A method, device, equipment and medium for analyzing heat transfer characteristics of nanofluid

Abstract

The present application relates to the technical field of fluid heat dissipation, in particular to a method, device, equipment and medium for analyzing heat transfer characteristics of nanofluid. The present application constructs a velocity calculation formula based on a power-law fluid model, then applies the velocity calculation formula to the slip length, fluid attribute information and pipeline attribute information to obtain the flow velocity of the nanofluid in the micro pipeline, then calculates the average temperature of the nanofluid in the micro pipeline based on the flow velocity, and finally calculates the Nusselt number of the nanofluid in the micro pipeline based on the average temperature. Since the power-law fluid model can describe the non-Newtonian characteristics of the nanofluid, and the non-Newtonian characteristics are suitable for the heat transfer characteristics of the nanofluid in the micro pipeline, the flow velocity, average temperature and Nusselt number of the present application can describe the heat transfer characteristics of the nanofluid in the micro pipeline, so that the present application can apply the nanofluid to microscale cooling.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluid heat dissipation technology, in particular to a method and device for analyzing heat transfer characteristics of nanofluid, equipment and medium. BACKGROUND

[0002] The nanoscale metal particles (the diameter of the metal particles is 1-100 nm) doped in the liquid form a mixed liquid, which is the nanofluid. The nanoscale metal particles have a large relative surface area, which helps to strengthen heat transfer, and can be suspended in the liquid for a long time and is not easy to precipitate because the geometric size is closer to the liquid molecules. The nanometer particles commonly used to prepare nanofluids are divided into two categories: (1) metal particles such as Cu, Al, Fe, Au, and Ag; and (2) metal oxide particles such as Al203, CuO, Fe304, TiO2, and SiC. Common base liquids (i.e., the above-mentioned liquid) include water, oil, acetone, and decene.

[0003] Existing research applies nanofluids to the cooling of integrated circuits and electronic mechanical systems at a macro scale. In most existing research, nanofluids are regarded as single-phase fluids and it is assumed that the nanometer particles are uniformly distributed in the base liquid. The most effective research method for single-phase nanofluids is to apply the research results on the flow and heat transfer of fluids at a macro scale. However, the research results for macro-scale problems cannot be directly applied to micro-scale problems because, as the scale decreases, the no-slip boundary condition at a macro scale cannot be applied to a micro scale.

[0004] In summary, the existing technology cannot apply nanofluids to cooling at a micro scale.

[0005] Therefore, the existing technology needs to be improved and enhanced. SUMMARY

[0006] To solve the above technical problems, the present application provides a method and device for analyzing heat transfer characteristics of nanofluids, equipment and medium, which solves the problem that the existing technology cannot apply nanofluids to cooling at a micro scale.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a method for analyzing heat transfer characteristics of nanofluids, the heat transfer characteristics including the flow velocity and average temperature of the nanofluid in a pipe and the Nusselt number, wherein the method comprises:

[0009] acquire a slip length between a micro-pipe and the nanofluid, acquire fluid attribute information of the nanofluid, and acquire pipe attribute information of the micro-pipe, and apply a velocity calculation formula constructed based on a power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain a flow velocity of the nanofluid in the micro-pipe;

[0010] determine an average temperature of the nanofluid in the micro-pipe based on the flow velocity;

[0011] determine a Nusselt number of the nanofluid in the micro-pipe based on the average temperature.

[0012] In an implementation, applying the velocity calculation formula constructed based on the power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain the flow velocity of the nanofluid in the micro-pipe includes:

[0013] determining a flow index and a fluid consistency in the fluid attribute information;

[0014] determining a critical strain rate and a wall strain rate and size data in the pipe attribute information;

[0015] applying the velocity calculation formula constructed based on the power-law fluid model to the slip length, the flow index, the fluid consistency, the critical strain rate, the wall strain rate, and the size data to obtain the flow velocity of the nanofluid in the micro-pipe.

