201226823 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種散熱裝置，尤指一種適用於有效排 逸廢熱之散熱裝置》 【先前技術】 目前散熱市場中，熱管因具有優異的熱傳性能，故成 為使用最為廣泛之技術，並普遍應用於各種散熱系統中。 增加熱管之熱傳導特性係現今熱管發展之重點，而主要研 究方向有：改變熱管結構及改變工作流體。 就工作流體而言，奈米流趙係最近的研究潮流，其將 奈米尺寸的金屬或非金屬奈米粒子懸浮於流體中，以改變 流體的基本流動及熱傳特性，且無以往添加大顆粒於流體 後所造成之流道阻塞及壓降問題。習知使用之奈米流體顆 粒主要包括：如金、銀、銅等金屬奈米粒子：如氧化鋁、 氧化銅、一氧化石夕等氧化物奈米粒子；及奈米碳管等。另 外’亦有人提出可使用磁性奈米流體作為工作流體其中 已提出有各種磁性奈米粒子之製備方法，如台灣專利 TW096116233號所揭露之超順磁性粒子，然而，將磁性奈 米粒子應用於散熱系統中仍有發展改善之空間。另一方 面，就熱管結構而言，目前使用之熱管主要有：單管式熱 管、迴路式熱管及迴路脈衝式熱管。 如圖1Α所示，習知單管式熱管係由封閉管體U所構 成，其内壁上披覆有毛細結構13 ,且内部設有工作流體Μ。 201226823 據此，如圖1A所示，當單管式熱管之蒸發部B1之工作流體 14受熱汽化時，汽化而成之氣相會往冷凝部B2移動（如箭頭 所示），並於冷凝部B2將氣相冷凝成液相，而冷凝後之液相 將藉由毛細結構13之毛细力流回蒸發部B1 (如箭頭所示）。 於單管式熱管中，由於蒸發氣相與冷凝液係於同一流道流 動’故流速大之蒸氣容易對冷凝液產生剪力，遂使冷凝液 無法流回蒸氣部，進而導致蒸發部發生乾燒的現象。此外， 若單管式熱管所使用之工作流體為奈米流體時，蒸發時所 發生之固氣相分離現象會使奈米粒子仍留置於蒸發部，反 而導致熱阻增加。 曰本專利JP5 71085 93號即揭露一種單管式熱管充填磁 性流體之散熱裝置’其雖利用總繞於熱管外部之電磁線圈 來加速磁性流體之速度’但由於蒸發氣相與冷凝液仍於同 一流道流動，故蒸氣仍易阻礙冷凝液流回蒸發部，且蒸發 時所發生之固氣相分離現象容易使磁性粒子仍留置於蒸發 部，導致熱阻增加。 為解決上述蒸發部易乾燒之問題，另提出有迴路式熱 管之技術。如圖1B所示，習知迴路式熱管係藉由封閉式迴 路官21内的工作流體24於蒸發部B1與冷凝部B2進行熱交 換’其中蒸發氣相與冷凝液係於不同流道流動，故可避免 蒸氣對冷凝液產生剪力而造成冷凝液無法流回蒸氣部之問 題。 另一方面’為解決上述奈米粒子與氣相分離之問題， 另提出有迴路脈衝式熱管之技術。如圖1C所示，習知迴路 201226823 脈衝式熱管主要係由多支熱管串聯構成之多迴路式管體 31 ’其中工作流體34於該多迴路式管體31中可形成氣相與 奈米流體之傳輸單元，以避免奈米粒子留置於蒸發部B i。 然而，該習知迴路脈衝式熱管卻有構造複雜且所佔空間極 大之缺點。 此外，日本專利jP57〇96557號、日本專利JP8〇14779號 及。灣專利TW097145 608號另揭露一種藉由工作流體於雙 管分流之結構中流動而帶走熱之技術，其中，為增加熱導 效果，其增加接觸面積並設有多數檔板或散熱鰭片，使工 作流體能充分進行熱交換。然而，此結構卻可能導致工作 流體流速減緩，反而無法達到快速散熱之目的。尤其，若 此結構使用奈米流體作為工作流體，亦可能因氣固分離而 導致熱阻上升。 【發明内容】 本發明之目的係在提供一種散熱裝置，俾能提高散熱 效率，且具有結構簡單及不佔空間等優點。 為達成上述目的，本發明提供一種散熱裝置，包括： 外管，一内管，係設置於該外管内，其中該内管之内部 空間構成-第-腔體，而該内管與該外管間之空間則構成 一第二腔鱧，且該内管之兩端壁上具有複數個開孔，以使 。亥第腔體與該第二腔體互相連通；以及一磁性奈米流 體，係填充於該第-腔體及該第二腔體中，其中該磁性奈 米流體包括一液態流體及複數個磁性奈米粒子。 201226823 據此’本發明係藉由雙套管之熱管結構，使工作流體 (即磁性奈米流體）之蒸發氣相及高溫液相與冷凝液於不同 流道流動’以避免習知單管式熱管易發生之蒸發部乾燒問 題。在此，本發明散熱裝置中所填充的磁性奈米流體受熱 時’液態流體可藉由蒸發與冷凝之熱傳方式，以達到快速 傳遞熱量之效果；除此之外，更可藉由磁性奈米流體中粒 子與粒子間的碰撞及粒子與管壁的碰撞，以有效提升熱傳 效果。尤其，本發明散熱裝置中之内管兩端壁上因形成具 有類似喷嘴作用之開孔，故可使磁性奈米流體受熱時形成 氣液相共存之傳輸單元’以避免習知單管式熱管易發生粒 子留置蒸發部導致熱阻上升之問題，且無須再增加接觸面 積或增設檔板或散熱鰭片即可展現優異之熱導效果，俾可 避免接觸面積增加或增設檔板或散熱鰭片導致工作流體流 速減緩之問題，以達到快速散熱之目的。相較於習知迴路 脈衝式熱管，本發明之散熱裝置可展現優異之熱傳特性， 且具有結構較為簡單、製作成本較低及體積較小之優點。 本發明之散熱裝置更可包括：一毛細結構，係披覆於 該第一腔體或該第二腔體之内壁上。據此，冷凝後之液態 机體除了重力作用外’其更可藉由毛細作用，快速回流至 蒸發部，以提高熱傳效率。 本發明之散熱裝置更可包括：一磁場產生單元，係設 置於該内管之外圍或該内管中。據此，該磁場產生單元可 增加局部磁場’進一步提高磁性奈米流體之熱導係數。 201226823 於本發明中’磁性奈米流體十之磁性奈米粒子並無特 =限制’其可為任何具有磁性之奈米粒子如三氧化二鐵 奈，子、四氧化三鐵奈米粒子或其混合物等，且粒徑較 佳疋小於10 run;此外，磁性奈|流體中之液態流體亦無特 殊限制’其可為任何習知適用於熱管中之液態流體，舉例 如水、油、丙酮、癸烯、乙二醇、氟化液或其混合；再者， 磁性奈米粒子於液態流體中之濃度較佳為 1 ·6χ 10-2 emu/g至 8 emu/g。 於本發明中，以散熱裝置總體積為基準’該磁性奈米 流體之充填量較佳為裝置總體積之3〇至5〇體積百分比。 於本發明中，該毛細結構並無特殊限制，其可為任何 駕知之毛細結構，舉例包括絲網結構（如銅網）、溝槽結構、 燒結結構、纖維結構或蝕刻結構等。 於本發明中，散熱裝置之兩端可分別為一蒸發部及一 冷凝部。在此’蒸發部與冷凝部可使用疏密程度不同之毛 細結構’較佳為，蒸發部使用密度較密之毛細結構（即，蒸 發部處之毛細結構密度高於冷凝部處之毛細結構密度），以 提昇工作流韹蒸發量。 於本發明中，該磁性奈米流趙可於一傳輸流道中產生 氣液相共存之傳輸單元，俾能有效地將廢熱由蒸發部傳 導至冷凝部排逸。於此，而該傳輸流道可位於該第一腔體 或該第二腔體中。詳細地說，傳輸流道可位於第一腔體中， 而毛細結構則可披覆於第二腔體之内壁上；或者，傳輸流 201226823 道係於第二腔體中，而毛細結構則係披覆於第一腔體之内 壁上。 於本發明中，當傳輸流道係位於第一腔體中時，第一 腔體或第二腔體可包括一容置部，其係位於該傳輸流道之 外側，俾使磁場產生單元可設置於該容置部中。另一方面， 當傳輸流道係位於第二腔體中時，第二腔體則可包括一容 置部’其係位於該傳輸流道之外側’俾使磁場產生單元可 Φ 6又置於該谷置部中。又，該磁場產生單元亦可設置於該外 管之外側。據此，該磁場產生單元所產生之磁場可橫向穿 過該傳輸流道。此外，該磁場產生單元較佳係產生適當強 度之磁場，俾可於不影響磁性奈米流體流動下增加局部磁 場，避免磁性奈米粒子吸附於管中，造成散熱裝置之熱傳 性能下降。較佳為，磁場產生單元於傳輸流道之磁場強度 為1000 Oe至4000 Oe，更佳為1000 〇e至3000 〇e，最佳為 2000 Oe «> 於本發明中，該磁場產生單元並無特殊限制，其可為 • 任何可產生磁場之元件，如環狀靜磁鐵、四極式靜磁鐵、 電磁鐵等》 本發明之散熱裝置更可包括：一感應線圈，係設置於 該外管之外圍’俾使該感應線圈可因磁性流體流動所造成 之磁場變化而產生感應電流》據此，該散熱裝置亦可與— 電力裝置（如風扇、USB、電池等）電性連接，以提供電力予 該電力裝置。 201226823 承上所述’本發明係藉由雙套管之熱管結構，使工作 流體（即磁性奈来流體）之蒸發氣相及高溫液相與冷凝液於 不同流道流動’以避免習知單管式熱管易發生之蒸發部乾 燒問題。在此’本發明散熱裝置中所填充的磁性奈米流體 受熱時’液態流體可藉由蒸發與冷凝之熱傳方式，以達到 快速傳遞熱量之效果；除此之外，更可藉由磁性奈求流體 中粒子與粒子間的碰撞及粒子與管壁的碰揸，以有效提升 熱傳效果。尤其，本發明散熱裝置中之内管兩端壁上因形 成具有類似喷嘴作用之開孔，故可使磁性奈米流體受熱時 形成氣液相共存之傳輸單元’以避免習知單管式熱管易發 生粒子留置蒸發部導致熱阻上升之問題，且無須再增加接 觸面積或增設檔板或散熱鰭片即可展現優異之熱導效果， 俾可避免接觸面積增加或增設檔板或散熱鰭片導致工作流 體流速減緩之問題，以達到快速散熱之目的：再者，本發 明散熱裝置更可設置有磁場產生單元，以增加局部磁場， 提高磁性奈米流體之熱導係數。相較於習知迴路脈衝式熱 官’本發明之散熱裝置可展現優異之熱傳特性，且具有結 構較為簡單、製作成本較低及體積較小之優點。 【實施方式】 以下係藉由特定的具體實施例說明本發明之實施方 式’熟習此技藝之人士可由本說明書所揭示之内容輕易地 了解本發明之其他優點與功效。本發明亦可藉由其他不同 的具體實施例加以施行或應用，本說明書中的各項細節亦 201226823 ’在不悖離本發明之精神下進行各 可基於不同觀點與應用 種修飾與變更。 實施例1 月參見圖2其係為本發明一較佳實施例之散熱裝置示 意圖。