JP5493949B2 - Heat transfer member and heat exchanger using the same - Google Patents

Description

  The present invention relates to a heat transfer member and a heat exchanger using the heat transfer member.

  Generally, a heat exchanger has a configuration in which a flow path for a high-temperature fluid and a flow path for a low-temperature fluid are separated from each other by a partition wall. For example, in a radiator, a flow path of cooling water that is a high-temperature fluid is formed inside the tube, and a flow path of air that is a low-temperature fluid is formed outside the tube (see, for example, Patent Document 1). The heat energy of the cooling water is transmitted to the tube by heat exchange on the inner wall surface of the tube, and further transferred to the air by heat exchange on the outer wall surface of the tube and the fin surface. As described above, in the heat exchanger, heat energy is transmitted by heat exchange between the two layers at the interface between the solid layer and the fluid layer.

JP 2008-267693 A

The transfer of thermal energy between the solid layer and the fluid layer as described above is caused by the propagation of one thermal vibration to the other due to the interaction between the surface atoms of the solid layer and the molecules of the fluid layer. . Propagation of thermal vibration between the two layers is more likely to occur as the thermal vibration frequencies of both layers are closer to each other. FIG. 8 is a graph showing an example of the frequency distribution of thermal vibration in each of the surface atoms of the solid layer (metal) and the molecules of the fluid layer (liquid). As shown in FIG. 8, the frequency distribution peak (10 ¹² Hz order) of the solid thermal vibration and the frequency distribution peak (10 ⁹ Hz order) of the liquid thermal vibration are compared with the width of each distribution. Is greatly different. For this reason, the portions where the respective vibration frequency distributions overlap each other are extremely small (part K in FIG. 8). Therefore, at the solid-liquid interface, it is difficult for thermal vibrations to propagate between the solid layer and the liquid layer, so that there is a problem that the thermal energy to be transmitted is attenuated. Further, since the thermal vibration frequency of the gas is almost the same order as the vibration frequency of the liquid, there is a problem that the thermal energy to be transmitted is attenuated at the solid-gas interface as well.

  An object of the present invention is to provide a heat transfer member capable of efficiently transferring heat energy between a solid layer and a fluid layer, and a heat exchanger using the heat transfer member.

  In order to achieve the above object, the present invention employs the following technical means.

  According to the first aspect of the present invention, the solid layer (70) that exchanges heat with the fluid layer (80) at the interface (75) with the fluid layer (80), and the solid layer (70) provided at the interface (75). ) And the vibration body (92) capable of propagating thermal vibration between the surface atoms and the molecules of the fluid layer (80), and the elasticity for elastically supporting the vibration body (92) with respect to the solid layer (70). A vibrator (90) including a support portion (91), and the vibration frequency peak (Wv) of the vibrator (90) is greater than the vibration frequency peak (Wl) of the molecules of the fluid layer (80). The heat transfer member is characterized in that it is higher than the peak (Ws) of the vibration frequency of the surface atoms of the solid layer (70).

  According to this, thermal vibration can be indirectly propagated between the solid layer (70) and the fluid layer (80) via the vibrator (90). The vibration frequency peak (Wv) of the vibrator (90) is between the vibration frequency peak (Ws) of the surface atoms of the solid layer (70) and the vibration frequency peak (Wl) of the molecules of the fluid layer (80). Exists. Thereby, since the overlapping part of the vibration frequency distribution of the solid layer (70) and the vibration frequency distribution of the vibrator (90) can be enlarged, the solid layer (70) and the vibrator (90) can be overlapped. Attenuation of thermal energy can be suppressed. Moreover, since the overlapping part of the vibration frequency distribution of the vibrator (90) and the vibration frequency distribution of the fluid layer (80) can be enlarged, the heat between the vibrator (90) and the fluid layer (80) can be increased. Energy attenuation can be suppressed. Therefore, heat energy can be efficiently transferred between the solid layer (70) and the fluid layer (80) via the vibrator (90).