[0016] In an implementation, determining the average temperature of the nanofluid in the micro-pipe based on the flow velocity includes:

[0017] acquiring a temperature distribution function of the nanofluid along a radial direction of the micro-pipe, and acquiring a radius size of the micro-pipe;

[0018] multiplying the temperature distribution function by the flow velocity and then by a radius parameter to obtain a first integral term, and calculating a first integral value of the first integral term in an interval of zero to the radius size;

[0019] multiplying the flow velocity by a radius parameter to obtain a second integral term, and calculating a second integral value of the second integral term in the interval of zero to the radius size;

[0020] determining the average temperature of the nanofluid in the micro-pipe according to the first integral value and the second integral value.

[0021] In an implementation, determining the Nusselt number of the nanofluid in the micro-pipe based on the average temperature includes:

[0022] obtaining a temperature distribution function of the nanofluid along a radial direction of the micro-pipe, and obtaining a radius size of the micro-pipe;

[0023] performing a differential calculation on the temperature distribution function with respect to a radius parameter to obtain a differential expression, and applying the differential expression to the radius size to obtain a differential value;

[0024] determining a wall temperature of the nanofluid at an inner wall surface of the micro-pipe;

[0025] obtaining a Nusselt number of the nanofluid in the micro-pipe according to the average temperature, the wall temperature and the differential value.

[0026] In an implementation manner, the obtaining of the Nusselt number of the nanofluid in the micro-pipe according to the average temperature, the wall temperature and the differential value comprises:

[0027] subtracting the average temperature from the wall temperature to obtain a temperature difference value;

[0028] multiplying the differential value by a diameter of the micro-pipe to obtain a product value;

[0029] dividing the product value by the temperature difference value to obtain the Nusselt number of the nanofluid in the micro-pipe.

[0030] In an implementation manner, the velocity calculation formula is constructed in the following manner:

[0031] determining a rheological property of the nanofluid based on the power-law fluid model;

[0032] determining a slip boundary condition of the nanofluid;

[0033] constructing a velocity calculation formula according to the rheological property and the slip boundary condition.

[0034] In an implementation manner, the flow velocity, the average temperature and the Nusselt number are respectively subjected to dimensionless processing.

[0035] In a second aspect, an embodiment of the present application further provides a device for analyzing heat transfer characteristics of a nanofluid, wherein the device comprises the following components:

[0036] The flow velocity calculation module is configured to acquire a slip length between a micro-pipe and the nanofluid, acquire fluid attribute information of the nanofluid, acquire pipe attribute information of the micro-pipe, and apply a velocity calculation formula based on a power-law fluid model to the slip length, the fluid attribute information and the pipe attribute information to obtain a flow velocity of the nanofluid in the micro-pipe.

[0037] The average temperature calculation module is configured to determine an average temperature of the nanofluid in the micro-pipe based on the flow velocity.

[0038] The Nusselt number calculation module is configured to determine a Nusselt number of the nanofluid in the micro-pipe based on the average temperature.

[0039] In a third aspect, an embodiment of the present application further provides a terminal device, wherein the terminal device comprises a memory, a processor, and a nanofluid heat transfer characteristic analysis program stored in the memory and executable on the processor, and the processor implements steps of the nanofluid heat transfer characteristic analysis method when executing the nanofluid heat transfer characteristic analysis program.

[0040] In a fourth aspect, an embodiment of the present application further provides a computer readable storage medium, wherein the computer readable storage medium stores a nanofluid heat transfer characteristic analysis program, and steps of the nanofluid heat transfer characteristic analysis method are implemented when the processor executes the nanofluid heat transfer characteristic analysis program.

[0041] Beneficial effects: The velocity calculation formula is constructed based on the power-law fluid model, and then the velocity calculation formula is applied to the slip length, the fluid attribute information and the pipe attribute information to obtain the flow velocity of the nanofluid in the micro-pipe, and then the average temperature of the nanofluid in the micro-pipe is calculated based on the flow velocity, and finally the Nusselt number of the nanofluid in the micro-pipe is calculated based on the average temperature. The flow velocity, the average temperature and the Nusselt number of the nanofluid are the heat transfer characteristics of the nanofluid. Since the power-law fluid model can describe the non-Newtonian characteristics of the nanofluid, and the non-Newtonian characteristics are suitable for the heat transfer characteristics of the nanofluid in the micro-pipe, the flow velocity, the average temperature and the Nusselt number of the present application can describe the heat transfer characteristics of the nanofluid in the micro-pipe, so that the nanofluid can be applied to microscale cooling. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The overall flowchart of the present application is shown in FIG. 1;

[0043] Figure 2 The structure diagram of the nanofluid heat transfer characteristic analysis device provided by the present application is shown in FIG. 2;

[0044] Figure 3 An internal structure principle block diagram of a terminal device provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0045] The technical solutions in the present application are clearly and completely described below in combination with the embodiments and the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts are within the scope of the present application.

