CN1685193A

CN1685193A - Heat transfer method and heat exchange system between solid and fluid

Info

Publication number: CN1685193A
Application number: CNA028297377A
Authority: CN
Inventors: 功刀资彰; 向胜己
Original assignee: ISEYA MANUFACTURING Co
Current assignee: ISEYA MANUFACTURING Co
Priority date: 2002-10-10
Filing date: 2002-12-25
Publication date: 2005-10-19
Also published as: KR20050053743A; JP3690527B2; AU2002360005A1; WO2004033980A1; JPWO2004033980A1

Abstract

In a method for conducting heat between a solid such as metal and a fluid such as water and air, the solid surface in contact with the fluid is treated by a paste consisting of particles of copper oxide CuO, carbon C, or alumina Al2O3 having a diameter of 100 nm or below and acid or alkali, thereby forming a porous layer on the solid surface having a plenty of nano-size pores. This provides a bland new method exhibiting a significantly high efficiency at low cost for the convective heat transfer in the heat conduction phenomenon.

Description

Heat-transferring method between solid and the fluid and heat-exchange system thereof

Technical field

The present invention relates to heat-transferring method and heat-exchange system thereof between solid and the fluid.

Background technology

The transmission of heat energy roughly can be divided into three kinds of transport phenomenas, i.e. heat radiation, heat conduction and convection heat transfer' heat-transfer by convection.In commercial Application, the transmission of heat energy becomes very big theme, not only is used for conserve energy, and is used for utilizing sensible heat and latent heat transmission or power conversion and transferring heat to other media by any media in current global environment scope improving the thermal efficiency.

An object of the present invention is to provide a kind of new method, this method has extra high efficient and low cost with respect to the convection heat transfer' heat-transfer by convection in the heat transfer phenomenon (convection heat transfer' heat-transfer by convection).Another object of the present invention provides the heat-exchange system based on this new method.

Summary of the invention

To achieve these goals, the present invention relates to the heat-transferring method between solid (for example metal) and fluid (for example water and air), it is characterized in that: with the surface of solids that one group of particle disposal contacts with fluid, the diameter of this particle is equal to or less than 100nm (hereinafter referred to as " nano particle ").

Usually, propose and sum up the heat transfer phenomenon with the experience correlation formula, wherein, the dynamic characteristic of Re (Reynolds number) expression fluid motion, the thermal characteristics of Pr (Prandtl number) expression working fluid, heat transfer between Nu (Nusselt number) the expression working fluid and the surface of solids, Gr (Grashof number) expression when working fluid be the buoyancy-driven that causes owing to temperature or the density contrast hot fluid characteristic when mobile.These correlation formulas are used for estimating the heat transfer efficiency of suitable heat condition.

But many these experience correlation formulas based on dimensionless number are to derive by temperature and VELOCITY DISTRIBUTION based on the fluid of boundary layer theory.According to the present invention, handle the surface of solids of contacting with fluid with the nano particle group, form the porous layer in hole thus from the teeth outwards with a plurality of nanoscales.Therefore, the heat-transfer mechanism in the laminar flow viscous sublayer obtains very big improving (in traditional theory, only conduct as the molecular heat in fluid and handle this bottom), has finally improved heat transfer efficiency.

In convection heat transfer' heat-transfer by convection, when high temperature heat source during in the solid side, method of the present invention can be used to make heat to pass to cryogen from high-temp solid, and on the contrary, when high temperature heat source during in fluid side, method of the present invention also can make heat pass to low-temperature solid from high temperature fluid.

Therefore realize that suitable heat-exchange system of the present invention is characterised in that the surface of solids contacts with fluid.On the surface of solids of heat-exchange system, form and comprise the porous layer that a plurality of diameters are equal to or less than the hole of 100nm.

The aforementioned particles group can be cupric oxide (CuO), carbon (C), aluminium oxide (Al ₂O ₃) or the like.Particle has sphere usually; But grain shape is not limited in this, and for example, this particle can have the tubular of single or multiple lift when for carbon, and diameter can be less than about 100nm when being CNT.