Further, in the first aspect of the invention, the vibrator (90) includes a first vibrator (100) and a second vibrator (110), and the first vibrator (100) is a solid layer ( 170) and thermal vibrations are propagated between the molecules of the fluid layer (180) via the second vibrator (110) and the second vibrator (110). ) Propagates thermal vibration between the molecules of the fluid layer (180) and thermal vibration between the surface atoms of the solid layer (170) via the first vibrator (100), The vibration frequency peak (Wv2) of the first vibrator (100) is higher than the vibration frequency peak (Wv1) of the second vibrator (110).

  According to this, thermal vibration can be indirectly propagated between the solid layer (170) and the fluid layer (180) via the first vibrator (100) and the second vibrator (110). The vibration frequency peak (Wv2) of the first vibrator (100) and the vibration frequency peak (Wv1) of the second vibrator (110) are both peaks (Ws) of the vibration frequency of the surface atoms of the solid layer (170). ) And the vibration frequency peak (Wl) of the molecule of the fluid layer (180), and the vibration frequency peak (Wv2) of the first vibrator (100) is the same as that of the second vibrator (110). It is higher than the peak (Wv1) of the vibration frequency. Thereby, since the overlapping part of the vibration frequency distribution of the solid layer (170) and the vibration frequency distribution of the first vibrator (100) can be enlarged, the solid layer (170) and the first vibrator (100) Attenuation of thermal energy between the two can be suppressed. Moreover, since the overlapping part of the vibration frequency distribution of the first vibrator (100) and the vibration frequency distribution of the second vibrator (110) can be enlarged, the first vibrator (100) and the second vibrator ( 110), the attenuation of thermal energy can be suppressed. Furthermore, since the overlapping part of the vibration frequency distribution of the second vibrator (110) and the vibration frequency distribution of the fluid layer (180) can be enlarged, the second vibrator (110) and the fluid layer (180) Attenuation of thermal energy between the two can be suppressed. Therefore, thermal energy can be efficiently transferred between the solid layer (170) and the fluid layer (180) via the first vibrator (100) and the second vibrator (110).

The invention according to claim 2 is a heat exchanger characterized in that the heat transfer member of the invention is used. Thereby, the heat exchanger which can transfer a thermal energy efficiently between a solid layer (70) and a fluid layer (80) is obtained.

  In addition, the code | symbol in the bracket | parenthesis of each said means has shown an example of the corresponding relationship with the specific means as described in embodiment mentioned later.

It is a figure which shows the whole structure of the heat exchanger in 1st Embodiment. It is a figure which shows typically the structure of the solid-liquid interface formed in a flat tube in the heat exchanger of 1st Embodiment. It is a graph which shows an example of the frequency distribution of the thermal vibration in each of the surface atom of a solid layer, the molecule | numerator of a liquid layer, and a vibrator | oscillator. It is a graph which shows an example of the relationship between the length of one side of a vibrating body, and the vibration frequency of a vibrator | oscillator. It is a figure which shows typically the structure of the solid-liquid interface formed in a flat tube in the heat exchanger of 2nd Embodiment. It is a graph which shows an example of the frequency distribution of the thermal vibration in each of the surface atom of a solid layer, the molecule | numerator of a liquid layer, and a high frequency vibrator and a low frequency vibrator. It is a graph which shows an example of the relationship between the length of one side of a vibrating body, and the vibration frequency of a vibrator | oscillator. It is a graph which shows the example of the vibration frequency distribution of the thermal vibration in each of a solid surface atom and a liquid molecule.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an overall configuration of a radiator 1 as a heat exchanger in the present embodiment. As shown in FIG. 1, the radiator 1 includes a metal core portion 40 that cools engine coolant by heat exchange with air, and a pair of tanks 52 and 62 made of, for example, resin attached to the core portion 40. doing. The tank 52 is provided with an inlet 53 through which engine cooling water flows from the outside, and the tank 62 is provided with an outlet 63 through which engine cooling water flows out.