[0046] It is found through research that the mixing liquid is formed by doping metal particles of nanometer scale (the diameter of the metal particles is 1 to 100 nm) in a liquid, the mixing liquid is a nanofluid, the metal particles of nanometer scale have a large relative surface area, which helps to strengthen heat transfer, and can be suspended in the liquid for a long time and is not easy to precipitate because the geometric scale is closer to the liquid molecules. The nanoparticles commonly used to prepare the nanofluid are divided into two categories: (1) metal particles, such as Cu, Al, Fe, Au, and Ag; and (2) metal oxide particles, such as Al2O3, CuO, Fe3O4, TiO2, and SiC. Common base liquids (that is, the liquid mentioned above) include water, oil, acetone, decene, and the like.

[0047] The existing research applies the nanofluid to the cooling of integrated circuits and electronic mechanical systems of macro scale. In most of the existing research, the nanofluid is regarded as a single-phase fluid and it is assumed that the nanoparticles are uniformly distributed in the base liquid. The most effective research method for the single-phase nanofluid is to apply the research results about the flow and heat transfer of the fluid in the macro scale model. However, the research results for the macro scale problem cannot be directly applied to the micro scale problem, because with the decrease of the scale, the no-slip boundary condition of the macro scale cannot be applied to the micro scale.

[0048] To solve the above technical problem, the present application provides a nanofluid heat transfer characteristic analysis method, device, equipment and medium, which solves the problem that the existing technology cannot apply the nanofluid to micro scale cooling.

[0049] The nanofluid heat transfer characteristic analysis method of the embodiment can be applied to a terminal device. The terminal device can be a terminal product with data processing function, such as a controller of a cooling device. In the embodiment, as shown in Figure 1 The nanofluid heat transfer characteristic analysis method specifically includes the following steps:

[0050] S100, obtain a slip length between the micro-pipe and the nanofluid, obtain fluid attribute information of the nanofluid, and obtain pipe attribute information of the micro-pipe, and apply a velocity calculation formula constructed based on a power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain a flow velocity of the nanofluid in the micro-pipe.

[0051] The micro-pipe is a pipe of micrometer scale. The nanofluid heat transfer efficiency calculated using the power-law fluid model is obviously higher than the result calculated using the Newton fluid model.

[0052] S200, determine an average temperature of the nanofluid in the micro-pipe based on the flow velocity.

[0053] S300, determine a Nusselt number of the nanofluid in the micro-pipe based on the average temperature.

[0054] The steps S100, S200, and S300 of the embodiment can calculate the nanofluid heat transfer characteristics in the micro-integrated circuit and the micro-electro-mechanical system, that is, place the nanofluid in the micro-integrated circuit and the micro-electro-mechanical system, and cool the micro-integrated circuit and the micro-electro-mechanical system through the thermal conductivity of the metal particles in the nanofluid.

[0055] In the embodiment one, the step S100 of applying the velocity calculation formula constructed based on the power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain the flow velocity of the nanofluid in the micro-pipe includes the following specific steps S101, S102, and S103:

[0056] S101, determine a flow index n and a fluid consistency m in the fluid attribute information.

[0057] The values of the flow index n and the fluid consistency m are associated with the volume of the nanometer particles and the concentration of the nanometer particles. The volume of the nanometer particles is the volume of the metal particles of nanometer scale, and the concentration of the nanometer particles is the concentration of the metal particles of nanometer scale in the nanofluid.

[0058] S102, determine a critical strain rate γ c and a wall strain rate γ w and size data in the pipe attribute information.

[0059] The size data includes a radial coordinate r * of the micro-pipe and a radius a of the micro-pipe, and the critical strain rate γ c is a critical strain rate when the slip length bifurcates.

