Solid radiation heat transfer calculation method and device for radiant heating furnace

Abstract

The present application relates to the technical field of radiant heating furnace, and particularly relates to a solid radiation heat calculation method and device for radiant heating furnace. The method establishes a symmetrical simplified model with the center line of the furnace body as the reference, takes the unit length radiation heat space along the depth direction of the furnace body as the calculation object, and constructs a solid heat transfer model containing the outer diameter of the furnace tube, the spacing and the temperature parameters of the furnace wall by combining with the grid division technology. By introducing the radiation heat correction coefficient C, the heat flux density in the radiation heat formula is corrected, and the influence of the spacing of the furnace tube on the radiation heat area is corrected. Based on the comparison between the numerical simulation and the actual working condition, the value of C is dynamically determined to ensure the robustness of the model under complex working conditions, so that the calculation result is significantly reduced compared with the traditional model. The system cooperates with the symmetrical model construction, the correction coefficient calculation and the heat transfer calculation module, and provides reliable technical support for the design and optimization of industrial furnace body through the symmetrical modeling simplification, dynamic parameter adjustment and numerical simulation verification.

Description

Technical Field

[0001] This invention relates to the field of radiant heating furnace technology, and in particular to a method and apparatus for calculating solid radiation heat transfer in a radiant heating furnace. Background Technology

[0002] Radiant heating furnaces are one of the core pieces of equipment in the petrochemical industry. They transfer heat to the materials inside the furnace tubes through the high-temperature flames and radiant heat transfer from the furnace walls, thereby raising the temperature of the materials and enabling processing. Solid-state radiant heat transfer calculations are a crucial aspect of furnace design, directly impacting furnace structure optimization, thermal efficiency improvement, and energy consumption control.

[0003] Currently, the following methods are commonly used in radiative heat transfer calculation models:

[0004] Simplified geometric assumptions: The furnace tubes are considered as infinitely long cylinders, and the effects of changes in furnace tube spacing on radiation shielding and effective heat transfer area are ignored;

[0005] Traditional formula application: Heat flux density is calculated based on the Stefan-Boltzmann law and the angle coefficient, but no correction parameters related to the furnace tube spacing are introduced;

[0006] Numerical simulation assistance: Three-dimensional modeling is performed using software such as FDS and ANSYS, but the computational complexity is high and it requires a large amount of experimental data for calibration, making it difficult to be directly applied to rapid estimation in the early stages of engineering design.

[0007] Existing models cannot accurately reflect the coupled effects of changes in parameters such as furnace wall temperature and material flow rate on heat transfer under high temperature, high pressure, and variable load conditions. This leads to conservative furnace design, such as excessively increasing the spacing between furnace tubes to avoid local overheating, resulting in energy waste or low thermal efficiency. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] This invention provides a method and apparatus for calculating solid radiation heat transfer in a radiant heating furnace, which overcomes the problem in the prior art that the calculation model for solid radiation heat transfer in a radiant heating furnace does not fully consider the influence of furnace tube spacing on radiation heat transfer, resulting in a large error in the calculation of heat flux density.

[0010] (II) Technical Solution

[0011] This invention provides a method for calculating solid radiation heat transfer in a radiant heating furnace, comprising the following steps:

[0012] Step S1, establish a symmetrical calculation model: taking the center line of the target furnace body as the reference, and utilizing the symmetry of the center plane of the target furnace body structure, the unit length of the radiative heat transfer space along the depth direction of the target furnace body is taken as the model object to establish a symmetrical simplified model.

[0013] Step S2, calculate heat flux density: Introduce a correction factor to correct the heat flux density. Add a correction factor C for radiation heat transfer to the radiation heat transfer formula. The corrected heat flux density calculation formula is q. ‘ =C·q, where q ’ The corrected heat flux density is q, and the original heat flux density is q. The value of the radiative heat transfer correction coefficient C ranges from 0.003 to 0.007, preferably 0.005.