  The core portion 40 extends in a substantially vertical direction, and a plurality of flat tubes 10 through which engine coolant flows, and a plurality of corrugated fins 30 that are thermally connected to the flat tubes 10 and increase a heat transfer area for air. And are alternately stacked. The flat tube 10 and the corrugated fin 30 are configured by a predetermined heat transfer member. The inner peripheral surface of the flat tube 10 becomes a solid-liquid interface between the heat transfer member and the engine coolant, and the outer peripheral surface of the flat tube 10 and the surface of the corrugated fin 30 become a solid-gas interface between the heat transfer member and air.

  A core plate 51 that constitutes the upper header 50 together with the tank 52 is provided on the upper end side of the core portion 40. A core plate 61 that constitutes the lower header 60 together with the tank 62 is provided at the lower end side of the core portion 40. A plurality of insertion holes are formed in each of the core plates 51 and 61, and the distal ends of the flat tubes 10 are inserted into the insertion holes. The upper header 50 and the lower header 60 communicate with each other via a plurality of flat tubes 10.

  FIG. 2 schematically shows a solid-liquid interface formed inside the flat tube 10 as a configuration of the heat transfer member of the present embodiment. As shown in FIG. 2, in the vicinity of the solid-liquid interface 75 (inner surface of the flat tube 10) between the solid layer 70 (flat tube 10) and the liquid layer 80 (engine cooling water), the solid layer 70 and the liquid layer 80. A plurality of minute vibrators (thermal noise actuators) 90 whose vibrations are excited by thermal noise from both sides are provided (only one vibrator 90 is shown in FIG. 2). The vibrator 90 includes a vibrating body 92 that vibrates at a predetermined vibration frequency and an elastic support portion 91 that elastically supports the vibrating body 92 with respect to the solid layer 70.

  The vibrating body 92 is made of alumina nanoparticles, for example, and has a substantially cubic shape with a side of 1 nm. The vibrating body 92 is disposed closer to the liquid layer 80 than the solid-liquid interface 75, and is close to the solid-liquid interface 75 via a predetermined gap.

  The elastic support portion 91 is formed of, for example, carbon nanotubes, has a linear shape (bar shape), and has rigidity like a spring. One end portion 91 a of the elastic support portion 91 is a fixed end fixed to the surface of the solid layer 70. The other end portion 91 b of the elastic support portion 91 is a free end and is connected to the vibrating body 92. The elastic support portion 91 extends obliquely with respect to the surface of the solid layer 70.

Here, an example of a method for fixing the vibrator 90 to the surface of the solid layer 70 will be described. First, powdery C ₆₀ fullerene is applied to the surface of the solid layer 70 and predetermined portions of the vibrating body 92, and the one end 91 a and the other end 91 b of the elastic support portion 91 are brought into contact with the applied C ₆₀ fullerene, respectively. In this state, when the C ₆₀ fullerene is irradiated with an electron beam, the C ₆₀ fullerene changes to graphite, and due to this structural change, between the surface of the solid layer 70 and the one end 91a, and between the vibrating body 92 and the other end 91b. Each space is fixed. Thereby, the vibrator 90 can be fixed to the surface of the solid layer 70.

  As indicated by a double arrow A in FIG. 2, thermal vibration can be directly propagated between surface atoms (not shown) of the solid layer 70 and the vibrating body 92 by an interaction such as intermolecular force. ing. Further, as indicated by a double arrow B, thermal vibration can be directly propagated between the vibrating body 92 and the liquid molecules (not shown) of the liquid layer 80 by an interaction such as intermolecular force. . That is, thermal vibration can be indirectly propagated between the surface atoms of the solid layer 70 and the molecules of the liquid layer 80 via the vibrating body 92.

The vibration frequency W of the vibrator 90 is obtained by using the mass M of the vibrating body 92 and the spring constant K of the elastic support portion 91.
W = √ (K / M)
It is expressed. However, the mass of the elastic support 91 is sufficiently smaller than the mass M of the vibrating body 92. In addition, the vibration frequency W of the vibrator 90 is obtained by using the length r and the density ρ of one side of the vibrator 92 when the shape of the vibrator 92 is a cube.
W = √ (K / ρr ³ )
It is expressed. As described above, the vibration frequency W of the vibrator 90 can be adjusted relatively easily by changing the mass M (density ρ and length r of one side) of the vibrator 92 and the spring constant K of the elastic support portion 91. .