Description of drawings

Fig. 1 represents to be used for to determine the schematic diagram of the experimental provision of effect of the present invention.Fig. 2 represents the result of example 1, wherein uses aforementioned means to measure temperature.Fig. 3 represents from the relative evaluation of the heat transfer coefficient of Fig. 2 calculating.Fig. 4 represents the result of example 2, wherein uses aforementioned means to measure temperature.Fig. 5 represents from the relative evaluation of the heat transfer coefficient of Fig. 4 calculating.Fig. 6 represents the result of comparative example, wherein uses aforementioned means (removing heat transfer plate from this device) to measure temperature.Fig. 7 represents to be used for to determine the schematic diagram of another experimental provision of effect of the present invention.Fig. 8 represents the experimental result 1 of example 3, wherein uses aforementioned means to measure temperature.Fig. 9 represents the water temperature rate of change of experimental result 1.Figure 10 represents the experimental result 2 of example 3, wherein uses aforementioned means to measure temperature.Figure 11 represents the water temperature rate of change of experimental result 2.Figure 12 represents the plane of another experimental provision of definite effect of the present invention.Figure 13 represents the front view of same device.

The specific embodiment

Example 1

[experimental provision]

Fig. 1 represents to be used for to determine the schematic diagram by the experimental provision of the effect of method generation of the present invention.This experimental provision mainly comprises cylindricality cavity 1, cooling chamber 2, temperature controller 3, temperature monitoring 4, the circulating pump 5 that is used for working fluid, the circulating pump 6 that is used for cooling water and cooling water tank 7, and is placed in 25 ℃ the room.

Cylindricality cavity 1 comprises: by the cylinder 8 that hard vinyl chloride is made, its internal diameter is 100mm, highly is 100mm; By the cover plate 9 that SUS304 makes, it is fixed on the upper end face in fluid-encapsulated mode; And the base plate of making by SUS304 10, it is fixed on the rear surface in fluid-encapsulated mode.Cover plate 9 and base plate 10 are dish types, and its thickness is 10mm.Dish type heat transfer plate 11 is made of copper and external diameter is that 99.5mm and thickness are 1.5mm, and this heat transfer plate 11 for example passes through the lower surface that screw shown in silicone grease (by Taiwan Plowstar Co., the model AK-100 that Ltd. makes) the (not shown) usefulness is fixed on cover plate 9.And the external diameter of baffle heater 12 is 100mm, and thermal capacity is 80W, and this baffle heater 12 is installed in the upper surface of cover plate 9 through silicone grease (the same).The thickness of each silicone grease is 0.05mm approximately, and 11 distance is heat conduction area (the heat transmission in solid) from baffle heater 12 to heat transfer plate.Cover plate 9, heat transfer plate 11 and baffle heater 12 all have the through hole that diameter is 10mm at the center, pipe 13 inserts in fluid-encapsulated mode, are used to ventilate and the volumetric expansion amount when the working fluid volumetric expansion, pressure discharge.The upper surface of the outer peripheral face of cylinder 8 and baffle heater 12 (except the center) is covered by heat-insulating material 25.

Two inside that the temperature sensor of being made by RTD 14,15 inserts cover plate 9, one of them temperature sensor 14 is connected with temperature controller 3, so that carrying out the PI of cover plate 9 controls automatically to reach temperature required, another temperature sensor 15 is connected with temperature monitoring 4, and this temperature monitoring 4 is used for monitoring cover plate 9 temperature inside.At this, the temperature sensor 16 of the about 0.9mm of thickness that is made by the RTD film is installed in the border between cover plate 9 and the heat transfer plate 11, and this temperature sensor 16 is connected with temperature monitoring 4, is used for monitoring the upper surface temperature of heat transfer plate 11.Simultaneously, five temperature sensors 17 to 21 vertically insert in the cylinder 8 so that equal intervals is whole; Another temperature sensor 12 is imbedded the inside of base plate 10; And in the water of another temperature sensor 23 immersion cooling water tanks 7, all these sensors all are connected with temperature monitoring 4.