201226823 VI. Description of the Invention: [Technical Field] The present invention relates to a heat dissipating device, and more particularly to a heat dissipating device suitable for effectively exhausting waste heat. [Prior Art] In the current heat dissipating market, the heat pipe has excellent heat transfer. Performance is the most widely used technology and is widely used in various cooling systems. Increasing the heat transfer characteristics of heat pipes is the focus of today's heat pipe development, and the main research directions are: changing the heat pipe structure and changing the working fluid. In terms of working fluids, the recent research trend of Nanoflow Zhao is to suspend nanometer-sized metal or non-metallic nanoparticles in a fluid to change the basic flow and heat transfer characteristics of the fluid, without adding large The problem of channel blockage and pressure drop caused by the particles after the fluid. The nanometer fluid particles used in the prior art mainly include: metal nanoparticles such as gold, silver, copper, etc.: oxide nanoparticles such as alumina, copper oxide, and nitric oxide; and carbon nanotubes. In addition, it has also been proposed to use a magnetic nanofluid as a working fluid. Among them, various magnetic nanoparticle particles have been proposed, such as the superparamagnetic particles disclosed in Taiwan Patent No. TW096116233. However, magnetic nanoparticles are used for heat dissipation. There is still room for improvement in the system. On the other hand, in terms of heat pipe structure, the heat pipes currently used mainly include: single-tube heat pipes, loop-type heat pipes, and circuit-pulse heat pipes. As shown in Fig. 1A, the conventional single-tube heat pipe is composed of a closed pipe body U, the inner wall of which is covered with a capillary structure 13 and internally provided with a working fluid. According to this, as shown in FIG. 1A, when the working fluid 14 of the evaporation portion B1 of the single-tube heat pipe is heated and vaporized, the vaporized vapor phase moves to the condensation portion B2 (as indicated by the arrow), and is in the condensation portion. B2 condenses the gas phase into a liquid phase, and the condensed liquid phase will flow back to the evaporation portion B1 by the capillary force of the capillary structure 13 (as indicated by the arrow). In the single-tube heat pipe, since the vaporized gas phase and the condensate flow in the same flow channel, the vapor having a large flow velocity easily shears the condensate, so that the condensate cannot flow back to the vapor portion, thereby causing the evaporation portion to dry. The phenomenon of burning. In addition, if the working fluid used in the single-tube heat pipe is a nanofluid, the solid-gas phase separation occurring during evaporation causes the nanoparticles to remain in the evaporation portion, which in turn causes an increase in thermal resistance. JP 5 71085 93 discloses a heat dissipation device for a single-tube heat pipe filled with a magnetic fluid, which utilizes an electromagnetic coil that is always wound around the outside of the heat pipe to accelerate the velocity of the magnetic fluid, but is still the same as the condensate due to evaporation of the gas phase. The first-class flow, so the vapor still easily hinders the flow of the condensate back to the evaporation portion, and the solid-gas separation phenomenon occurring during evaporation tends to leave the magnetic particles still in the evaporation portion, resulting in an increase in thermal resistance. In order to solve the problem of easy drying of the above-mentioned evaporation section, a technique of a loop type heat pipe has been proposed. As shown in FIG. 1B, the conventional loop heat pipe performs heat exchange between the evaporation portion B1 and the condensation portion B2 by the working fluid 24 in the closed circuit breaker 21, wherein the vaporization gas phase and the condensate flow in different flow paths. Therefore, the problem that the vapor can cause shearing force to the condensate and the condensate cannot flow back to the vapor portion can be avoided. On the other hand, in order to solve the problem of separating the above-mentioned nanoparticle from the gas phase, a technique of a loop pulse type heat pipe has been proposed. As shown in FIG. 1C, the conventional circuit 201226823 pulse heat pipe