FIG. 3 is a graph showing an example of the frequency distribution of thermal vibration in each of the surface atoms of the solid layer 70, the molecules of the liquid layer 80, and the vibrator 90 according to this embodiment. The horizontal axis of the graph represents the vibration frequency (Hz) in logarithm, and the vertical axis represents the occurrence frequency. As shown in FIG. 3, the surface atoms of the solid layer 70, the molecules of the liquid layer 80, and the vibration frequency of the thermal vibration of the vibrator 90 all follow a predetermined distribution. The vibration frequency peak Wl of the molecules in the liquid layer 80 is generally several GHz (on the order of 10 ⁹ Hz), and the vibration frequency peak Ws of the surface atoms of the solid layer 70 is generally several THz (on the order of 10 ¹² Hz). The vibration frequency peak Wv of the vibrator 90 is set to be higher than the vibration frequency peak Wl of the liquid layer 80 and lower than the vibration frequency peak Ws of the solid layer 70 (Wl <Wv <Ws). . Thereby, the overlapping part (C portion in the figure) of the vibration frequency distribution of the solid layer 70 and the vibration frequency distribution of the vibrator 90, and the overlapping part of the vibration frequency distribution of the vibrator 90 and the vibration frequency distribution of the liquid layer 80. (D part) can be enlarged compared with the overlapping part (K part) shown in FIG.

  In general, the vibration frequency Ws of the solid layer 70 is about 1000 times the vibration frequency Wl of the liquid layer 80. For this reason, in order to enlarge the overlapping part of the vibration frequency distribution of the vibrator 90 and both the vibration frequency distribution of the solid layer 70 and the vibration frequency distribution of the liquid layer 80, the vibration frequency Wv of the vibrator 90 is Desirably, the vibration frequency Wl of the layer 80 is approximately 10 to 100 times (several tens of GHz to several hundreds of GHz).

FIG. 4 is a graph showing an example of the relationship between the length of one side of the cubical vibrator 92 and the vibration frequency of the vibrator 90. The horizontal axis of the graph represents the length r (m) of one side of the vibrating body 92 as a logarithm, and the vertical axis represents the vibration frequency (Hz) as a logarithm. The line L1 indicates the vibration frequency of the vibrator 90, the line L2 indicates the vibration frequency Ws of the surface atoms of the solid layer 70, and the line L3 indicates the vibration frequency Wl of the molecules in the liquid layer 80. In this example, the density ρ of the vibrating body 92 is 2.7 × 10 ³ kg / m ³ , the spring constant K of the elastic support portion 91 is 0.1 N / m, and the vibration frequency Ws of the surface atoms of the solid layer 70 is 7 THz, and the vibration frequency W1 of the molecules of the liquid layer 80 was 1 GHz.

As shown in FIG. 4, the vibration frequency Wv of the vibrator 90 becomes higher as the length r of one side of the vibrating body 92 becomes smaller, and when the length r of one side is about 1 × 10 ⁻⁸ m, the liquid layer 80. Is equal to the vibration frequency. When the length r of one side is less than that, the vibration frequency Wv of the vibrator 90 becomes higher than the vibration frequency of the liquid layer 80. On the other hand, considering the size of the constituent molecules or constituent atoms of the vibrating body 92, the practical lower limit of the length r of one side is on the order of 10 ⁻¹⁰ to 10 ⁻⁹ m. Even if the length r of one side is reduced to this lower limit, the vibration frequency Wv of the vibrator 90 is lower than the vibration frequency Ws of the solid layer 70. That is, in the case of the condition of this example, in order to satisfy the relationship of Wl <Wv <Ws, the length r of one side of the vibrating body 92 may be less than about 1 × 10 ⁻⁸ m, and the length r of one side There is virtually no need to consider the lower limit.

