Method for calculating comprehensive heat transfer coefficient of wall surface of circumferential heating appliance

Abstract

The invention discloses a comprehensive heat transfer coefficient calculation method for the wall surface of a circumferential heating appliance, and the calculation method specifically comprises the following steps: A, carrying out the simplified coupling processing of a radiation heat transfer formula and a convective heat transfer formula according to the physical parameters of a heat dissipation assembly, and obtaining a comprehensive heat transfer coefficient model of the heat dissipation assembly; b, on the basis of the comprehensive heat transfer coefficient model, temperature simulation calculation is conducted on the wall surface temperature Tw of the outer wall of the heat dissipation assembly by means of the environment temperature T0 and the total heat transfer amount Q of the circumferential heating appliance; and C, the temperature simulation processing of the wall surface temperature Tw is presented through a visualization system. The comprehensive heat transfer coefficient calculation method is established by researching the comprehensive heat transfer coefficient of the wall surface of the circumferential heating appliance, convective heat transfer and radiative heat transfer calculation is simplified, the comprehensive heat transfer coefficient of the wall surface is directly set in non-gridding rapid simulation, the calculation time is greatly shortened compared with the prior art, the operation is simple, and the calculation efficiency is high. And rapid and efficient design optimization of the circumferential heating appliance is realized.

Description

Technical Field

[0001] The invention relates to the field of heating smoking device simulation, and in particular to a method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall. Background Art

[0002] Heat-not-burn tobacco products are products that mainly convert nicotine and other substances in tobacco into vapor through atomization and other means, which are then inhaled by users.

[0003] Among them, the heated smoking device is usually provided with a circumferential heater, which is used to uniformly heat substances such as tobacco or tobacco oil so that they release aroma and nicotine and other components without burning. Such heaters usually have a specific design and structure to ensure uniformity and efficiency of heating.

[0004] At present, the product design and optimization iteration of circumferential heating equipment mainly adopts the traditional R&D method of "design-simulation-proofing-testing", which has problems such as slow R&D progress, limited performance improvement capabilities, and high R&D costs, and cannot meet the needs of the industry for rapid R&D of heating equipment products.

[0005] Among them, the "design" stage lacks heat transfer models for circumferential heating equipment, especially model research on multi-physics field coupling and complex geometric structures, and lacks effective theoretical guidance. In addition, existing research usually only focuses on a single component and ignores the systematic research on the entire device. The "simulation" link also faces the challenges of traditional simulation operations being difficult, slow in calculation speed, low in integration, and poor in integrity. These problems not only prolong the R&D cycle, but also raise the technical threshold.

[0006] Among them, the comprehensive heat transfer coefficient is an important parameter for the natural cooling of the wall of the circumferential heating device. It is mainly affected by natural convection and radiation heat transfer. The comprehensive heat transfer coefficient cannot be directly input in the traditional "simulation". It is usually necessary to set up an open air domain at a certain distance outside the device for comprehensive heat transfer calculation. The calculation time is as long as 48 hours and the simulation operation is cumbersome, and real-time simulation cannot be achieved. Summary of the invention

[0007] In order to solve the above technical problems existing in the prior art, the present invention provides a method for calculating the comprehensive heat transfer coefficient of the wall surface of a circumferential heating device.

[0008] The technical solution adopted by the present invention is:

[0009] A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall surface, characterized in that the calculation method specifically comprises the following steps:

[0010] Step A: According to the physical parameters of the heat dissipation component, the radiation heat transfer formula and the convection heat transfer formula are simplified and coupled to obtain a comprehensive heat transfer coefficient model of the heat dissipation component;

[0011] Step B: Based on the comprehensive heat transfer coefficient model described above, using the ambient temperature T 0 and the total heat transfer Q of the circumferential heating device, the outer wall temperature T of the heat dissipation component w Perform temperature simulation calculations;

[0012] Step C: Set the wall temperature T w The temperature simulation process is presented through a visualization system.

[0013] Furthermore, the step A specifically includes:

[0014] Step A1: simplifying the radiation heat transfer formula according to the physical parameters of the heat dissipation component to obtain a simplified radiation heat transfer rate;

[0015] Step A2: simplifying the convection heat transfer formula according to the physical parameters of the heat dissipation component to obtain a simplified convection heat transfer rate;

[0016] Step A3: coupling the simplified radiation heat transfer rate and the simplified convection heat transfer rate to obtain a comprehensive heat transfer coefficient model of the heat dissipation component.

[0017] Furthermore, the temperature simulation calculation is a gridless fast simulation calculation;

[0018] Furthermore, the heating smoking device is a circumferential heating device, the heating component is a tubular heating element; the heat insulation component is a tubular heat insulation element sleeved on the outside of the tubular heating element; the heat dissipation component is a heat dissipation shell sleeved on the outside of the tubular heat insulation element.

[0019] Furthermore, the step A1 specifically includes:

[0020] Step A11: Set the outer wall temperature T w Take two end values ​​and at least one intermediate value in the range of 25-60°C, and substitute them into the radiation heat transfer formula to calculate the surface temperature T of each outer wall. w The corresponding radiation heat transfer rate a R1 ;

[0021] Step A12: According to the temperature T of each outer wall w The corresponding radiation heat transfer rate Q R , get Q R About T w The first fitting formula of the simplified radiation heat transfer rate α is obtained R3 .

[0022] Furthermore, the radiation heat transfer formula is:

[0023]

[0024] Among them, Q R is the radiation heat transfer heat flux, δ 0 is the Stephen Borhertz constant [5.67*10 -8 w / (m 2 ·k 4 )], ε is the total emissivity of the material, S is the wall area of ​​the device, is the view factor, T w is the wall temperature, T 0 is the ambient temperature.