is mainly a multi-circuit pipe body 31 composed of a plurality of heat pipes connected in series. The working fluid 34 can form a gas phase and a nano fluid in the multi-circuit pipe body 31. The transfer unit prevents the nanoparticles from remaining in the evaporation portion B i . However, the conventional loop pulse type heat pipe has the disadvantages of complicated structure and large space occupation. In addition, Japanese Patent No. jP57〇96557, Japanese Patent No. JP8〇14779 and. Bay Patent No. TW097145 No. 608 discloses a technique for removing heat by flowing a working fluid in a double-tube split structure, wherein in order to increase the thermal conductivity effect, it increases the contact area and is provided with a plurality of baffles or fins. The working fluid can be fully exchanged for heat. However, this structure may cause the working fluid flow rate to slow down, but it may not achieve the purpose of rapid heat dissipation. In particular, if the structure uses a nanofluid as a working fluid, it may also cause an increase in thermal resistance due to gas-solid separation. SUMMARY OF THE INVENTION The object of the present invention is to provide a heat dissipating device which can improve heat dissipation efficiency and has the advantages of simple structure and no space occupation. In order to achieve the above object, the present invention provides a heat dissipating device, comprising: an outer tube, an inner tube disposed in the outer tube, wherein an inner space of the inner tube constitutes a first cavity, and the inner tube and the outer tube The space between the two forms a second cavity, and the inner tube has a plurality of openings on both end walls thereof. The first cavity and the second cavity are in communication with each other; and a magnetic nanofluid is filled in the first cavity and the second cavity, wherein the magnetic nanofluid comprises a liquid fluid and a plurality of magnetic Nano particles. 201226823 According to the present invention, the double-casing heat pipe structure allows the vaporization of the working fluid (ie, magnetic nanofluid) and the high-temperature liquid phase and the condensate to flow in different flow paths to avoid the conventional single tube type. The heat pipe is prone to dry burning in the evaporation department. Here, when the magnetic nano-filled fluid filled in the heat-dissipating device of the present invention is heated, the liquid fluid can be heat-transferred by evaporation and condensation to achieve the effect of rapidly transferring heat; in addition, The collision between particles and particles in the rice fluid and the collision of the particles with the tube wall to effectively improve the heat transfer effect. In particular, in the heat dissipating device of the present invention, the end wall of the inner tube is formed with an opening having a nozzle-like function, so that the magnetic nano-fluid can form a gas-liquid phase coexisting transmission unit when heated, so as to avoid the conventional single-tube heat pipe. It is prone to the problem that the thermal retention of the particles is caused by the indwelling of the particles, and the thermal contact effect can be exhibited without increasing the contact area or adding baffles or fins. The contact area can be increased or the baffles or fins can be added. The problem of slowing the flow rate of the working fluid is to achieve rapid heat dissipation. Compared with the conventional loop pulse heat pipe, the heat dissipating device of the invention can exhibit excellent heat transfer characteristics, and has the advantages of simple structure, low manufacturing cost and small volume. The heat sink of the present invention may further comprise: a capillary structure covering the inner wall of the first cavity or the second cavity. According to this, the condensed liquid body can be quickly returned to the evaporation portion by capillary action in addition to the action of gravity to improve the heat transfer efficiency. The heat sink of the present invention may further comprise: a magnetic field generating unit disposed in the periphery of the inner tube or in the inner tube. Accordingly, the magnetic field generating unit can increase the local magnetic field' to further increase the thermal conductivity of the magnetic nanofluid. 