  As described above, according to the present embodiment, thermal energy can be indirectly propagated between the solid layer 70 and the liquid layer 80 via the vibrator 90. The vibration frequency peak Wv of the vibrator 90 exists between the vibration frequency peak Ws of the surface atoms of the solid layer 70 and the vibration frequency peak Wl of the molecules of the liquid layer 80. Thereby, since the overlapping part of the vibration frequency distribution of the solid layer 70 and the vibration frequency distribution of the vibrator 90 can be enlarged, the attenuation when heat energy is transferred between the solid layer 70 and the vibrator 90 is reduced. Can be suppressed. In addition, since an overlapping portion between the vibration frequency distribution of the vibrator 90 and the vibration frequency distribution of the liquid layer 80 can be enlarged, attenuation when heat energy is transmitted between the vibrator 90 and the liquid layer 80 is suppressed. be able to. Therefore, heat energy can be efficiently transmitted between the solid layer 70 and the liquid layer 80 via the vibrator 90. That is, according to the present embodiment, high heat exchange performance is obtained in the heat exchanger, and high cooling performance is obtained in the case of the radiator 1 that cools the engine coolant.

  In the present embodiment, the vibrator 90 includes a vibrating body 92 and an elastic support portion 91. Thereby, the vibration frequency of the vibrator 90 can be easily adjusted by changing the mass M of the vibrating body 92 and the spring constant K of the elastic support portion 91. Therefore, the vibration frequency peak Wv of the vibrator 90 can be easily set between the vibration frequency peak Wl of the liquid layer 80 and the vibration frequency peak Ws of the solid layer 70.

  In the present embodiment, in order to cause a predetermined interaction between the surface atoms of the solid layer 70 and the vibrating body 92 of the vibrator 90, it is necessary to bring the surface of the solid layer 70 and the vibrating body 92 close to each other. On the other hand, in order to lower the vibration frequency of the vibrator 90 and approach the vibration frequency of the liquid layer 80, it is effective to lengthen the elastic support portion 91 and reduce the spring constant K. In the present embodiment, since the elastic support portion 91 extends obliquely with respect to the surface of the solid layer 70, the length of the elastic support portion 91 is increased while bringing the surface of the solid layer 70 and the vibrator 92 close to each other. It becomes easy.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 schematically shows a solid-liquid interface formed inside the flat tube 10 as a configuration of the heat transfer member of the present embodiment. As shown in FIG. 5, a solid-liquid interface 175 between the solid layer 170 (flat tube 10) and the liquid layer 180 (engine cooling water) includes a plurality of high-frequency vibrators (first vibrators) 100 and a plurality of low A frequency vibrator (second vibrator) 110 is provided (only one high-frequency vibrator 100 and one low-frequency vibrator 110 are shown in FIG. 5).

  The high-frequency vibrator 100 includes a vibrating body 102 that vibrates at a predetermined vibration frequency and an elastic support portion 101 that elastically supports the vibrating body 102 with respect to the solid layer 170. The vibrating body 102 is formed of alumina nanoparticles, for example, and has a substantially cubic shape with a side of 0.5 nm. The vibrating body 102 is disposed close to the surface of the solid layer 170 via a predetermined gap. The elastic support portion 101 is formed of, for example, carbon nanotubes, has a linear shape, and has rigidity like a spring. One end portion 101 a of the elastic support portion 101 is a fixed end fixed to the surface of the solid layer 170. The other end portion 101 b of the elastic support portion 101 is a free end and is connected to the vibrating body 102.

  The low-frequency vibrator 110 includes a vibrating body 112 that vibrates at a predetermined vibration frequency and an elastic support portion 111 that elastically supports the vibrating body 112 with respect to the solid layer 170. The vibrating body 112 is made of alumina nanoparticles, for example, and has a substantially cubic shape with a side of 1 nm larger than the vibrating body 102. The vibrating body 112 is disposed in the vicinity of the vibrating body 102. The vibrating body 102 is located between the vibrating body 112 and the surface of the solid layer 170, and the vibrating body 112 and the solid layer 170 are relatively separated from each other. The elastic support portion 111 is formed of, for example, carbon nanotubes, has a linear shape longer than the elastic support portion 101, and has rigidity like a spring. One end portion 111 a of the elastic support portion 111 is a fixed end fixed to the surface of the solid layer 170. The other end 111 b of the elastic support 111 is a free end and is connected to the vibrating body 112.