On the other hand, cooling chamber 2 be arranged in cylindricality cavity 1 below support this cylindricality cavity 1, the pedestal of being made by SUS304 24 that is positioned at cooling chamber 2 upsides closely contacts with base plate 10.The internal diameter of cooling chamber 2 is 100mm, and free in the institute of experimentation, and it is 27.7 ℃ cooling water that the inside of cooling chamber is full of the temperature of supplying with from cooling water tank 7, and this cooling water circulates by cooling water circulating pump 6.In addition, cylindricality cavity 1 is in the state that is full of running water, and the running water that wherein circulates is so that spray running water by the circulating pump 5 that is used for working fluid from the top suction with from the bottom.

In above-mentioned experimental provision, control baffle heater 12 is used for the adjustment to 50 of cover plate 9 ℃ is determined that thus the temperature of each several part after 40 minutes is in stable state.

Then, cupric oxide CuO particle is (by U.S. Nanophase Technologies Co., Ltd. make, by based on the determined average particle size particle size of measurement=16 of the SSA (specific surface area) of BET method to 32nm, almost spherical) and nitric acid mix and be prepared into pasty state, be applied on the whole lower surface of heat transfer plate 11 drying, water flushing then then.Generally acknowledge that the thin layer that produces from the nano particle of cupric oxide forms at lower surface, pastel is applied on this lower surface.When with SEM (after this referring to SEM) when observing this layer, this layer has the hole that a plurality of diameters are equal to or less than 100nm.

[experimentation and result]

Add heat transfer plate 11 again in above-mentioned experimental provision, the porous layer that produces from copper oxide nanometer particle forms at this heat transfer plate 11; Open baffle heater 12 so that the temperature of cover plate 9 is 50 ℃ or 45 ℃; The temperature of each several part was measured once every one minute after startup; And experiment finishes when having spent 20 minutes again after the stable state (the wherein temperature constant of each several part).At this, for relatively, and measure temperature under the same terms before forming porous layer on the heat transfer plate 11.Measurement result as shown in Figure 2.Each temperature on the diagrammatic sketch is the mean value of 20 times measured value, the position of trunnion axis representation temperature sensor, and the distance of base plate 10 is left in the numerical value representative on trunnion axis.In the drawings, [copper coin+CuO particle 01] expression is when adopting heat transfer plate 11 (porous layer that produces from copper oxide nanometer particle forms at heat transfer plate 11), data when the specified temp of cover plate 9 is made as 50 ℃, and [copper coin+CuO particle 02] expression is when the data that obtain when confirming the repeatability duplicate measurements under the same conditions.And, the data of [copper coin+CuO particle 03] expression when specified temp is made as 45 ℃.And [only copper coin 01], [only copper coin 02] and [only copper coin 03] expression are by measure resulting data under aforesaid the same terms, except only having used the mixture of nitric acid rather than copper oxide nanometer particle and nitric acid.

At first, because the data of [only copper coin 01] and [only copper coin 02] are almost overlapped, so think that method of the present invention has repeatability.Note to determine from heat transfer plate to being positioned at [80mm] heat transfer to the water of [20mm] according to significant difference owing to the water temperature that has or do not have nano particle to cause.On the other hand, can suppose that the heat transfer from the water of the lower floor [20mm] that is arranged in the cylindricality cavity to base plate is identical condition in whole experiment (comprising cooling water), so base plate has the temperature corresponding to water temperature naturally.

[heat transfer efficiency]

Above-mentioned data are states when stablizing based on the temperature of each several part.And, from these data, be appreciated that, fluid temperature (F.T.) in the cylindricality cavity is represented the mean temperature of the underlaying surface temperature of the upper surface temperature of cover plate 9 and base plate 10, therefore expression does not have heat loss from the cylindricality cavity, because the fluid mass in the central region of cylindricality cavity is an isothermal, has formed adiabatic zone in the fluid mass.Therefore, the hot-fluid of the upper surface of process cylindricality cavity (diameter 100mm) has experienced the convection heat transfer' heat-transfer by convection with the fluid mass, middle part in the upper flow zone of cylindricality cavity, do not have the heat waste lost territory by the transmission of fluid mass, middle part, experienced convection heat transfer' heat-transfer by convection in the lower flow zone with base plate.At this moment, we can say that the magnitude through the hot-fluid of fluid mass, upper and lower is the same.By this experiment, can know to have a kind of heat transfer mechanism.