[0025] Furthermore, the step A12 is specifically as follows:

[0026] Step A121: Simplify the radiation heat transfer formula to:

[0027] Q R =α R1 S(T w -T 0 ) (2)

[0028] Among them, α R is the radiation heat transfer coefficient, S is the wall area of ​​the device, T w is the wall temperature, T 0 is the ambient temperature;

[0029] Step A122: Based on the ambient temperature T 0 , determine the view factor is 1, and substituting it into the radiation heat transfer formula, we get the following formula:

[0030]

[0031] Among them, α R is the radiation heat transfer coefficient, δ 0 is the Stephen Borhertz constant [5.67*10 -8 w / (m 2 ·k 4 )], ε is the total emissivity of the material, T w is the wall temperature, T 0 is the ambient temperature;

[0032] Step A123: Set the ambient temperature T 0 is 20℃, the wall temperature is 25~60℃, the total wall emissivity is 0.2~0.8, and the wall temperature T is calculated. w and radiation heat transfer coefficient αR relation;

[0033] Step A124: According to the wall temperature T w and radiation heat transfer coefficient α R Relationship, it is determined that the radiation heat transfer coefficient can be expressed as the product of the basic radiation heat transfer coefficient and the emissivity, and the following radiation heat transfer rate α is obtained R2 :

[0034] α R2 =ε(5.0364+0.0325T w ) (4)

[0035] Where ε is the total emissivity of the material, T w is the wall temperature;

[0036] Step A125: According to the wall temperature T w With the radiation heat transfer rate α R 2 and the relationship between the total material emissivity ε and the radiation heat transfer rate α R 2, the radiation heat transfer rate α R 2 The fitting is simplified and the following simplified radiation heat transfer rate α is obtained R3 :

[0037] α R3 =Aε (5)

[0038] Where A is the wall temperature T w The relative scaling factor within a preset temperature range.

[0039] Furthermore, the step A2 specifically includes:

[0040] Step A21: according to the wall shapes, sizes and / or orientations of different heat dissipation components, substitute the convection heat transfer formulas to calculate the radiation heat transfer rates corresponding to the wall types;

[0041] Step A22: Simplify the radiation heat transfer rate into the wall type parameter L and the outer wall temperature T w function.

[0042] Furthermore, the convective heat transfer formula is:

[0043] Q C =α c1 S(T w -T 0 ) (6)

[0044] Among them, Q C is the convective heat flux, α c1 is the convection heat transfer coefficient, S is the wall area of ​​the equipment, Tw is the wall temperature, T 0 is the ambient temperature.

[0045] Furthermore, the step A21 includes:

[0046] Step A211: Based on the Rayleigh number or Nusselt number formula, the relationship between the convective heat transfer coefficient and the wall temperature and size corresponding to the convective surface facing upward, the heat surface facing downward and the vertical wall is processed, and the convective heat transfer coefficient corresponding to different flat walls is obtained by substituting the convective heat transfer formula into the convective heat transfer coefficient:

[0047]

[0048] Among them, α P,T is the convective heat transfer coefficient of the flat wall with the hot surface facing upward, α P,B is the convective heat transfer coefficient of the flat wall with the hot surface facing downward, α P，v is the convective heat transfer coefficient of the vertical wall, T w is the wall temperature, W is the wall width, and H is the wall height;

[0049] Step A212: Based on the Rayleigh number or Nusselt number formula, the relationship between the convective heat transfer coefficient and the wall temperature and size corresponding to the horizontal cylindrical wall and the spherical wall is processed, and the convective heat transfer coefficient corresponding to different curved walls is obtained by substituting the convective heat transfer formula into the convective heat transfer formula:

[0050]

[0051] Among them, α Cy is the convection heat transfer coefficient of the horizontal cylindrical wall, α S is the convection heat transfer coefficient of the spherical wall, and R is the radius of the curved surface.

[0052] Furthermore, the step A22 specifically includes:

[0053] Step A221: Simplify the convective heat transfer coefficient corresponding to the flat wall and the convective heat transfer coefficient corresponding to the curved wall to obtain:

[0054]

[0055] Among them, the coefficient B is the proportionality coefficient related to the wall type, T w is the wall temperature, and L is a size parameter related to the wall type.

[0056] Furthermore, the comprehensive heat transfer coefficient model is:

[0057] α T =α R3 +α C (13)

[0058] Among them, α T is the comprehensive heat transfer coefficient, α R3 To simplify the radiation heat transfer rate, α C To simplify the convection heat transfer rate.

[0059] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0060] 1. The present invention studies the comprehensive heat transfer coefficient of the wall of the circumferential heating device, establishes a calculation method for the comprehensive heat transfer coefficient, simplifies the calculation of convective heat transfer and radiation heat transfer, and directly sets the wall comprehensive heat transfer coefficient in the gridless fast simulation. The calculation time is greatly shortened compared with the existing technology and the operation is simple, which realizes fast and efficient design optimization of the circumferential heating device, and provides a set of fast and effective methods for the design and development of circumferential heating devices in the industry.

[0061] 2. The present invention aims to solve the bottleneck problems existing in the research and development of existing circumferential heating devices. By studying the heat transfer simulation characteristics and systematic parameters of the heating devices, including the comprehensive wall heat transfer coefficient, contact thermal resistance, heat transfer in a small space, etc., the radiation heat transfer formula and the convection heat transfer formula are simplified and coupled to construct a comprehensive heat transfer coefficient model suitable for circumferential heating devices.