  As indicated by a double-headed arrow E in FIG. 5, thermal vibration can be directly propagated between the surface atoms of the solid layer 170 and the vibrating body 102 of the high-frequency vibrator 100 by interaction such as intermolecular force. ing. Further, as indicated by a double arrow F, thermal vibration can be directly propagated between the vibrating body 102 of the high-frequency vibrator 100 and the vibrating body 112 of the low-frequency vibrator 110 by an interaction such as intermolecular force. It has become. Further, as indicated by a double arrow G, thermal vibration can be directly propagated between the vibrating body 112 of the low-frequency vibrator 110 and the molecules of the liquid layer 180 by an interaction such as intermolecular force. . That is, thermal vibration can be indirectly propagated between the surface atoms of the solid layer 170 and the molecules of the liquid layer 180 via the high-frequency vibrator 100 and the low-frequency vibrator 110.

The vibration frequency W1 of the low frequency vibrator 110 is obtained by using the mass M1 of the vibrating body 112 and the spring constant K1 of the elastic support portion 111.
W1 = √ (K1 / M1)
It is expressed. However, the mass of the elastic support portion 111 is sufficiently smaller than the mass M1 of the vibrating body 112. Further, the vibration frequency W1 of the low frequency vibrator 110 is obtained by using the length r1 and the density ρ1 of one side of the vibrating body 112 when the shape of the vibrating body 112 is a cubic shape.
W1 = √ (K1 / (ρ1 × r1 ³ ))
It is expressed. As described above, the vibration frequency W1 of the low-frequency vibrator 110 is relatively easily adjusted by changing the mass M1 (density ρ1 and length r1 of one side) of the vibrating body 112 and the spring constant K1 of the elastic support 111. It can be done.

The vibration frequency W2 of the high-frequency vibrator 100 is obtained by using the mass M2 of the vibrating body 102 and the spring constant K2 of the elastic support portion 101.
W2 = √ (K2 / M2)
It is expressed. However, it is assumed that the mass of the elastic support portion 101 is sufficiently smaller than the mass M2 of the vibrating body 102. The vibration frequency W2 of the high-frequency vibrator 100 is obtained by using the length r2 and the density ρ2 of one side of the vibration body 102 when the shape of the vibration body 102 is a cubic shape.
W2 = √ (K2 / (ρ2 × r2 ³ ))
It is expressed. Thus, the vibration frequency W2 of the high-frequency vibrator 100 can be adjusted relatively easily by changing the mass M2 (density ρ2 and length r2 of one side) of the vibrating body 102 and the spring constant K2 of the elastic support portion 101. It is like that.

  FIG. 6 is a graph showing an example of the frequency distribution of thermal vibration in each of the surface atoms of the solid layer 170, the molecules of the liquid layer 180, the high-frequency vibrator 100, and the low-frequency vibrator 110. The horizontal axis of the graph represents the vibration frequency (Hz) in logarithm, and the vertical axis represents the occurrence frequency. As shown in FIG. 6, the frequency distribution of the thermal vibrations of the surface atoms of the solid layer 170, the molecules of the liquid layer 180, the high-frequency vibrator 100, and the low-frequency vibrator 110 all follow a predetermined distribution. The vibration frequency peak Wv1 of the low-frequency vibrator 110 and the vibration frequency peak Wv2 of the high-frequency vibrator 100 are both higher than the vibration frequency peak Wl of the liquid layer 180 and higher than the vibration frequency peak Ws of the solid layer 170. Is set to be low. The vibration frequency peak Wv2 of the high-frequency vibrator 100 is set to be higher than the vibration frequency peak Wv1 of the low-frequency vibrator 110 (Wl <Wv1 <Wv2 <Ws).