The temperature of supposing temperature, the water temperature in the cylindricality cavity and the base plate of heat transfer plate is respectively TC, TwM and TB, is that the heat transfer plate of S is q to the heat flow and the heat transfer coefficient of water from area _UpperAnd α _CuTop, heat flow from the bottom aqua region to base plate and heat transfer coefficient are q _LowerAnd α _Bottom, following formula is set up and is used for respectively organizing parameter:

q _upper*S＝α _CuTop*(TC-TwM)*S

q _lower*S＝α _bottom*(TwM-TB)*S

Because hot-fluid is identical: q under aforesaid stable state _Upper* S=q _Lower* S, following formula is set up:

α _CuTop/α _bottom＝(TwM-TB)/(TC-TwM)

Fig. 3 represents the α based on each experimental example of Fig. 2 _CuTop/ α _BottomValue.Under the rotation number of pump 5 was constant condition, flox condition can be thought identical, therefore the heat transfer coefficient α from the bottom aqua region to base plate _BottomCan think constant.So α _CuTop/ α _BottomValue in fact can think and represented α _CuTopFeature, promptly from the relative growth rate of the heat transfer coefficient of the heat transfer plate in upper water zone.

Be not all 50 ℃ and 45 ℃, α even be appreciated that the specified temp of lid from Fig. 3 _CuTop/ α _BottomValue do not have difference.We can say that this point is in conjunction with thinking that data have the repeatable fact, proved correctness the supposition of the above-mentioned evaluation of heat transfer coefficient.

Be enough to surprisingly, because form the porous layer that is produced by small amounts copper CuO nano particle on heat transfer plate (copper coin) surface, the heat transfer coefficient from copper to water has relatively increased by 60% or more with the characteristic of independent heat transfer plate.Therefore, from heat transfer notion, have to think that porous layer itself has a significant impact the temperature boundary layer tool based on the fluid boundary shelf theory.And, infer that this influence does not rely on to a great extent as the metal of parent or the chemical species of employed nano particle.

Example 2

With [copper coin+CuO particle 01] of example 1 in the same terms under measure temperature, except replacing copper oxide nanometer particle to handle heat transfer plate 11 with CNT (diameter 20 to 30nm, length 5 to 10 μ m).Temperature measurement result is shown in [copper coin+C pipe 01] among Fig. 4.At this, when observing heat transfer plate 11 surperficial with SEM, find to have formed the have a plurality of holes layer of (diameter 100nm).Simultaneously, find to keep the small amount of carbon nanotubes of original-shape to stick on this surface.

With [copper coin+CuO particle 01] of example 1 in the same terms under measure temperature, except using aluminium oxide AL ₂O ₃Particle (by U.S. Nanophase Technologies Co., Ltd. makes, and average particle size particle size is 27 to 56nm, and is roughly spherical) replaces the copper oxide nanometer particle layer to handle heat transfer plate 11.[copper coin+AL among temperature measurement result such as Fig. 4 ₂O ₃Particle 01] shown in.At this, when observing heat transfer plate 11 surperficial with SEM, find to have formed layer with a plurality of holes (diameter is equal to or less than 100nm).

With [copper coin+CuO particle 01] of example 1 or the same terms in [only copper coin 01] under measure temperature, except the material of heat transfer plate 11 becomes brass from copper.Temperature measurement result among Fig. 4 respectively shown in [brass sheet+CuO particle 01] or [only brass sheet 01].

With [copper coin+CuO particle 01] of example 1 or the same terms in [only copper coin 01] under measure temperature, except the material of heat transfer plate 11 becomes aluminium from copper, and handle aluminium oxide AL with caustic soda ₂O ₃Particle.Temperature measurement result in Fig. 4 respectively as [aluminium sheet+AL ₂O ₃Particle 01] or [only aluminium sheet 01] shown in.

At this, [only copper coin 01] and [only copper coin 02] is the duplicating of data (for relatively) among Fig. 3.