[0014] Step S3, calculate heat transfer based on the modified model: using the symmetric model established in step S1 and the modified heat flux density calculation formula in step S2, calculate the heat flux density on the outer surface of the furnace tube, wherein the radiative heat transfer correction coefficient C is used to correct the influence of the furnace tube spacing on the radiative heat transfer area.

[0015] Preferably, the step S1 of establishing the symmetric computation model includes:

[0016] Step S11: The target furnace body is divided into grids to form a solid radiation heat transfer grid model. The solid radiation heat transfer grid model includes the furnace tube outer diameter, furnace tube spacing and furnace wall temperature parameters of the target furnace body.

[0017] Preferably, the radiative heat transfer formula in step S2 is: Where ε is the emissivity of the radiating object, σ is the Stefan-Boltzmann constant, T1 is the absolute temperature of the radiation source, T2 is the absolute temperature of the radiated object, and F is the radiation angle coefficient.

[0018] Preferably, the value of the radiation heat transfer correction coefficient C in step S2 is determined by the following method: simulating the radiation heat transfer process under different furnace tube spacing, furnace tube outer diameter and furnace wall temperature conditions based on numerical simulation software, comparing the simulation results with the actual measurement results, and determining the value of C that makes the relative error between the simulation results and the actual measurement results less than 26.7%.

[0019] Preferably, the radiation angle coefficient F is calculated based on the geometric relationship between the furnace tube spacing and the furnace tube outer diameter, combined with the symmetry of the furnace body centerline. The furnace tube spacing is the center distance between adjacent furnace tubes, and the furnace tube outer diameter is the outer diameter of the furnace tube.

[0020] On the other hand, the present invention also provides a solid radiation heat transfer device for a radiation heating furnace, including: a symmetry model construction module, a correction coefficient calculation module, and a heat transfer calculation module;

[0021] The symmetry model construction module is used to establish a gridded calculation model based on the symmetry of the furnace body's central plane. The correction coefficient calculation module dynamically adjusts the C value based on numerical simulation data. The heat transfer calculation module uses the correction formula q. ’ =C·q Output heat flux density.

[0022] Preferably, it further includes: a data acquisition module and an adaptive control module;

[0023] The data acquisition module collects furnace tube spacing, furnace wall temperature, and furnace load parameters in real time, and the adaptive control module dynamically adjusts the radiative heat transfer correction coefficient C based on the collected parameters.

[0024] Preferably, the data acquisition module includes a temperature sensor and a displacement sensor, which respectively acquire furnace wall temperature distribution data and furnace tube spacing change in real time.

[0025] (III) Beneficial Effects

[0026] This invention provides a method and apparatus for calculating solid radiation heat transfer in a radiant heating furnace. It enables the rapid generation of a high-precision radiation heat transfer calculation model by establishing a symmetrical simplified model based on the furnace centerline and dividing the heat transfer space into a grid. This reduces redundant calculations. A radiation heat transfer correction coefficient C is introduced to correct the heat flux density calculation value in the traditional radiation heat transfer formula, resolving the issue of neglecting the radiation heat transfer area due to the furnace tube spacing. The corrected formula q... ‘ =C·q controls the relative error between the calculated result and the actual measured value to 6.7%-26.7%, which is significantly lower than the error of the traditional model;

[0027] The correction coefficient calculation module dynamically determines the C value based on the comparison between numerical simulation and actual working conditions. It verifies the heat transfer effect under different furnace tube spacing, outer diameter and temperature through numerical simulation software, ensuring the robustness of the correction model under complex working conditions and ensuring that the correction coefficient is accurately matched with the specific furnace structure, thus avoiding the limitations of a single empirical value.

[0028] The system has a clear division of labor among its modules. The symmetry model construction module is responsible for structural modeling, the correction coefficient module processes dynamic parameters, and the heat transfer calculation module outputs results. The collaborative work between modules can quickly respond to changes in operating conditions and improve the system's practicality. Thus, through correction coefficient optimization, symmetry modeling simplification, dynamic parameter adjustment, and numerical simulation verification, the system achieves high efficiency, energy saving, and intelligence in furnace design, providing reliable technical support for the design and optimization of industrial furnaces. Attached Figure Description

[0029] Figure 1 This invention provides a schematic flowchart of a solid radiation heat transfer calculation method for a radiant heating furnace.