[0062] 3. The present invention is based on a comprehensive heat transfer coefficient model, and constructs a gridless rapid simulation system for thermal design guidance, material selection and rapid simulation evaluation, forming a method for rapid iteration of the "design" and "simulation" links to shorten the R&D cycle of circumferential heating equipment and improve the optimization efficiency of the design. At the same time, it provides real-time feedback and intuitive visualization results, greatly accelerating the iteration speed of equipment design. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a flow chart of the method for calculating the comprehensive heat transfer coefficient of the wall surface of the circumferential heating device of the present invention;

[0064] Figure 2 is the wall temperature Tw and the radiation heat transfer coefficient α in the embodiment R Schematic diagram of the relationship;

[0065] Figure 3 is a cloud diagram of air temperature for heat transfer on a wall with the hot surface facing upwards in the embodiment;

[0066] Figure 4 is a cloud diagram of air temperature for heat transfer on a wall with the hot side facing downward in the embodiment;

[0067] Figure 5 is a cloud diagram of air temperature for heat transfer on a vertical flat wall in an embodiment;

[0068] Figure 6Schematic diagram of the relationship between the heat transfer coefficient of the wall facing upward and the wall size in the embodiment;

[0069] Figure 7 Schematic diagram of the relationship between the heat transfer coefficient of the wall facing upward and the wall temperature in the embodiment;

[0070] Figure 8 Schematic diagram of the relationship between the heat transfer coefficient of the wall facing downward with the hot surface and the wall size in the embodiment;

[0071] Fig. 9 Schematic diagram of the relationship between the heat transfer coefficient of the wall facing downward with the hot surface and the wall temperature in the embodiment;

[0072] Fig.10 is a schematic diagram of the relationship between the vertical flat wall convection heat transfer coefficient and the wall size in an embodiment;

[0073] Fig.11 is a schematic diagram of the relationship between the vertical flat wall convection heat transfer coefficient and the wall temperature in the implementation mode;

[0074] Fig.12 is a cloud diagram of air temperature for heat transfer on a curved surface in an implementation manner;

[0075] Fig.13 is a schematic diagram of the relationship between the convective heat transfer coefficient of a horizontal cylinder and the wall size in an embodiment;

[0076] Fig.14 is a schematic diagram of the relationship between the convective heat transfer coefficient of a horizontal cylinder and the wall temperature in an embodiment;

[0077] Fig.15 Schematic diagram of the relationship between the heat transfer coefficient of the curved surface and the wall size in the embodiment;

[0078] Fig.16 Schematic diagram of the relationship between the surface heat transfer coefficient and the wall temperature in the embodiment;

[0079] Fig.17 is a simulation schematic diagram in which the material of the circumferential heating device shell is set to PEEK during the non-gridding fast simulation process in the implementation method;

[0080] Fig.18 is a simulation schematic diagram of a circumferential heating device fluid region being set to air during a non-gridding fast simulation process in an implementation manner;

[0081] Fig.19 is a simulation schematic diagram of using the comprehensive heat transfer coefficient in the meshless fast simulation process in the implementation method as an input simulation calculation of the boundary condition of the circumferential heating device;

[0082] Fig. 20is a schematic diagram of solving a circumferential heating tool in a meshless fast simulation process in an implementation method;

[0083] Fig.21 It is a simulation schematic diagram of the temperature field of the circumferential heating tool after the solution is completed in the mesh-free fast simulation process in the implementation method, and real-time feedback;

[0084] Fig. 22 It is a comparison chart between the fast simulation calculation results and the experimental measurement values ​​in the implementation method. DETAILED DESCRIPTION

[0085] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0086] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0087] The present invention will be described in detail below in conjunction with exemplary embodiments with reference to the accompanying drawings.

[0088] The present invention provides a method for calculating the comprehensive heat transfer coefficient of the wall surface of a circumferential heating device, wherein the circumferential heating device includes a heating component, a heat insulation component and a heat dissipation component, such as Figure 1 As shown, the comprehensive heat transfer coefficient calculation method specifically includes the following steps:

[0089] Step A: According to the physical parameters of the heat dissipation component, the radiation heat transfer formula and the convection heat transfer formula are simplified and coupled to obtain a comprehensive heat transfer coefficient model of the heat dissipation component.

[0090] Step B: Based on the comprehensive heat transfer coefficient model, using the ambient temperature T 0 , the total heat transfer Q of the heating device to the outer wall temperature T of the heat dissipation component w Perform temperature simulation calculations.

[0091] Step C: Set the wall temperature T w The temperature simulation process is presented through a visualization system.

[0092] Exemplarily, the physical parameters of the heat dissipation component may be information such as the wall area of ​​the heat dissipation component and the emissivity of the wall material.

[0093] It can be understood that by fitting some data with less influence through the physical parameters of the heat dissipation components, the originally more complex radiation heat transfer formula and convection heat transfer formula are simplified and coupled to obtain a comprehensive heat transfer coefficient model, and then subsequent calculations are directly performed through the comprehensive heat transfer coefficient model, which can effectively improve the calculation efficiency.

[0094] Specifically, step A includes:

[0095] Step A1: Simplify the radiation heat transfer formula according to the physical parameters of the heat dissipation component to obtain the simplified radiation heat transfer rate α R2 ;

[0096] Step A2: Simplify the convection heat transfer formula according to the physical parameters of the heat dissipation component to obtain the simplified convection heat transfer rate α C ;

[0097] Step A3: Simplify the radiation heat transfer rate α R2 and the simplified convection heat transfer rate α C The coupling process is performed to obtain the comprehensive heat transfer coefficient model of the heat dissipation component.