201226823 In the present invention, the magnetic nanoparticle of the magnetic nanofluid has no special limitation. It can be any magnetic nanoparticle such as ferritic trioxide, ferrite, or ferroferric oxide particles. Mixture, etc., and preferably having a particle size of less than 10 run; in addition, the liquid fluid in the fluid is not particularly limited. It can be any liquid fluid suitable for use in heat pipes, such as water, oil, acetone, hydrazine. Further, the concentration of the magnetic nanoparticles in the liquid fluid is preferably from 1. 6 χ 10-2 emu/g to 8 emu/g. In the present invention, the filling amount of the magnetic nanofluid is preferably from 3 Torr to 5 Torr based on the total volume of the heat sink. In the present invention, the capillary structure is not particularly limited, and may be any capillary structure that is known, and includes, for example, a wire mesh structure (e.g., a copper mesh), a groove structure, a sintered structure, a fiber structure, or an etched structure. In the present invention, both ends of the heat dissipating device may be an evaporation portion and a condensation portion, respectively. Here, the 'evaporation portion and the condensation portion may use a capillary structure having a different degree of density". Preferably, the evaporation portion uses a denser capillary structure (that is, the capillary structure density at the evaporation portion is higher than the capillary structure density at the condensation portion). ) to increase the amount of workflow evaporation. In the present invention, the magnetic nanoflow can generate a gas-liquid phase coexisting transport unit in a transport flow path, and the waste heat can be efficiently conducted from the evaporation portion to the condensation portion. Here, the transport flow path can be located in the first cavity or the second cavity. In detail, the transport flow path may be located in the first cavity, and the capillary structure may be coated on the inner wall of the second cavity; or, the transport stream 201226823 is in the second cavity, and the capillary structure is Covered on the inner wall of the first cavity. In the present invention, when the transport flow channel is located in the first cavity, the first cavity or the second cavity may include a receiving portion located on the outer side of the transport flow path, so that the magnetic field generating unit can It is disposed in the accommodating portion. On the other hand, when the transport channel is located in the second cavity, the second cavity may include a receiving portion 'which is located outside the transport channel', so that the magnetic field generating unit can be placed in the Φ 6 The valley is in the middle. Further, the magnetic field generating unit may be disposed outside the outer tube. Accordingly, the magnetic field generated by the magnetic field generating unit can transversely pass through the transport flow path. In addition, the magnetic field generating unit preferably generates a magnetic field of a suitable intensity, and the local magnetic field can be increased without affecting the flow of the magnetic nano-fluid, and the magnetic nano-particles are prevented from being adsorbed into the tube, thereby causing a decrease in heat transfer performance of the heat dissipating device. Preferably, the magnetic field generating unit has a magnetic field intensity in the transport channel of 1000 Oe to 4000 Oe, more preferably 1000 〇e to 3000 〇e, and most preferably 2000 Oe «> in the present invention, the magnetic field generating unit The heat dissipating device of the present invention may further include: an induction coil disposed on the outer tube, wherein the heat dissipating device of the present invention may further include: an element capable of generating a magnetic field, such as a ring magnet, a quadrupole magnet, an electromagnet, or the like. The peripheral '俾 causes the induction coil to generate an induced current due to a change in the magnetic field caused by the flow of the magnetic fluid. Accordingly, the heat sink can also be electrically connected to the power device (such as a fan, USB, battery, etc.) to provide power. The electric device is given. 