  Thereby, the overlapping part (H part in the figure) of the vibration frequency distribution of the solid layer 170 and the vibration frequency distribution of the high frequency vibrator 100, the vibration frequency distribution of the high frequency vibrator 100 and the vibration frequency distribution of the low frequency vibrator 110 3 and the overlapping part (J part) of the vibration frequency distribution of the low-frequency vibrator 110 and the vibration frequency distribution of the liquid layer 180 are the overlapping part (C) of the first embodiment shown in FIG. Part, part D) and can be further enlarged.

FIG. 7 shows an example of the relationship between the length of one side of the vibrating body 112 and the vibration frequency of the high-frequency vibrator 100 and the low-frequency vibrator 110 when the length of one side of the vibrating body 102 is half that of the vibrating body 112. It is a graph to show. The horizontal axis of the graph represents the length r (m) of one side of the vibrating body 112 in logarithm, and the vertical axis represents the vibration frequency (Hz) in logarithm. A line L4 indicates the vibration frequency of the high-frequency vibrator 100, a line L5 indicates the vibration frequency of the low-frequency vibrator 110, a line L6 indicates the vibration frequency Ws of the surface atoms of the solid layer 170, and a line L7 indicates the liquid layer 180. The vibration frequency Wl of the molecule is shown. In this example, the density ρ1 and ρ2 of the vibrating bodies 112 and 102 are both 2.7 × 10 ³ kg / m ^3, and the spring constants K1 and K2 of the elastic support portions 111 and 101 are both 0.1 N / m. The vibration frequency Ws of the surface atoms of the solid layer 170 was 7 THz, and the vibration frequency Wl of the molecules of the liquid layer 180 was 1 GHz.

As shown in FIG. 7, the vibration frequency of the low-frequency vibrator 110 exceeds the vibration frequency of the liquid layer 180 when the length r of one side of the vibration body 112 is less than about 1 × 10 ⁻⁸ m. On the other hand, even if the length r of one side of the vibrating body 112 (twice the length of one side of the vibrating body 102) is reduced to a practical lower limit (10 ⁻¹⁰ to 10 ⁻⁹ m order), the high-frequency vibrator 100 Is less than the vibration frequency Ws of the solid layer 70. Therefore, in the case of the conditions of this example, in order to satisfy the relationship of Wl <Wv1 <Wv2 <Ws, the length r of one side of the vibrating body 112 may be less than about 1 × 10 ⁻⁸ m.

  As described above, according to the present embodiment, thermal energy can be indirectly transmitted between the solid layer 170 and the liquid layer 180 via the high-frequency vibrator 100 and the low-frequency vibrator 110. The vibration frequency peak Wv2 of the high frequency vibrator 100 and the vibration frequency peak Wv1 of the low frequency vibrator 110 are relative to the vibration frequency peak Ws of the surface atoms of the solid layer 170 and the vibration frequency peak Wl of the molecules of the liquid layer 180. Thus, the relationship of Wl <Wv1 <Wv2 <Ws is set.

  Thereby, since the overlapping part of the vibration frequency distribution of the solid layer 170 and the vibration frequency distribution of the high frequency vibrator 100 can be enlarged, the heat energy is transferred between the solid layer 170 and the high frequency vibrator 100. Attenuation can be suppressed. In addition, since the overlapping portion of the vibration frequency distribution of the high frequency vibrator 100 and the vibration frequency distribution of the low frequency vibrator 110 can be enlarged, heat energy is transmitted between the high frequency vibrator 100 and the low frequency vibrator 110. Attenuation can be suppressed. Furthermore, since the overlapping part of the vibration frequency distribution of the low frequency vibrator 110 and the vibration frequency distribution of the liquid layer 180 can be enlarged, when heat energy is transferred between the low frequency vibrator 110 and the liquid layer 180. Can be suppressed. Therefore, heat energy can be more efficiently transferred between the solid layer 170 and the liquid layer 180 via the high-frequency vibrator 100 and the low-frequency vibrator 110 than in the first embodiment. That is, according to the present embodiment, the heat exchange performance of the heat exchanger can be further improved than in the first embodiment.