[0098] Specifically, step A1 includes:

[0099] Step A11: Set the outer wall temperature T w Take two end values ​​and at least one intermediate value in the range of 25-60℃, and substitute them into the radiation heat transfer formula to calculate the surface temperature T of each outer wall. w The corresponding radiation heat transfer rate a R1 ;

[0100] Step A12: According to the temperature T of each outer wall w The corresponding radiation heat transfer rate Q R , get Q R About T w The first fitting formula of the simplified radiation heat transfer rate α is obtained R3 .

[0101] Specifically, the radiation heat transfer formula is:

[0102]

[0103] Among them, Q R is the radiation heat transfer heat flux, δ 0 is the Stephen Borhertz constant [5.67*10 -8 w / (m 2 ·k 4 )], ε is the total emissivity of the material, S is the wall area of ​​the device, is the view factor, T w is the wall temperature, T 0 is the ambient temperature.

[0104] Specifically, step A12 is as follows:

[0105] Step A121: Simplify the radiation heat transfer formula to:

[0106] Q R=α R1 S(T w -T 0 ) (2)

[0107] Among them, α R is the radiation heat transfer coefficient, S is the wall area of ​​the device, T w is the wall temperature, T 0 is the ambient temperature;

[0108] Step A122: Based on the ambient temperature T 0 , determine the view factor 1, and substitute it into the radiation heat transfer formula to obtain the following formula:

[0109]

[0110] Among them, α R is the radiation heat transfer coefficient, δ 0 is the Stephen Borhertz constant [5.67*10-8w / (m 2 ·k4)], ε is the total emissivity of the material, T w is the wall temperature, T 0 is the ambient temperature;

[0111] Step A123: Set the ambient temperature T 0 is 20℃, the wall temperature is 25~60℃, the total wall emissivity is 0.2~0.8, and the wall temperature T is calculated. w and radiation heat transfer coefficient α R relation;

[0112] Step A124: According to the wall temperature T w and radiation heat transfer coefficient α R Relationship, it is determined that the radiation heat transfer coefficient can be expressed as the product of the basic radiation heat transfer coefficient and the emissivity, and the following radiation heat transfer rate α is obtained R2 :

[0113] α R2 =ε(5.0364+0.0325T w ) (4)

[0114] Where ε is the total emissivity of the material, T w is the wall temperature;

[0115] Step A125: According to the wall temperature T w and the radiation heat transfer rate α R2 The relationship between the total emissivity ε of the material and the radiation heat transfer rate α R2 The relationship between the radiation heat transfer rate α R2 The fitting is simplified to obtain the following simplified radiation heat transfer rate α R3 :

[0116] α R3 =Aε (5)

[0117] Where A is the wall temperature T w The relative scaling factor within a preset temperature range.

[0118] Specifically, step A2 includes:

[0119] Step A21: according to the wall shapes, sizes and / or orientations of different heat dissipation components, substitute them into the convection heat transfer formula to calculate the radiation heat transfer rate corresponding to each wall type;

[0120] Step A22: Simplify the radiation heat transfer rate into the wall type parameter L and the outer wall temperature T w function.

[0121] Specifically, the convective heat transfer formula is:

[0122] Q C =α c1 S(T w -T 0 ) (6)

[0123] Among them, Q C is the convective heat flux, α c1 is the convection heat transfer coefficient, S is the wall area of ​​the equipment, T w is the wall temperature, T 0 is the ambient temperature.

[0124] Specifically, step A21 includes: step A211: based on the Rayleigh number or Nusselt number formula, the relationship between the convective heat transfer coefficient and the wall temperature and size corresponding to the convective surface facing upward, the heat surface facing downward and the vertical wall is processed, and the convective heat transfer coefficient corresponding to different flat walls is obtained by substituting them into the convective heat transfer formula:

[0125]

[0126] Among them, α P，T is the convective heat transfer coefficient of the flat wall with the hot surface facing upward, α P，B is the convective heat transfer coefficient of the flat wall with the hot surface facing downward, α P，v is the convective heat transfer coefficient of the vertical wall, T w is the wall temperature, W is the wall width, and H is the wall height;

[0127] Step A212: Based on the Rayleigh number or Nusselt number formula, the relationship between the convective heat transfer coefficient and the wall temperature and size corresponding to the horizontal cylindrical wall and the spherical wall is processed, and substituted into the convective heat transfer formula to obtain the convective heat transfer coefficient corresponding to different curved walls:

[0128]

[0129] Among them, α Cy is the convection heat transfer coefficient of the horizontal cylindrical wall, α S is the convection heat transfer coefficient of the spherical wall, and R is the radius of the curved surface.

[0130] Specifically, step A22 includes:

[0131] Step A221: Simplify the convective heat transfer coefficient corresponding to the flat wall and the convective heat transfer coefficient corresponding to the curved wall to obtain:

[0132]

[0133] Among them, the coefficient B is the proportionality coefficient related to the wall type, T w is the wall temperature, and L is a size parameter related to the wall type.

[0134] Specifically, the comprehensive heat transfer coefficient model is:

[0135] α T =α R2 +α C (13)

[0136] Among them, α T is the comprehensive heat transfer coefficient, α R2 To simplify the radiation heat transfer rate, α C To simplify the convection heat transfer rate.

[0137] Specifically, the temperature simulation calculation of the present invention is a gridless fast simulation calculation.