201226823 According to the above description, the present invention uses a double-tube heat pipe structure to cause an evaporating gas phase and a high-temperature liquid phase of a working fluid (ie, a magnetic nanofluid) to flow in a different flow path with a condensate to avoid a conventional single. The tubular heat pipe is prone to dry burning problems in the evaporation section. Here, when the magnetic nano-filled fluid filled in the heat-dissipating device of the present invention is heated, the liquid fluid can be heat-transferred by evaporation and condensation to achieve the effect of rapidly transferring heat; in addition, it can be magnetically The collision between the particles and the particles in the fluid and the collision of the particles with the tube wall are sought to effectively improve the heat transfer effect. In particular, in the heat dissipating device of the present invention, the end wall of the inner tube is formed with an opening having a nozzle-like function, so that the magnetic nano-fluid can form a gas-liquid phase coexisting transmission unit when heated, so as to avoid the conventional single-tube heat pipe. It is prone to the problem that the thermal retention of the particles is caused by the indwelling of the particles, and the thermal contact effect can be exhibited without increasing the contact area or adding baffles or fins. The contact area can be increased or the baffles or fins can be added. The problem that the working fluid flow rate is slowed down is to achieve the purpose of rapid heat dissipation. Furthermore, the heat dissipating device of the present invention can be further provided with a magnetic field generating unit to increase the local magnetic field and improve the thermal conductivity of the magnetic nanofluid. Compared with the conventional circuit pulse type heat-receiving device, the heat dissipating device of the present invention can exhibit excellent heat transfer characteristics, and has the advantages of simple structure, low manufacturing cost and small volume. [Embodiment] The following embodiments of the present invention are described by way of specific embodiments. Those skilled in the art can readily appreciate the advantages and advantages of the present invention from the disclosure herein. The present invention may be embodied or applied in various other specific embodiments, and the details of the present invention may be modified and changed based on the various aspects and applications without departing from the spirit and scope of the invention. Embodiment 1 Referring to Figure 2, there is shown a heat dissipation device in accordance with a preferred embodiment of the present invention.
如圖2所不’本實施例之散熱裝置包括：一外管41 ; 一 内管42，係設置於該外管41内，其中該内管42之内部空間 構成-第-腔體A，而内管4 2與外管4 i間之空間則構成一第 -腔體B ’且該内管42之兩端壁上具有複數個開孔42丄，以 使第-腔體A與第二腔體B互相連通；_毛細結構43(於本實 施例中’該毛細結構43為一銅網結構），係披覆於第二腔體 B之内壁（即，内管42之外壁與外管41之内壁）上；一磁性奈 米流體44，係填充於第一腔體A及第二腔體B中，其充填量 可約為30至50體積百分比，其中磁性奈米流體44包括一液 態流體441及複數個磁性奈米粒子442，而該些磁性奈米粒 子442之粒徑小於1 〇 nm，且其於液態流體44 i中之濃度約為 1.6xl(T2emu/g至8emu/g ; —磁場產生單元45，係設置於内 管42中。在此’第一腔體A包括傳輸流道A1及容置部A2， 且該散熱裝置之兩端分別作為蒸發部B1及冷凝部B2，其 中’傳輸流道A1係磁性奈米流體44與其蒸發氣體傳輸流動 之通道，而容置部A2係位於傳輸流道A1之外側，且用於容 置磁場產生單元45。 據此，請參見圖2，當外管41内壁上毛細結構43之磁性 奈米流體44因外管41被加熱而氣化時，高壓蒸氣會高速通 201226823 過該蒸發部B1處之開孔421而進入内管42，並同時推動内管 42外壁上毛細結構43之磁性奈米流體44，因此第一腔體a 之傳輸流道A1中會形成一小段氣體推一小段磁性奈米流體 之氣液相共存傳輸單元，而容置部八2之磁場產生單元45可 產生橫向穿過該傳輸流道A1之磁場（即，該磁場垂直於氣液 相傳輸單元傳輸方向），以增加局部磁場，提高傳輸單元中 磁性奈米流體44之熱傳導係數，其中，為提昇工作流體蒸 發量’蒸發部B1較佳係使用密度較密之毛細結構43;而後’ 當傳輸單元流至冷凝部B2時，磁性奈米流體44會先潤濕内 管42外壁上之毛細結構43，再藉由毛細力流至外管4丨内壁 上之毛細結構43，以進行熱交換冷凝，而蒸氣則通過冷凝 部B2處之開孔421與毛細結構43而進入冷凝部B2冷凝；最 後’冷凝後之磁性奈米流體44會流回至蒸發部b 1，並沖刷 蒸發時殘留於外管41内壁上毛細結構43之磁性奈米粒子 442，俾使磁性奈米粒子442流入内管42外壁上毛細結構43 之磁性奈米流體44中。 承上所述，本實施例所提供之散熱裝置主要結構特徵 在於：（1)内管之兩端具有複數個開孔（作用如喷嘴），其有 利於形成氣液相共存之傳輸單元’避免磁性奈米粒子留置 於蒸發部而導致熱阻上升之問題；（2)蒸發氣相及高溫液相 與冷凝液於不同流道流動。 實施例2 本實施例之散熱裝置與實施例1所述大致相同，惟不同 處在於，本實施例之磁場產生單元45係設置於内管42與外 12 201226823 管41之間。詳細地說，請參見圖3，於本實施例中，該第二 腔體B包括一容置部B3，其係位於内管42與外管41之間，且 該磁場產生單元45係設置於容置部B3中。 實施例3 本實施例之散熱裝置與實施例1所述大致相同，惟不同 處在於，如圖4所示，本實施例之磁場產生單元45係設置於 外管41之外侧。 實施例4 本實施例之散熱裝置與實施例1所述大致相同，惟不同 處在於，如圖5所示，本實施例之散熱裝置更包括：一感應 線圈46，係設置於該外管41之外圍。