを特徴とするヒートパイプ製造方法。 A heat pipe manufacturing method for manufacturing the heat pipe according to claim 3,
A method for producing a heat pipe, characterized in that the mesh with a nanoparticle layer is produced by placing the mesh in a constant temperature bath and immersing it in a silica nanofluid.
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