[0138] Specifically, the heating component is a tubular heating element; the heat insulation component is a tubular heat insulation element sleeved on the outside of the tubular heating element; and the heat dissipation component is a heat dissipation shell sleeved on the outside of the tubular heat insulation element.

[0139] To facilitate understanding of the inventive concept of the present invention, the specific implementation process of the present invention will be described below in conjunction with specific embodiments.

[0140] The implementation process can generally include the following:

[0141] 1. Obtain the wall convection heat transfer rate equation and the wall radiation heat transfer rate equation.

[0142] 2. Study the radiation heat transfer coefficient of the wall of the circumferential heating device and obtain a simplified equation.

[0143] 3. Study the convective heat transfer coefficient of the wall of the circumferential heating device and obtain a simplified equation.

[0144] 4. Obtain the simplified equation of comprehensive heat transfer coefficient and calculate the comprehensive heat transfer coefficient.

[0145] 5. The application of comprehensive heat transfer coefficient in meshless fast simulation, including standardized simulation operation processes such as model processing, material selection, and boundary condition setting. Compared with traditional simulation, meshless fast simulation simplifies highly professional steps such as mesh processing and solution setting. Among them, the comprehensive heat transfer coefficient is used as the boundary condition input of the outer wall of the circumferential heating device, which provides a theoretical basis for real-time heat transfer simulation of the device.

[0146] 6. Compared with traditional simulation, gridless fast simulation can obtain heat transfer simulation feedback of the equipment in a very short time (2 minutes): information such as the overall temperature field and local temperature values.

[0147] 7. Build a comprehensive heat transfer coefficient testing platform.

[0148] 8. Verify the heat transfer simulation results of the equipment using the simplified method of comprehensive heat transfer coefficient.

[0149] Specifically, it may include the following:

[0150] Step 1. It is known that the wall temperature of the circumferential heating device is usually higher than the room temperature. Heat is dissipated from the wall to the environment by convection and radiation. The total heat transfer equation from the wall to the environment can be expressed as:

[0151] Q=Q C +Q R (14)

[0152] Among them, Q C is the convective heat flux, Q R is the radiation heat transfer heat flux;

[0153] Step 2. It is known that the convective heat transfer rate equation can be expressed as:

[0154] Q C =α c S(T w -T 0 ) (6)

[0155] Among them, α c is the convection heat transfer coefficient, S is the wall area of ​​the equipment, Tw is the wall temperature, and T0 is the ambient temperature;

[0156] Step 3. The radiation heat transfer rate equation can be expressed as:

[0157]

[0158] Among them, δ 0 is the Stephen Borhertz constant [5.67*10-8w / (m2 ·k4)], ε is the total emissivity of the material, S is the wall area of ​​the device, is the angular coefficient, Tw is the wall temperature, and T0 is the ambient temperature;

[0159] Step 4. Change equation (3) into the form of equation (2), that is

[0160] Q R =α R S(T w -T 0 ) (2)

[0161] where α R is the radiation heat transfer coefficient, S is the wall area of ​​the device, Tw is the wall temperature, and T0 is the ambient temperature;

[0162] Step 5. According to step 1, the total heat transfer equation from the wall to the environment can be simplified as follows:

[0163] Q=Q C +Q R =α T S(T w -T 0 ) (15)

[0164] where α T is the comprehensive heat transfer coefficient, S is the wall area of ​​the device, Tw is the wall temperature, and T0 is the ambient temperature;

[0165] Step 6. According to step 5, simplify the total wall heat transfer equation to obtain the comprehensive heat transfer coefficient expression:

[0166] α T =α c +a R (16)

[0167] Among them, α c is the convective heat transfer coefficient, α R is the radiation heat transfer coefficient;

[0168] Step 7. During the use of the circumferential heating device, the outer wall is usually higher than the ambient temperature, and the surrounding environment is open. The radiation heat transfer is mainly radiated from the wall to the surrounding environment, and the ambient temperature is constant. Therefore, the angular coefficient in the radiation heat transfer rate equation (3) is is 1, α R The radiation heat transfer coefficient can be expressed as:

[0169]

[0170] Step 8. According to the actual operating environment of the circumferential heating device, set the ambient temperature to 20°C, the wall temperature to 25-60°C, and the total wall emissivity to 0.2-0.8 (the total emissivity of most materials is within this range), and calculate the wall temperature Tw and the radiation heat transfer coefficient α R Relationships, such as Figure 2 As shown;

[0171] Step 9. According to step 8, it is found that when the emissivity is 0.2, 0.5, 0.8 and 1.0, the radiation heat transfer coefficient values ​​are all parallel lines, that is, the radiation heat transfer coefficient can be expressed as the product of the basic radiation heat transfer coefficient (ε = 1) and the emissivity. Although the formula contains the fourth power term of temperature, since the δ0 value is very small, the radiation heat transfer rate and temperature of the circumferential heating tool in the range of 25 to 60 ° C can be expressed as a linear relationship:

[0172] α R =ε(5.0364+0.0325T w ) (18)

[0173] Step 10. Find α based on step 9. R The influence of the wall temperature Tw is not obvious, but it is greatly affected by the wall emissivity ε. According to the circumferential heating device wall temperature TW in the range of 25~60℃, the α R The influence of is very small, so formula (18) can be further expressed as:

[0174] α R =6.34ε (19)

[0175] Step 11. Study the relationship between flat wall convection heat transfer and wall temperature and size under different postures. Through simulation, the air temperature cloud diagram of flat wall convection heat transfer with the hot surface upward is preliminarily obtained. Figure 3 The air temperature cloud diagram of the flat wall convective heat transfer with the hot surface facing downward is shown in Figure 4 , and the air temperature cloud diagram of heat transfer on the vertical flat wall is shown in Figure 5 ;