在此，該感應線圈46 可與一電力裝置51 (如風扇、USB、電池等）電性連接，以 提供電力予該電力裝置51。 實施例5 本實施例之散熱裝置與實施例3所述大致相同，惟不同 處在於，本實施例之傳輸流道係位於第二腔體中，而毛細 結構則係披覆於第一腔體之内壁上。 ^據此，當散熱裝置蒸發部中之磁性奈米流體被加熱而 氣化時，高壓蒸氣會推動磁性奈米流體，俾於第二腔體中 :成-小段氣體推-小段磁性奈米流體之氣液相共存傳輸 單元（亦即，本實施例之傳輸流道係位於第二腔體令），而設 置於外管外側之磁場產生單元可產生橫向穿過該傳輸流二 13 201226823 之磁場（即，該磁場垂直於氣液相傳輸單元傳輸方向），以增 加局部磁場，提高傳輸單元中磁性奈米流體之熱傳導係 數，其中，為提昇工作流體蒸發量，蒸發部較佳係使用密 度較密之毛細結構；而後，當傳輸單元流至冷凝部時，冷 凝後之液體會沿著内管内壁上之毛細結構流回至蒸發部， 並沖刷蒸發時殘留於蒸發部上毛細結構之磁性奈米粒子。 試驗例1 將佔裝置總體積之50體積百分比之水充填於習知單管 式熱管（如圖1A所示）中’而佔裝置總體積之50體積百分比 之磁性奈米流體（濃度約為8emu/g)充填於具有喷嘴結構且 蒸發氣相/高溫液相與冷凝液於不同流道流動之散熱裝置 中，於20W至60W之熱傳功率下比較熱阻，其結果如圖6所 不。其中，RMF係指具有喷嘴結構之散熱裝置充填磁性奈米 流趙之熱阻，Rwater則係指單管式熱管充填水之熱阻此外， 該磁f生奈米流體係使用水及粒控小於1 〇 nm之四氧化三鐵 奈米粒子分別作為液態流體及磁性奈米粒子。 如圊6所示，充填磁性奈米流體之散熱裝置的熱阻皆小 於充填水之散熱裝置的熱阻。由此可知，將磁性奈米流體 充填於本發明具有喷嘴結構且蒸發氣相/高溫液相與冷凝 液於不同流道流動之散熱裝置中確實可展現較佳之熱傳導 效果。 試驗例2 201226823 分別將不同濃度之磁性奈米流體（濃度約為h6xl〇_2 emu/g與4 emu/g)充填於具有喷嘴結構之散熱裝置中，並於 不同外加磁場強度下，與水充填於習知單管式熱管（如圖1A 所不）中之熱傳導係數進行比較，其結果如圖7所示。其中， KMF係指具有噴嘴結構之散熱裝置充填磁性奈米流體之熱 傳導係數，指單管式熱管充填水之熱傳導係數。此 外’該磁性奈米流體係使用水及粒徑小 於10 nm之四氧化三 % 鐵奈米粒子分別作為液態流體及磁性奈米粒子。如圖78所 不，磁場強度為1000 Oe至3000 〇6時，充填磁性奈米流體 之散熱裝置的熱傳導係數優於充填水之散熱裝置，而磁性 奈米流體濃度為4 emu/g且磁場強度為2000 〇e時則可展現 最佳之熱傳導性質，其熱傳導係數約為水的3 7倍。 【圖式簡單說明】 圖1A係習知單管式熱管之示意圖。 聲圖1B係習知迴路式熱管之示意圖。 圖1C係習知迴路脈衝式熱管之示意圖。 圖2係本發明一較佳實施例之散熱裝置示意圖。 圖3係本發明另一較佳實施例之散熱裝置示意圖。 圖4係本發明另一較佳實施例之散熱裝置示意圖。 圖5係本發明另一較佳實施例之散熱裝置示意圖。 圖6係具有喷嘴結構之散熱裝置充填磁性奈米流體及單管 式熱管充填水於不同熱傳功率下之熱阻比較圖。 15 201226823 圖7係具有喷嘴結構之散熱裝置充填不同濃度磁性奈米流 體及單管式熱管充填水於不同磁場強度下之熱傳導係數比 較圖。 主要 $件符號說明 封閉管體 13, 43 毛細結構 工作流體 21 封閉式迴路管 多迴路式管體 41 外管 内管 421 開孑L 磁性奈米流體 441 液態流體 磁性奈米粒子 45 磁場產生單元 感應線圈 51 電力裝置 第一腔體 A1 傳輸流道 容置部 B 第二腔體 蒸發部 B2 冷凝部 14> 24,34 31 42 44 442 46 Λ Α2, Β3 BlAs shown in FIG. 2, the heat dissipating device of the present embodiment includes: an outer tube 41; an inner tube 42 disposed in the outer tube 41, wherein the inner space of the inner tube 42 constitutes a - cavity A, and The space between the inner tube 4 2 and the outer tube 4 i constitutes a first cavity B ' and the end walls of the inner tube 42 have a plurality of openings 42 以 so that the first cavity A and the second cavity The body B is in communication with each other; the capillary structure 43 (in the present embodiment, the capillary structure 43 is a copper mesh structure) is coated on the inner wall of the second cavity B (ie, the outer wall of the inner tube 42 and the outer tube 41) On the inner wall), a magnetic nanofluid 44 is filled in the first cavity A and the second cavity B, and the filling amount thereof may be about 30 to 50 volume percent, wherein the magnetic nano fluid 44 includes a liquid fluid 441 and a plurality of magnetic nanoparticles 442 having a particle size of less than 1 〇 nm and a concentration of about 1.6 x 1 in the liquid fluid 44 i (T2emu/g to 8 emu/g; The magnetic field generating unit 45 is disposed in the inner tube 42. Here, the first cavity A includes the transport flow path A1 and the accommodating portion A2, and the two ends of the heat dissipating device serve as the evaporation portion B, respectively. 1 and a condensing portion B2, wherein 'the transport flow path A1 is a passage through which the magnetic nano-fluid 44 and the evaporating gas are transported, and the accommodating portion A2 is located on the outer side of the transport flow path A1 and is for accommodating the magnetic field generating unit 45. Accordingly, referring to FIG. 2, when the magnetic nanofluid 44 of the capillary structure 43 on the inner wall of the outer tube 41 is vaporized by the heating of the outer tube 41, the high-pressure vapor will pass through the opening 421 at the evaporation portion B1 at high speed through 201226823. While entering the inner tube 42 and simultaneously pushing the magnetic nanofluid 44 of the capillary structure 43 on the outer wall of the inner tube 42, a small gas is formed in the transport channel A1 of the first chamber a to push a small amount of magnetic nanofluid gas. The liquid phase coexists with the transport unit, and the magnetic field generating unit 45 of the accommodating portion VIII can generate a magnetic field transversely passing through the transport channel A1 (ie, the magnetic field is perpendicular to the transport direction of the gas-liquid transport unit) to increase the local magnetic field. Increasing the heat transfer coefficient of