(Other embodiments)
In the above embodiment, the inner peripheral surface of the flat tube 10 that becomes the solid-liquid interface has been described as an example. The vibrator formed at the solid-gas interface is set so that the vibration frequency peak is higher than the vibration frequency peak of the gas layer molecules and lower than the vibration frequency peak of the surface atoms of the solid layer.

The vibration frequency of molecules in the gas layer is several GHz (on the order of 10 ⁹ Hz), similar to the vibration frequency of molecules in the liquid layer. For example, assuming that the gas is a monoatomic molecule ideal gas, the thermal oscillation frequency of the gas molecule is defined as the average velocity V of the gas molecule divided by the average free path L (thermal oscillation frequency = average velocity V / mean free). Process L). Average velocity V is determined using atomic mass Ma, Boltzmann constant kB (= 1.38 × 10 ⁻²³ J / K) and temperature T,
V = √ ((3 kB × T) / Ma)
It is expressed. When the atomic mass Ma is 4.65 × 10 ⁻²³ (= 28 / (6.02 × 10 ²³ )) g and the temperature T is 300 K, the average speed V is about 516 m / s.

On the other hand, the mean free path L is obtained by using the gas volume V0, the Avogadro number Nb (= 6.02 × 10 ²³ ), and the diameter σ of the gas molecule,
L = V0 / (√2 × π × Nb × σ ² )
It is expressed. If the gas volume V0 is 22.4 l and the diameter σ is 3 nm, the mean free path L is about 93 nm. Therefore, the thermal oscillation frequency of the monoatomic molecule ideal gas is about 5.5 GHz (= 516 (m / s) / (93 × 10 ⁻⁹ (m))).

  In the above embodiment, alumina nanoparticles are taken as an example of the material of the vibrators 92, 102, and 112, but other materials may be used.

  Furthermore, in the above-described embodiment, the shapes of the vibrators 92, 102, and 112 are substantially cubic, but may be other shapes such as a sphere or a shape based on the molecular structure of the constituent molecules.

  Moreover, in the said embodiment, although the carbon nanotube was mentioned as an example as a material of the elastic support part 91, you may form with another material.

  Further, in the second embodiment, two types of vibrators (high frequency vibrator 100 and low frequency vibrator 110) having different vibration frequencies are used, but three or more kinds of vibrators having different vibration frequencies may be used. Good.

  Moreover, in the said embodiment, although the radiator 1 was mentioned as an example as a heat exchanger, it is applicable also to another heat exchanger.

1 Radiator (heat exchanger)
10 Flat tube 70, 170 Solid layer 75, 175 Solid-liquid interface 80, 180 Liquid layer (fluid layer)
90 Vibrators 91, 101, 111 Elastic support portions 92, 102, 112 Vibrating body 100 High frequency vibrator (first vibrator)
110 Low frequency oscillator (second oscillator)

Claims (2)

A solid layer (70) that exchanges heat with the fluid layer (80) at an interface (75) with the fluid layer (80);
A vibrating body (92) provided at the interface (75) and capable of propagating thermal vibrations between surface atoms of the solid layer (70) and molecules of the fluid layer (80); An oscillator (90) provided with an elastic support portion (91) for elastically supporting (92) with respect to the solid layer (70),
The vibration frequency peak (Wv) of the vibrator (90) is higher than the molecular vibration frequency peak (Wl) of the fluid layer (80), and the vibration frequency peak of surface atoms of the solid layer (70). Configured lower than (Ws),
The vibrator (90) includes a first vibrator (100) and a second vibrator (110),
The first vibrator (100) propagates thermal vibrations between surface atoms of the solid layer (170) and molecules of the fluid layer (180) through the second vibrator (110). Thermal vibration is propagated between
In the second vibrator (110), thermal vibration is propagated between molecules of the fluid layer (180), and surface atoms of the solid layer (170) are passed through the first vibrator (100). Thermal vibration is propagated between
The vibration frequency of the peak of the first oscillator (100) (wv 2), the heat transfer member you being higher than the peak (WV1) of the oscillation frequency of the second oscillator (110). A heat exchanger comprising the heat transfer member according to claim 1 .

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