[0060] S103, regarding the slip length The flow index n, the fluid consistency m, and the critical strain rate γ c The wall strain rate γ w The size data is used to calculate the velocity u of the nanofluid in the microchannel using a velocity calculation formula based on a power-law fluid model. * .

[0061]

[0062] p * The pressure of the nanofluid, z * These are coordinates along the length of the microchannel (i.e., the axial direction of the microchannel). * indicates a dimensionless measurement, such as flow velocity u. * It refers to the dimensional flow velocity, flow velocity u. * The velocity of the nanofluid along the radial direction of the microchannel.

[0063] The velocity calculation formula in this embodiment is constructed as follows: based on the power-law fluid model, the rheological properties of the nanofluid are determined; the slip boundary conditions of the nanofluid are determined; and based on the rheological properties and the slip boundary conditions, the velocity calculation formula is constructed.

[0064] Based on the power-law fluid model, the rheological properties of the nanofluid are determined, and the rheological properties satisfy the following conditions:

[0065]

[0066] Slip boundary conditions:

[0067]

[0068] Combining rheological property conditions and slip boundary conditions in the radial direction r * Integrating over the given area will yield u. * The formula for calculating speed.

[0069] This embodiment also addresses the flow velocity u. * The dimensionless processing is performed to obtain the dimensionless flow velocity u. The specific process is as follows:

[0070] When in formula (1) When it is much less than 1, let r in formula (1) * Equal to zero, thus obtaining

[0071]

[0072] In the formula, k = n / (n+1), ρs respectively, k is a coefficient.

[0073] In the second embodiment, the step S200 of determining the average temperature of the nanofluid in the micro-pipe based on the flow velocity includes the following specific steps S201, S202, S203 and S204:

[0074] S201, obtaining a temperature distribution function T of the nanofluid along a radial direction r of the micro-pipe, * * and obtaining a radius size a of the micro-pipe.

[0075] T * = T·(T0-T w )+T w (2)

[0076] T w is a wall temperature, i.e., a temperature of the nanofluid at an inner wall of the micro-pipe, T0 is a temperature of the nanofluid at an inlet of the micro-pipe, and T w and T0 satisfy the following relationship:

[0077] T * (0,r * ) = T0, T * (z * ,a) = T w

[0078]

[0079] A i is a constant, λ i is an eigenvalue, and θ i (r) is a corresponding eigenfunction. A i and θ i (r) in the formula (3) are known, and λ i is calculated, T can be calculated through the formula (3), and the expression of T* can be obtained by substituting T into the formula (2), i.e., the formula (1)

[0080] λ i is solved by the following process:

[0081] |M ij - λ 2 N ij | = 0 (4)

[0082] wherein,

[0083] ​

[0084] Substituting formulas (5) and (6) into formula (4) allows us to calculate λ.

[0085] S202, the temperature distribution function T * Multiplied by the flow velocity u * Multiply by the radius parameter r * The first integral term is obtained. And calculate the first integral term. The first integral value within the interval from zero to the radius a.

[0086] S203, the flow velocity u * Multiply by the radius parameter r * The second integral term is obtained. And calculate the second integral value of the second integral term within the interval from zero to the radius a.

[0087] S204, Based on the first integral value and the second integral value, determine the average temperature of the nanofluid in the microchannel.

[0088]

[0089] This embodiment also addresses the average temperature. The average temperature after dimensionless processing is obtained. For T b :

[0090]

[0091] In the formula, r = ρ s r * / a.

[0092] Example 3: In this example, step S300 involves determining the Nusselt number (Nu) of the nanofluid in the microchannel based on the average temperature. * The specific steps S301 to S306 are as follows:

[0093] S301, Obtain the nanofluid along the radial direction r of the microchannel. * Temperature distribution function T * And obtain the radius dimension a of the micro-channel.

[0094] T in this embodiment * And T in Example 2 * same.

[0095] S302, regarding the temperature distribution function T* By performing differential calculations with respect to the radius parameter, we obtain the differential expression. Then, the differential expression is applied to the radius dimension to obtain the differential value.

[0096] S303, determine the wall temperature T of the nanofluid at the inner wall of the microchannel. w :

[0097] T w =T * (z * a)

[0098] S304, the wall temperature T w Subtract the average temperature Obtain the temperature difference value

[0099] S305, the differential value Multiplying by the diameter 2a of the microchannel yields the product value.