the magnetic nanofluid 44 in the transport unit, wherein in order to increase the evaporation amount of the working fluid, the evaporating portion B1 preferably uses a denser capillary structure 43; and then when the transport unit flows to the condensing portion B2, the magnetic Nai The rice fluid 44 first wets the capillary structure 43 on the outer wall of the inner tube 42 and then flows to the capillary structure 43 on the inner wall of the outer tube 4 by capillary force for heat exchange condensation, and the vapor passes through the condensation portion B2. The opening 421 and the capillary structure 43 enter the condensation portion B2 to condense; finally, the 'condensed magnetic nano-fluid 44 flows back to the evaporation portion b1, and rushes to the magnetic nano-residue of the capillary structure 43 remaining on the inner wall of the outer tube 41 during evaporation. The rice particles 442 are caused to flow into the magnetic nano-fluids 44 of the capillary structure 43 on the outer wall of the inner tube 42. As described above, the main structural features of the heat dissipating device provided in this embodiment are: (1) The two ends of the tube have a plurality of openings (acting as nozzles), which are favorable for forming a gas-liquid phase coexisting transmission unit 'to avoid the problem that the magnetic nanoparticles are left in the evaporation portion and cause the thermal resistance to rise; (2) evaporating the gas phase And the high temperature liquid phase and the condensate flow in different flow channels. Embodiment 2 The heat sink of this embodiment is substantially the same as that described in Embodiment 1, except that the magnetic field generating unit 45 of the present embodiment is disposed between the inner tube 42 and the outer 12 201226823 tube 41. In detail, referring to FIG. 3, in the embodiment, the second cavity B includes a receiving portion B3 between the inner tube 42 and the outer tube 41, and the magnetic field generating unit 45 is disposed on In the housing portion B3. Embodiment 3 The heat sink of this embodiment is substantially the same as that described in Embodiment 1, except that, as shown in Fig. 4, the magnetic field generating unit 45 of the present embodiment is disposed on the outer side of the outer tube 41. The heat dissipating device of the embodiment is substantially the same as that of the first embodiment, except that, as shown in FIG. 5, the heat dissipating device of the embodiment further includes: an induction coil 46 disposed on the outer tube 41. The periphery. Here, the induction coil 46 can be electrically connected to a power device 51 (such as a fan, USB, battery, etc.) to provide power to the power device 51. Embodiment 5 The heat dissipating device of this embodiment is substantially the same as that described in Embodiment 3, except that the transport channel of the embodiment is located in the second cavity, and the capillary structure is coated on the first cavity. On the inside wall. According to this, when the magnetic nanofluid in the evaporation portion of the heat sink is heated and vaporized, the high pressure vapor pushes the magnetic nanofluid into the second cavity: a small-segment gas push-small magnetic nanofluid The gas-liquid phase coexisting transfer unit (that is, the transport flow path of the present embodiment is located in the second cavity), and the magnetic field generating unit disposed outside the outer tube can generate a magnetic field transversely passing through the transport stream 2 201226823 (ie, the magnetic field is perpendicular to the transport direction of the gas-liquid phase transport unit) to increase the local magnetic field and increase the heat transfer coefficient of the magnetic nanofluid in the transport unit. Among them, in order to increase the evaporation amount of the working fluid, the evaporation portion is preferably used at a higher density. a dense capillary structure; then, when the transfer unit flows to the condensing portion, the condensed liquid flows back to the evaporation portion along the capillary structure on the inner wall of the inner tube, and scoured the magnetic nano-residue remaining on the evaporation portion during evaporation