Can clearly be seen that from figure the difference (because the porous layer that has or do not produce from nano particle) that can determine to test water temperature has nothing to do with the material of heat transfer plate and the chemical composition of employed nano particle.The result of copper heat transfer plate and CNT [copper coin+C pipe] shows relative low water temperature, and its reason seems to be: compare with other nano particle, CNT forms the possibility of porous layer on heat transfer plate less.Under any circumstance, can determine the repeatability of honeycomb sandwich, following phenomenon not occur: for example for each repeated experiments, the structure degree reduces or the heat transfer coefficient variation.

Next, Fig. 5 represented when adopt with example 1 in the identical computing formula result when calculating heat transfer coefficient.With regard to these DSs, the result who obtains is that the value that the combination of brass heat transfer plate and copper oxide nanometer particle [brass sheet+CuO particle] obtains is the highest, that is, heat transfer coefficient is best.Compare with independent heat transfer plate, this value shows surprising improvement the (80% or more).

Comparative example

From the experimental provision of example 1, remove heat transfer plate 11 and temperature sensor 16.Then, the concentration with 0.01g/L adds aforesaid CNT in the water of cylindricality cavity 1.Promptly made following structure: the water that contains CNT contacts with the lower surface of cover plate 9.With other the same terms of [copper coin+CuO particle 01] of example 1 under measure temperature.And, as control, in water, do not add under the situation of CNT and measure temperature.These temperature measurement result are respectively as [adding the C pipe] and [not having] order expression in Fig. 6.

The water temperature that is appreciated that [not having] from Fig. 6 is higher approximately 0.6 ℃ than the water temperature of [adding C manages].By the way, CNT does not dissolve in water, and when finishing experiment, the phenomenon of seeing is that aggregation of particles forms group.

With regard to α _CuTop/ α _BottomValue, α under the situation of the water that contains CNT _CuTop/ α _Bottom=0.3576 value is than only being α under the situation of water _CuTop/ α _Bottom=0.3667 value is slightly little.Therefore, think owing to add a bit decline of CNT heat transfer coefficient.

Example 3

[experimental provision]

As shown in Figure 7, be equipped with boiler 28 and cold water storage cistern 29.And the flow channel of being made up of two (upper and lower)

conduits

31 and 32 forms and has cuboid box 30, and this cuboid box 30 is made by hard vinyl chloride resin, and thickness is 10mm.

Flow channel

31 and 32 has the cross section of unified size, and its streamwise height is 15mm, and width is 310mm, and upper flow passage 31 and lower flow passage 32 are that the copper coin 33 of 1.5mm is separated by thickness.Passage 31 and 32 has at the inlet of an end of flow direction with in the outlet of the other end.

Tilt this case 30 so that inlet exports upwards downwards.Give the inlet hot-water supply of upper flow 31 respectively by

pump

34 and 35, give the inlet supply cold water (cold be running water) of bottom flow channel 32.Then, hot water and the cold water that flows out from the outlet of

flow channel

31 and 32 flows into hot-water cylinder 28 and cold water tank 29 respectively downwards.Adopt a unshowned valve to regulate, make flow velocity

identical.Temperature sensor

36,37,38 and 39 distances with L=1.8m are arranged in upstream (near inlet) and downstream (near the outlet) of

flow channel

31 and 32, so that measure water temperature automatically.After the inlet temperature of hot water and cold water reaches stable state, to measure again 10 minutes every 10 seconds, (number of data: each mean value 30) is considered to measurement result to the measured value from these measured values during at least 5 minutes (or more).

Heat is transferred to the cold water in lower flow zone from the hot water in upper flow zone through copper coin 33.Thereby the hot water temperature of the 1.8m that flowed reduces, and cold water temperature raises on the contrary.Each temperature difference is determined by following factors: because the heat conduction of the physical characteristic of copper coin 33 (this copper coin is separated the fluid of two upper and lower layers) self, 33 heat transfer from hot water to the copper coin, and heat transfer from copper coin 33 to cold water.Naturally, heat transfer coefficient is high more, and the temperature difference is big more.