[0100] S306, Divide the product value by the temperature difference value to obtain the Nusselt number (Nu) of the nanofluid in the microchannel. * :

[0101]

[0102] This embodiment also addresses the Nusel number Nu. * The Nusselt number (Nu) is obtained by dimensionless transformation. * For Nu:

[0103]

[0104] In practical applications, the flow velocity u * It is related to the nanoparticle volume concentration φ, that is, the nanoparticle volume concentration φ affects the flow velocity u. * This is because φ affects the flow index n and fluid consistency m in formula (1). The relationship between φ and n and m is shown in Table 1:

[0105] Table 1

[0106]

[0107]

[0108] The following example illustrates how the flow velocity u can be calculated using formula (1). * When p * 10 5When Pa / m and the nanoparticle volume concentration φ is 0%, 1%, 3%, and 5%, along the radius r * The various positions along the direction (the first column in Table 2 is along radius r) * The flow velocity u of the nanofluid at various positions in the direction * As shown in Table 2. For example, when p * 10 5 When Pa / m and the nanoparticle volume concentration φ is 0%, along the radius r * The flow velocity u at a distance of 0.0000001m from the center of the cross-section of the microtube. * It is 1.27E-05m / s.

[0109] Table 2

[0110]

[0111]

[0112] When p * 10 6 When Pa / m and the nanoparticle volume concentration φ is 0%, 1%, 3%, and 5%, along the radius r * The various positions along the direction (the first column in Table 3 is along the radius r) * The flow velocity u of the nanofluid at various positions in the direction * As shown in Table 3:

[0113] Table 3

[0114]

[0115] When radius a is 10 -6 m and sliding length 10 -8 The volumetric flow rate varies with the pressure gradient -dp when the nanoparticle volume concentration φ is 0%, 1%, 3%, and 5%. * The changes in / dz are shown in Table 4:

[0116] Table 4

[0117]

[0118] When the microtubule radius a is 10 -5 m, slip length 10 -8 Table 5 shows the variation of volumetric flow rate with pressure gradient when the volumetric concentration φ of nanoparticles is 0%, 1%, 3%, and 5%, respectively:

[0119] Table 5

[0120]

[0121]

[0122] The nanoparticle volume concentration φ is fixed at 5%, and P is fixed at 2 x 10 6 Pam, the variation of Nu with slip length As shown in Table 6, when the relative slip length and 0.1, the variation of Nu in the axial direction. It can be seen that the local Nu number decreases with the increase of z value and finally tends to a constant value. The length of the entrance section corresponding to different slip lengths is shown to be essentially unchanged. However, for any fixed z, Nu increases with the increase of nanoparticle concentration. This phenomenon can be explained from the variation of the velocity of the nanofluid near the tube wall. From the theoretical analysis, it can be seen that if the pressure gradient and the nanoparticle concentration are assumed to be constant, the flow velocity at the wall will increase with the increase of the slip length, that is, a larger slip length can promote the flow of the nanofluid on the boundary and thus strengthen the heat transfer. It can be concluded that the increase of the slip length can improve the heat transfer efficiency of the nanofluid in the microtube.

[0123] Table 6

[0124]

[0125]

[0126] The variation of Nusselt number with the relative slip length in the fully developed section of the nanofluid corresponding to φ = 0, 1%, 3%, 5% under two different boundary conditions of the equal wall temperature and the equal heat flux. It can be found from Table 7 that under the two boundary conditions, the heat transfer efficiency of the nanofluid in the fully developed section increases with the increase of the particle concentration and the slip length under the equal heat flux boundary condition. For a fixed fluid, the heat transfer efficiency under the equal wall temperature boundary condition is higher than that under the equal heat flux boundary condition. In addition, for each fixed particle concentration, the distance between the two curves corresponding to the two different boundary conditions increases with the increase of the slip length.

[0127] Table 7

[0128]

[0129]

[0130] The embodiment also provides a device for analyzing the heat transfer characteristics of a nanofluid, as shown in FIG. 6, which comprises the following components: Figure 2

[0131] ​The flow velocity calculation module 01 is configured to obtain a slip length between a micro-pipe and the nanofluid, obtain fluid attribute information of the nanofluid, and obtain pipe attribute information of the micro-pipe, and apply a velocity calculation formula constructed based on a power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain a flow velocity of the nanofluid in the micro-pipe.