[0176] Step 12. According to step 11, the wall convection heat transfer coefficient under three postures is studied, and the relationship between the flat wall convection heat transfer coefficient with the hot surface upward and the wall temperature and size is obtained. Figure 6 and Figure 7 The relationship between the convection heat transfer coefficient of a flat wall with the hot surface facing downward and the wall temperature and size is shown in Figure 8 and Fig. 9 The relationship between the vertical flat wall convection heat transfer coefficient and the wall temperature and size is shown in Fig.10 and Fig.11 ;

[0177] Step 13. According to the Rayleigh number or Nusselt number formula, the three types of convective heat transfer coefficients of the large space with the hot surface facing up, the hot surface facing down, and the vertical wall at 20°C can be expressed as a power function of the flat wall width and temperature as follows:

[0178]

[0179]

[0180] Where Tw is the wall temperature, W is the wall width, and H is the wall height;

[0181] Step 14. Based on Step 11 and Step 12, further study the surface heat transfer and obtain the air temperature cloud diagram of surface heat transfer. Fig.12 ;

[0182] Step 15. According to step 14, the convective heat transfer coefficient of the horizontal cylinder and the sphere is studied, and the relationship between the convective heat transfer coefficient of the horizontal cylinder and the wall temperature and size is obtained. Fig.13 and Fig.14 The relationship between the surface heat transfer coefficient and the wall temperature and size is shown in the figure Fig.15 and Fig.16 ;

[0183] Step 16. According to the Rayleigh number or Nusselt number formula, the convective heat transfer coefficient of a horizontal cylinder and a spherical surface in a large space at 20°C can be expressed as:

[0184]

[0185] Where R is the radius of the surface;

[0186] Step 17. According to the research on the convection heat transfer coefficient of flat wall and curved surface, the convection heat transfer coefficient of wall can be expressed as:

[0187]

[0188] Among them, the coefficient A is the proportional coefficient related to the wall type, and L is the size parameter related to the wall type.

[0189] Step 18. Most of the outer wall of the circumferential heating device is a flat wall surface, the working temperature is between 30 and 40 ° C, and it is painted. The calculation results of step 10 and step 17 are coupled to obtain a simplified equation for the comprehensive heat transfer coefficient, which is approximately the equation:

[0190] α T =α c +α R =9.6+0.06(T w -T 0 ) (20)

[0191] Where, Tw is the wall temperature and T0 is the ambient temperature;

[0192] Step 19. Since the actual wall temperature of the circumferential heating device is not high and the use environment is mild, it mainly relies on natural convection and radiation heat transfer, so the range of the comprehensive heat transfer coefficient is relatively narrow, and the accuracy of the simplified comprehensive heat transfer calculation fully meets the requirements of thermal simulation design. According to the simplified equation of the comprehensive heat transfer coefficient obtained in step 18, the ambient temperature T0 is between 20 and 25 °C, and the wall temperature Tw is between 30 and 40 °C, and the comprehensive heat transfer coefficient α is calculated. T It is 9~11W / (m2·℃).

[0193] Step 20. According to the overall heat transfer equation Q = α T S(T w -T 0 ), where the comprehensive heat transfer coefficient α is calculated according to the simplified equation T 10W / (m 2 ℃); S is the total area of ​​the wall of the device, which is determined by the device ID design; T0 is the ambient temperature, which is 25℃; by determining the total heat transfer Q of the device, the wall temperature Tw can be obtained. Similarly, by determining the wall temperature Tw, the total heat transfer Q can be obtained. In the simulation link of the circumferential heating device design, the simplified wall comprehensive heat transfer can be determined by the total heat transfer Q, and the wall temperature Tw can be quickly obtained to evaluate the device design results.

[0194] Step 21. By using the meshless fast simulation method for calculation, the two original steps in the traditional simulation process (creating or modifying the geometric model, defining the structural load and boundary conditions) can be combined into one step, and the preliminary designed circumferential heating device model is imported into the simulation platform. The model is simplified or modified while defining the design operating environment, that is, the contact mode between the internal structural parts of the circumferential heating device, the heat transfer form in a small space, etc. are simplified and equivalently processed, and the material properties of each solid component are set, such as Fig.17 (For example, the heating element is made of stainless steel 304, the shell is made of PEEK, etc.), and the extracted fluid volume is set to air, such as Fig.18 At the same time, according to step 19, the wall heat transfer is simplified to a comprehensive wall heat transfer coefficient of 10W / (m 2 ·℃), the heat transfer of the heating element is set to solid heat transfer, the temperature is 250℃, that is, the total heat transfer capacity Q of the device is determined, such as Fig.19 .

[0195] Step 22. After completing the above steps, click Solve to automatically trigger the next two steps in the traditional simulation process (create or update the grid, select or start the solver), such as Fig.15The entire process of meshless fast simulation runs completely automatically without requiring much operation.

[0196] Step 23. After waiting for less than 1 minute, the heat transfer simulation results of the circumferential heating device can be immediately displayed on the screen in the form of a temperature cloud map. Fig. 20 The temperature cloud map can be used to visually obtain the overall heat transfer of the equipment, and the local temperature value of the equipment can also be obtained. The highest temperature of the equipment wall is 50.7℃.