This experiment is carried out under following four kinds of conditions: the situation [only copper coin] of only using nitric acid treatment copper coin 33, as handle the situation [two sides use nano particle] on two surfaces of copper coin 33 in the example 1 with the same pastel that comprises copper oxide nanometer particle, handle a situation [hot surface use nano particle] of copper coin 33 on the surface of hot water side with the pastel that comprises copper oxide nanometer particle, and opposite, use the pastel that comprises copper oxide nanometer particle to handle a situation [cold surface use nano particle] of copper coin 33 on the surface of cold water side.

[experimental result 1]

Experimental result under the situation of flow velocity u=4.41cm/sec as shown in Figure 8.For all four kinds of conditions, the inlet temperature (H of hot water _Inlet) and the inlet temperature (C of cold water _Inlet) almost under identical condition.

By comparing [two sides use nano particle] and [only copper coin], the temperature difference of the entrance and exit of hot water and cold water has tangible difference.(0.31m * 1.8m) is identical, can think that this difference is owing to producing with the different of heat transfer coefficient from the copper coin to cold water from hot water to the copper coin because the flow velocity of two flow channels and heat transfer area.

The result of [only copper coin] can be from experience correlation formula (the Churchill ﹠amp of pipe laminar commonly used; The Ozoe formula) infer, calculated value is gone up consistent with experiment value in sizable precision (calculated value of outlet temperature is 0.36 ℃ with the difference of experiment value).As a comparison, the experiment value of [two sides use nano particle] shows improvement, because the heat transfer coefficient from hot water to copper and from copper to cold water respectively is 1.8 times of calculated value.

The result of [hot surface use nano particle] and [cold surface use nano particle] is illustrated respectively in formation and has improved heat transfer coefficient under the situation of the porous layer of nano particle generation.

Fig. 9 represents The above results with the bar chart water temperature rate of change of heat exchange (under the situation of U=4.4cm/s by).Based on the inlet temperature difference (Inlet) of hot water and cold water, the hot water temperature difference (Hot=H _Inlet-H _Outlet) and the cold water temperature difference (Cool=C _Outlet-C _Inlet) ratio be expressed as (Hot/Inlet) and (Cool/Inlet).The value of [1-(Outlet)/(Inlet)] is the outlet temperature poor (Outlet) that has wherein added hot water and cold water, (Hot/Inlet) with value (Cool/Inlet) and that also represented [1-(Outlet)/(Inlet)].From conceptive, the magnitude of the value of [1-(Outlet)/(Inlet)] has been represented the improvement degree of heat exchange (promptly conducting heat), (Hot/Inlet) with the percentage contribution of (Cool/Inlet) representing separately.

Under the situation of [two sides use nano particle] and [only copper coin], be identical degree (Hot/Inlet) with the value of (Cool/Inlet), this is illustrated in, and heat exchange is fixing the establishment under the situation of common concurrent flow.Therefore, it seems the theory that can use heat exchange, it is effective can determining to calculate by the estimation of aforementioned experience correlation formula.

[experimental result 2]

Experimental result under the situation of the about 8cm/sec of flow velocity u=as shown in figure 10.Because flow velocity is fast, be difficult to the inlet temperature (H of the hot water of four kinds of conditions of control _Inlet) and the inlet temperature (C of cold water _Inlet), therefore used some different conditions.

Figure 11 comes with bar chart (by the water temperature rate of change of heat exchange, the about 8cm/sec of u=) ecbatic in the mode identical with experimental result 1.The experimental result under each condition express with before the identical trend of result of situation (flow velocity is U=4.41cm/s).Experimental result and under the situation of [only copper coin] by formula (by turbulent flow being added the formula that above-mentioned experience correlation formula obtains (the turbulent Petukhov updating formula in the pipe and the Churchill ﹠amp of laminar flow; The Ozoe formula)) result of calculation that obtains is in excellent precision (difference of outlet temperature is 0.02 ℃) unanimity.As a comparison, the experiment value of [two sides use nano particle] shows improvement, because the heat transfer coefficient from hot water to copper and from copper to cold water respectively is 2.1 times of calculated value.

Figure 11 has also simply represented four kinds of experiment conditions.This is because of [one side the is used nano particle] centre at [only copper coin] and [two sides use nano particle].