[0132] The average temperature calculation module 02 is configured to determine an average temperature of the nanofluid in the micro-pipe based on the flow velocity.

[0133] The Nusselt number calculation module 03 is configured to determine a Nusselt number of the nanofluid in the micro-pipe based on the average temperature.

[0134] Based on the above embodiment, the present application further provides a terminal device, and a principle block diagram of the terminal device can be as shown in Figure 3 The terminal device includes a processor, a memory, a network interface, and a display screen connected through a system bus. The processor of the terminal device is configured to provide calculation and control capabilities. The memory of the terminal device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for running the operating system and the computer program in the non-volatile storage medium. The network interface of the terminal device is configured to communicate with an external terminal through a network connection. The computer program is executed by the processor to implement a nanofluid heat transfer characteristic analysis method. The display screen of the terminal device can be a liquid crystal display screen or an electronic ink display screen.

[0135] Those skilled in the art can understand that Figure 3 The principle block diagram shown in the above embodiment is only a block diagram of part of the structure related to the present application scheme, and does not constitute a limitation on the terminal device to which the present application scheme is applied. Specifically, the terminal device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0136] In one embodiment, a terminal device is provided, which includes a memory, a processor, and a nanofluid heat transfer characteristic analysis method program stored in the memory and executable on the processor. When the processor executes the nanofluid heat transfer characteristic analysis method program, the following operation instructions are implemented:

[0137] obtain a slip length between a micro-pipe and the nanofluid, obtain fluid attribute information of the nanofluid, and obtain pipe attribute information of the micro-pipe, and apply a velocity calculation formula constructed based on a power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain a flow velocity of the nanofluid in the micro-pipe.

[0138] determining an average temperature of the nanofluid in the micro-pipe based on the flow velocity;

[0139] determining a Nusselt number of the nanofluid in the micro-pipe based on the average temperature.

[0140] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, storage, database or other medium used in the embodiments of the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0141] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for analyzing the heat transfer characteristics of a nanofluid, wherein the heat transfer characteristics include the flow velocity and average temperature of the nanofluid in a pipe, and the Nusselt number, characterized in that, The method comprises the following steps: obtaining the slip length between the micro-pipe and the nanofluid, obtaining the fluid attribute information of the nanofluid, and obtaining the pipe attribute information of the micro-pipe, and applying a velocity calculation formula constructed based on a power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain the flow velocity of the nanofluid in the micro-pipe; based on the flow velocity, determining the average temperature of the nanofluid in the micro-pipe; based on the average temperature, determining the Nusselt number of the nanofluid in the micro-pipe; applying the velocity calculation formula constructed based on the power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain the flow velocity of the nanofluid in the micro-pipe, comprising: determining the flow index and fluid consistency in the fluid attribute information; determining the critical strain rate and wall strain rate and size data in the pipe attribute information; applying the velocity calculation formula constructed based on the power-law fluid model to the slip length, the flow index, the fluid consistency, the critical strain rate, the wall strain rate, and the size data to obtain the flow velocity of the nanofluid in the micro-pipe; based on the flow velocity, determining the average temperature of the nanofluid in the micro-pipe, comprising: obtaining the temperature distribution function of the nanofluid along the radial direction of the micro-pipe, and obtaining the radius size of the micro-pipe; multiplying the temperature distribution function by the flow velocity and then by the radius parameter to obtain a first integral term, and calculating a first integral value of the first integral term in the interval of zero to the radius size; multiplying the flow velocity by the radius parameter to obtain a second integral term, and calculating a second integral value of the second integral term in the interval of zero to the radius size; determining the average temperature of the nanofluid in the micro-pipe according to the first integral value and the second integral value; based on the average temperature, determining the Nusselt number of the nanofluid in the micro-pipe, comprising: obtaining the temperature distribution function of the nanofluid along the radial direction of the micro-pipe, and obtaining the radius size of the micro-pipe; performing differential calculation on the temperature distribution function with respect to the radius parameter to obtain a differential expression, and applying the differential expression to the radius size to obtain a differential value; determining the wall temperature of the nanofluid at the inner wall of the micro-pipe; obtaining the Nusselt number of the nanofluid in the micro-pipe according to the average temperature, the wall temperature, and the differential value; the construction method of the velocity calculation formula, comprising: determining the rheological property of the nanofluid based on the power-law fluid model; determining the slip boundary condition of the nanofluid; constructing the velocity calculation formula according to the rheological property and the slip boundary condition.