[0197] Step 24. The meshless fast simulation method can flexibly adapt to any changes in the simulation input, such as processing the geometry or reselecting materials or further modifying the simulation boundary condition input, and the simulation results will be automatically updated. In this case, the fidelity (i.e. the accuracy of the calculation results) is further adjusted. After waiting for about 30 seconds, the adjusted simulation results are immediately displayed on the screen in the form of a temperature cloud map.

[0198] Step 25. According to the principle of comprehensive heat transfer coefficient, build a comprehensive heat transfer coefficient test platform. Place the sample in a heating device, measure the temperature of the sample surface and the environment, and calculate the comprehensive heat transfer coefficient of the sample. The test platform consists of the following parts:

[0199] ① Sample stage, used to fix the sample and fix the heating device to be tested in the environment;

[0200] ② Constant environmental conditions, constant temperature and humidity room, keep the room temperature at 25℃;

[0201] ③ The heating control device sets the working power according to the working temperature of the heating element of the circumferential heater being 250°C;

[0202] ④Data acquisition and processing system, the data acquisition is mainly the wall temperature of the circumferential heating device, such as Fig.21 shown.

[0203] Step 26. The calculation result of the wall temperature of the circumferential heating device in step 23 is verified based on the comprehensive heat transfer coefficient test platform built in step 25. The experimental test value is 48.3°C, which is close to the simulation calculation value of 50.7°C. At the same time, the actual test results show that the output power consumption (total heat transfer) of the heating element of the device is 2.9W, which is close to the total heat transfer of the heating element of the device in the simulation process. 3.1W; that is, the simplified comprehensive heat transfer coefficient is reliable in the fast simulation calculation application, such as Fig. 22 shown.

[0204] It can be understood that for circumferential heating devices, since the wall temperature is not high and the use environment is mild, natural convection and radiation heat transfer are the main methods, so the range of the comprehensive heat transfer coefficient is relatively narrow, and the accuracy of the simplified comprehensive heat transfer calculation fully meets the requirements of thermal simulation design. T=9.6+0.06(T w -T 0 ) The comprehensive heat transfer coefficient of the circumferential heating device is directly obtained in the range of 9 to 11 W / (m2·℃), which simplifies the steps of setting an open air domain at a certain distance outside the device to calculate the comprehensive heat transfer value. The comprehensive heat transfer coefficient can be directly used to calculate the heat dissipation capacity of the device. At the same time, based on the establishment of a gridless fast simulation system, the grid processing and operation steps are simplified, which greatly reduces the simulation operation threshold of the circumferential heating device and effectively improves the simulation calculation efficiency of the circumferential heating device.

[0205] In addition, under the premise of ensuring calculation accuracy and device adaptability, the present invention combines simulation technology with the comprehensive heat transfer theoretical basis of circumferential heating devices, which not only improves the efficiency of heating device design optimization, but also provides a set of fast and effective methods for the design and development of circumferential heating devices in the industry.

[0206] Based on the above invention concept, the present invention also provides a heating smoking device design device based on rapid simulation technology, which includes: a processing module, which is used to simplify and couple the radiation heat transfer formula and the convection heat transfer formula according to the physical parameters of the heat dissipation component to obtain a comprehensive heat transfer coefficient model of the heat dissipation component; a simulation module, which is used to use the ambient temperature T 0 , the total heat transfer Q of the heating device to the outer wall temperature T of the heat dissipation component w Perform temperature simulation calculation; display module, used to display the wall temperature T w The temperature simulation process is presented through a visualization system.

[0207] The present invention also provides an electronic device, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor implements the above-mentioned method for designing a heated smoking device by running the executable instructions.

[0208] It should be noted that the systems, devices or modules described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer, and the specific form of the computer can be a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email transceiver, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0209] In a typical configuration, a computer includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0210] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0211] Computer-readable media include permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, disk storage, quantum memory, graphene-based storage media or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0212] The terms and expressions used herein are for descriptive purposes only, and the present invention should not be limited to these terms and expressions. The use of these terms and expressions does not mean to exclude any equivalent features of the illustrations and descriptions (or parts thereof), and it should be recognized that various modifications that may exist should also be included in the scope of the claims. Other modifications, variations and substitutions may also exist. Accordingly, the claims should be deemed to cover all such equivalents.

[0213] Similarly, it should be pointed out that although the present invention has been described with reference to the current specific embodiments, ordinary technicians in this technical field should realize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions may be made without departing from the spirit of the present invention. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present invention, they will fall within the scope of the claims of the present invention.

Claims

1. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall, characterized in that: The calculation method specifically comprises the following steps: Step A: According to the physical parameters of the heat dissipation component, the radiation heat transfer formula and the convection heat transfer formula are simplified and coupled to obtain a comprehensive heat transfer coefficient model of the heat dissipation component; Step B: Based on the above-mentioned comprehensive heat transfer coefficient model, using the ambient temperature T0 and the total heat transfer Q of the circumferential heating device, the outer wall temperature T w Perform temperature simulation calculations; Step C: Set the wall temperature T w The temperature simulation process is presented through a visualization system.

2. The method for calculating the comprehensive heat transfer coefficient of the wall of a circumferential heating device according to claim 1, characterized in that: The step A specifically comprises: Step A1: simplifying the radiation heat transfer formula according to the physical parameters of the heat dissipation component to obtain a simplified radiation heat transfer rate; Step A2: simplifying the convection heat transfer formula according to the physical parameters of the heat dissipation component to obtain a simplified convection heat transfer rate; Step A3: coupling the simplified radiation heat transfer rate and the simplified convection heat transfer rate to obtain a comprehensive heat transfer coefficient model of the heat dissipation component; The temperature simulation calculation is a non-grid fast simulation calculation; The heating smoking device is a circumferential heating device, the heating component is a tubular heating element; the heat insulation component is a tubular heat insulation element sleeved on the outside of the tubular heating element; the heat dissipation component is a heat dissipation shell sleeved on the outside of the tubular heat insulation element.

3. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall according to claim 2, characterized in that: The step A1 specifically includes: Step A11: Set the outer wall temperature T w Take two end values ​​and at least one intermediate value in the range of 25-60°C, and substitute them into the radiation heat transfer formula to calculate the surface temperature T of each outer wall. w The corresponding radiation heat transfer rate a R1 ; Step A12: According to the temperature T of each outer wall w The corresponding radiation heat transfer rate Q R , get Q R About T w The first fitting formula of the simplified radiation heat transfer rate α is obtained R3 .

4. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall according to claim 3, characterized in that: The radiation heat transfer formula is: Among them, Q R is the radiation heat transfer heat flux, δ0 ​​is the Stefan Borchert constant [5.67*10 -8 w / (m 2 ·k 4 )], ε is the total emissivity of the material, S is the wall area of ​​the device, is the view factor, T w is the wall temperature, and T0 is the ambient temperature.

5. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall according to claim 4, characterized in that: The step A12 is specifically as follows: Step A121: Simplify the radiation heat transfer formula to: Q R =α R1 S(T w -T0) (2) Among them, α R is the radiation heat transfer coefficient, s is the wall area of ​​the device, T w is the wall temperature, T0 is the ambient temperature; Step A122: Determine the angle coefficient based on the ambient temperature T0 is 1, and substituting it into the radiation heat transfer formula, we get the following formula: Among them, α R is the radiation heat transfer coefficient, δ0 is the Stephen Borhertz constant [5.67*10 -8 w / (m 2 ·k 4 )], ε is the total emissivity of the material, T w is the wall temperature, T0 is the ambient temperature; Step A123: Set the ambient temperature T0 to 20°C, the wall temperature to 25-60°C, and the total wall emissivity to 0.2-0.8, and calculate the wall temperature T w and radiation heat transfer coefficient α R relation; Step A124: According to the wall temperature T w and radiation heat transfer coefficient α R Relationship, it is determined that the radiation heat transfer coefficient can be expressed as the product of the basic radiation heat transfer coefficient and the emissivity, and the following radiation heat transfer rate α is obtained R2 : a R2 =ε(5.0364+0.0325T w ) (4) Where ε is the total emissivity of the material, T w is the wall temperature; Step A125: According to the wall temperature T w With the radiation heat transfer rate α R2 The relationship between the total material emissivity ε and the radiation heat transfer rate α R2 The relationship between the radiation heat transfer rate α R2 The fitting is simplified to obtain the following simplified radiation heat transfer rate α R3 : a R3 =Ae (5) Where A is the wall temperature T w The relative scaling factor within a preset temperature range.

6. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall according to claim 5, characterized in that: The step A2 specifically includes: Step A21: according to the wall shapes, sizes and / or orientations of different heat dissipation components, substitute the convection heat transfer formulas to calculate the radiation heat transfer rates corresponding to the wall types; Step A22: Simplify the radiation heat transfer rate into the wall type parameter L and the outer wall temperature T w function.

7. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall according to claim 6, characterized in that: The convective heat transfer formula is: Q C =α c1 S(T w -T0) (6) Among them, Q C is the convective heat flux, α c1 is the convection heat transfer coefficient, S is the wall area of ​​the equipment, T w is the wall temperature, and T0 is the ambient temperature.

8. The method for calculating the comprehensive heat transfer coefficient of the wall surface of a circumferential heating device according to claim 6, characterized in that: The step A21 comprises: Step A211: Based on the Rayleigh number or Nusselt number formula, the relationship between the convective heat transfer coefficient and the wall temperature and size corresponding to the convective surface facing upward, the heat surface facing downward and the vertical wall is processed, and the convective heat transfer coefficient corresponding to different flat walls is obtained by substituting the convective heat transfer formula into the convective heat transfer coefficient: Among them, α P,T is the convective heat transfer coefficient of the flat wall with the hot surface facing upward, α P,B is the convective heat transfer coefficient of the flat wall with the hot surface facing downward, α P,v is the convective heat transfer coefficient of the vertical wall, T w is the wall temperature, W is the wall width, and H is the wall height; Step A212: Based on the Rayleigh number or Nusselt number formula, the relationship between the convective heat transfer coefficient and the wall temperature and size corresponding to the horizontal cylindrical wall and the spherical wall is processed, and the convective heat transfer coefficient corresponding to different curved walls is obtained by substituting the convective heat transfer coefficient into the convective heat transfer formula: Among them, α Cy is the convection heat transfer coefficient of the horizontal cylindrical wall, α S is the convection heat transfer coefficient of the spherical wall, and R is the radius of the curved surface.

9. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall according to claim 6, characterized in that: The step A22 specifically includes: Step A221: Simplify the convective heat transfer coefficient corresponding to the flat wall and the convective heat transfer coefficient corresponding to the curved wall to obtain: Among them, the coefficient B is the proportionality coefficient related to the wall type, T w is the wall temperature, and L is a size parameter related to the wall type.

10. A method for calculating the comprehensive heat transfer coefficient of a circumferential heating device wall according to claim 9, characterized in that: The comprehensive heat transfer coefficient model is: α T ＝α R3 +α C (13) Among them, α T is the comprehensive heat transfer coefficient, α R3 To simplify the radiation heat transfer rate, α C To simplify the convection heat transfer rate.

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