Rice particles. Test Example 1 50% by volume of water, based on the total volume of the apparatus, was filled in a conventional single-tube heat pipe (as shown in Fig. 1A) to account for 50% by volume of the total volume of the magnetic nanofluid (concentration was about 8 emu). /g) Filling in a heat sink having a nozzle structure and evaporating gas phase/high temperature liquid phase and condensate flowing in different flow paths, the thermal resistance is compared under a heat transfer power of 20 W to 60 W, and the result is shown in Fig. 6. Among them, RMF refers to the thermal resistance of the heat sink filled with the nozzle structure, and Rwater refers to the thermal resistance of the single-tube heat pipe filling water. In addition, the magnetic f-nano flow system uses water and the particle control is smaller than 1 〇 nm of ferroferric oxide nanoparticles are used as liquid fluids and magnetic nanoparticles, respectively. As shown in Figure 6, the thermal resistance of the heat sink filled with magnetic nanofluids is less than the thermal resistance of the heat sink filling the water. From this, it can be seen that the magnetic nanofluid is filled in the heat dissipating device having the nozzle structure of the present invention and the evaporating gas phase/high temperature liquid phase and the condensate flowing in different flow paths can surely exhibit a better heat conduction effect. Test Example 2 201226823 Different concentrations of magnetic nanofluids (concentrations of about h6xl〇_2 emu/g and 4 emu/g) were respectively filled in a heat sink having a nozzle structure, and under different applied magnetic field strengths, with water The heat transfer coefficients in a conventional single-tube heat pipe (not shown in Fig. 1A) were compared, and the results are shown in Fig. 7. Among them, KMF refers to the heat transfer coefficient of the magnetic nano-fluid filled with the heat sink of the nozzle structure, and refers to the heat transfer coefficient of the single-tube heat pipe filling water. Further, the magnetic nano-flow system uses water and 3% of iron oxide nanoparticles having a particle diameter of less than 10 nm as liquid fluid and magnetic nanoparticles, respectively. As shown in Fig. 78, when the magnetic field strength is 1000 Oe to 3000 〇6, the heat transfer coefficient of the heat sink filled with magnetic nano fluid is better than that of the water filling device, and the magnetic nano fluid concentration is 4 emu/g and the magnetic field strength The best thermal conductivity is 2000 〇e, and its thermal conductivity is about 37 times that of water. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a schematic view of a conventional single tube heat pipe. Acoustic diagram 1B is a schematic diagram of a conventional loop type heat pipe. Figure 1C is a schematic diagram of a conventional loop pulse type heat pipe. 2 is a schematic view of a heat sink according to a preferred embodiment of the present invention. 3 is a schematic view of a heat sink according to another preferred embodiment of the present invention. 4 is a schematic view of a heat sink according to another preferred embodiment of the present invention. FIG. 5 is a schematic diagram of a heat sink according to another preferred embodiment of the present invention. Fig. 6 is a comparison diagram of thermal resistance of a heat sink filled with a nozzle structure and filled with a magnetic nanofluid and a single-tube heat pipe filling water at different heat transfer powers. 15 201226823 Figure 7 is a heat transfer coefficient comparison diagram of a heat sink with a nozzle structure filled with different concentrations of magnetic nanofluids and a single-tube heat pipe filled with water at different magnetic field strengths. The main part symbol indicates the closed pipe body 13, 43 capillary structure working fluid 21 closed circuit pipe multi-circuit pipe body 41 outer pipe inner pipe 421 opening L magnetic nano fluid 441 liquid fluid magnetic nano particle 45 magnetic field generating unit induction coil 51 Power device first cavity A1 Transport flow path accommodating portion B Second cavity evaporation portion B2 Condensing portion 14> 24, 34 31 42 44 442 46 Λ Α2, Β3 Bl