[about the loss of flowing] along with fluid

When estimating common general heat-exchange system, think that in many cases fin etc. is to be used for for example increasing heat transfer area.But they have negative element together, because energy loses along with the mobile increase of fluid.Therefore, since the passage friction loss that causes of porous layer be increased in the overall evaluation system time be indispensable.

In this experiment, measure friction loss.But pass through based on experience correlation formula commonly used (the general resistance law of plain tube: the calculating approximate formula of the Colebrook of PrandtlKarmann formula and the equivalent sand roughness of consideration), the loss that only produces about 0.9mm water column for 1.5m flow channel at interval, in fact, can only estimate the loss that is less than or equal to the 1.0mm water column with pressure gauge.About owing to have or do not have the estimation of the friction loss of porous layer, the experiment that must improve flow velocity.But following result well as if coat with lacquer is noted having obtained in the surface that forms porous layer thereon: by the calculating according to the Moody figure that introduces equivalent sand roughness, even compare with plain tube, also only cause coefficient of friction increase by 3% or still less.

Example 4

Example before this example all is that fluid is the situation of water.In this example, fluid is an air.Ends of the test board 40 that obtains by the step identical with [only copper coin] with [copper coin+CuO particle 01] of example 1 fixing obliquely (inclined angle alpha=30 degree) 41 outlets in the air channel are shown in the front view of the vertical view of Figure 12 and Figure 13.And the temperature sensor of being made by the RTD film 42 is installed in the back side of test board 40, and temperature sensor 43 is installed near the outlet in air channels 41.Then, hot blast (117 ℃) blows on the test board 40 with the air velocity of 0.5m/s, determines that hot blast is not around the dorsal part to test board 40.Measure the temperature of the test board 40 that reaches stable state with temperature sensor 42.The result recognizes clearly difference, and the temperature of [only copper coin] is that 57.5 ℃ of temperature with [copper coin+CuO particle 01] are 59.2 ℃.

Industrial usability

As mentioned above, according to the present invention, simple by handle the surface of solids that contacts with fluid (as heat transfer object) with nano particle, the layer that perhaps has the hole of a plurality of nano-scales by formation, heat transfer coefficient significantly improves, therefore the present invention is useful in heat-exchange system, and this heat-exchange system for example air-conditioning or hot water supplier maybe needs the every field of conducting heat.

Claims

1. heat-transferring method between solid and fluid is characterized in that: the surface of solids that contacts with fluid with one group of particle disposal with 100nm or littler diameter.

2. method according to claim 1 is characterized in that: when handling, described groups of grains is mixed with acid or alkali.

3. method according to claim 1 and 2 is characterized in that: described solid is a metal.

4. according to the described method of one of claim 1 to 3, it is characterized in that: described groups of grains is from cupric oxide CuO, carbon C and aluminium oxide Al at least ₂O ₃In select one.

5. method according to claim 1 and 2 is characterized in that: described solid is a metal, and described groups of grains is to be made by the oxide of the metal identical with solid or this metal.

6. according to the described method of one of claim 1 to 5, it is characterized in that: described fluid is water or air.

7. system that carries out heat exchange between solid and fluid, it is characterized in that: this system is provided with the solid with the surface that contacts with fluid, wherein, forms the porous layer in the hole that comprises a plurality of 100nm of having or littler diameter on described surface.

8. system according to claim 7, it is characterized in that: described solid has second surface and spacer body, described second surface contacts with second fluid, described second fluid has the temperature different with described first fluid, and described spacer body makes described first fluid and described second fluid not to mix.

9. according to claim 7 or 8 described heat-exchange systems, it is characterized in that: described porous layer is produced by one group of particle, and described particle has 100nm or littler diameter.

10. according to the described heat-exchange system of one of claim 7 to 9, it is characterized in that: described solid is a metal.

11. according to claim 9 or 10 described heat-exchange systems, it is characterized in that: described groups of grains is from cupric oxide CuO, carbon C and aluminium oxide Al at least ₂O ₃In select one.

12. heat-exchange system according to claim 9 is characterized in that: described solid is a metal, and described groups of grains is to be made by the oxide of the metal identical with solid or this metal.

13. according to the described heat-exchange system of one of claim 7 to 12, it is characterized in that: described fluid is water or air.