2. The method of claim 1, wherein the nanofluid is a mixture of water and nanoparticles. obtaining the Nusselt number of the nanofluid in the micro-pipe according to the average temperature, the wall temperature, and the differential value, comprising: subtracting the average temperature from the wall temperature to obtain a temperature difference value; multiplying the differential value by a diameter of the micro-pipe to obtain a product value; dividing the product value by the temperature difference value to obtain a Nusselt number of the nanofluid in the micro-pipe.

3. The method of claim 1 or 2, wherein the nanofluid is a mixture of water and nanoparticles. The flow velocity, the average temperature, and the Nusselt number are respectively subjected to dimensionless processing.

4. A nanofluid heat transfer characteristic analysis device, characterized by, The device comprises the following components: a flow velocity calculation module, configured to acquire a slip length between a micro-pipe and the nanofluid, acquire fluid attribute information of the nanofluid, acquire pipe attribute information of the micro-pipe, and apply a velocity calculation formula constructed based on a power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain a flow velocity of the nanofluid in the micro-pipe; an average temperature calculation module, configured to determine an average temperature of the nanofluid in the micro-pipe based on the flow velocity; a Nusselt number calculation module, configured to determine a Nusselt number of the nanofluid in the micro-pipe based on the average temperature; applying the velocity calculation formula constructed based on the power-law fluid model to the slip length, the fluid attribute information, and the pipe attribute information to obtain the flow velocity of the nanofluid in the micro-pipe comprises: determining a flow index and a fluid consistency in the fluid attribute information; determining a critical strain rate and a wall strain rate and size data in the pipe attribute information; applying the velocity calculation formula constructed based on the power-law fluid model to the slip length, the flow index, the fluid consistency, the critical strain rate, the wall strain rate, and the size data to obtain the flow velocity of the nanofluid in the micro-pipe; determining the average temperature of the nanofluid in the micro-pipe based on the flow velocity comprises: acquiring a temperature distribution function of the nanofluid along a radial direction of the micro-pipe, and acquiring a radius size of the micro-pipe; multiplying the temperature distribution function by the flow velocity and then by a radius parameter to obtain a first integral term, and calculating a first integral value of the first integral term in an interval of zero to the radius size; multiplying the flow velocity by a radius parameter to obtain a second integral term, and calculating a second integral value of the second integral term in the interval of zero to the radius size; determining the average temperature of the nanofluid in the micro-pipe according to the first integral value and the second integral value; determining the Nusselt number of the nanofluid in the micro-pipe based on the average temperature comprises: acquiring a temperature distribution function of the nanofluid along a radial direction of the micro-pipe, and acquiring a radius size of the micro-pipe; performing differential calculation on the temperature distribution function with respect to a radius parameter to obtain a differential expression, and applying the differential expression to the radius size to obtain a differential value; determining a wall temperature of the nanofluid at an inner wall surface of the micro-pipe; obtaining the Nusselt number of the nanofluid in the micro-pipe according to the average temperature, the wall temperature, and the differential value; the velocity calculation formula is constructed in the following manner: determining rheological properties of the nanofluid based on the power-law fluid model; determining slip boundary conditions of the nanofluid; constructing a velocity calculation formula according to the rheological properties and the slip boundary conditions.

5. A terminal device, characterized by, The terminal device comprises a memory, a processor, and a nanofluid heat transfer characteristic analysis program stored in the memory and executable on the processor. When the processor executes the nanofluid heat transfer characteristic analysis program, the steps of the nanofluid heat transfer characteristic analysis method according to any one of claims 1-3 are implemented.

6. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a nanofluid heat transfer characteristic analysis program. When the processor executes the nanofluid heat transfer characteristic analysis program, the steps of the nanofluid heat transfer characteristic analysis method according to any one of claims 1-3 are implemented.

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