[0030] Figure 2 The diagram shows a schematic of the solid radiation heat transfer device for a radiant heating furnace according to the present invention. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "inner," "outer," "top," and "bottom" are based on the orientations or positional relationships shown in the accompanying drawings. They are intended only to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the components referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] like Figure 1 The present invention provides a method for calculating solid radiation heat transfer in a radiant heating furnace, comprising the following steps:

[0034] Step S1, establish a symmetrical calculation model: Taking the centerline of the target furnace body as the reference, and utilizing the central symmetry of the target furnace body structure (i.e., the distances between the two furnace walls and the outermost furnace tubes are equal), the unit length of the radiative heat transfer space along the depth direction of the target furnace body is used as the model object to construct a symmetrical simplified model, as follows:

[0035] The step S1, which involves establishing the symmetric computational model, includes:

[0036] Step S11: Refine the mesh of the target furnace body to form a solid radiation heat transfer mesh model containing the following key parameters:

[0037] Furnace tube outer diameter d: A fundamental parameter that directly affects the radiant heat transfer area;

[0038] Furnace tube spacing s: the center distance between adjacent furnace tubes, which significantly affects the radiation shielding effect and the effective heat transfer area;

[0039] Furnace wall temperature T_w: Furnace boundary conditions, which determine the temperature gradient for radiative heat transfer;

[0040] Furnace length L: A unit length model along the depth direction, simplifying three-dimensional heat transfer into a two-dimensional symmetric problem;

[0041] Based on the symmetry of the furnace structure, only the half-side region bounded by the centerline needs to be calculated. The heat transfer characteristics of the entire furnace are derived through the principle of mirror symmetry, reducing computational complexity and data volume.

[0042] Step S2 introduces a "radiation heat transfer correction coefficient C" based on the traditional radiation heat transfer formula to correct the influence of furnace tube spacing on the radiation heat transfer area, as follows:

[0043] Traditional radiative heat transfer formula

[0044] The original heat flux density formula is:

[0045]

[0046] In the formula: ε is the emissivity of the radiating object, σ = 5.67 × 10 -8 W / (m 2 ·K 4 ) is the Stefan-Boltzmann constant, T1 is the absolute temperature of the radiation source, T2 is the absolute temperature of the irradiated object, and F is the radiation angle coefficient, which is calculated by the furnace tube spacing s and symmetry to reflect the direction and efficiency of radiation energy transfer.

[0047] The radiation angle coefficient F is calculated based on the geometric relationship between the furnace tube spacing and the furnace tube outer diameter, combined with the symmetry of the furnace body centerline. The furnace tube spacing is the center distance between adjacent furnace tubes, and the furnace tube outer diameter is the outer diameter of the furnace tube.

[0048] The corrected heat flux density formula is:

[0049] q'=C·q

[0050] In the formula: C is the correction coefficient for radiative heat transfer, with a value ranging from 0.003 to 0.007, and a preferred value of 0.005. The physical meaning of the correction coefficient is to correct the deviation in effective heat transfer area caused by the furnace tube spacing. When the furnace tube spacing decreases, the radiative shielding effect between adjacent furnace tubes increases, and the actual effective heat transfer area is less than the theoretical value. The heat flux density calculation result needs to be adjusted by C.

[0051] The method for determining the correction coefficients, verified under multiple operating conditions using numerical simulation software, includes:

[0052] Perform radiation heat transfer simulation for each set of parameters and calculate the heat flux density on the outer surface of the furnace tube;

[0053] By comparing the simulation results with actual industrial furnace measured data, the heat flux density was inferred by measuring the surface temperature distribution of the furnace tubes using a thermocouple array.

[0054] Adjust the C value so that the relative error between the simulation result and the measured value is ≤26.7%, and finally determine the optimal range of C values.

[0055] Step S3, calculate heat transfer based on the modified model: Using the symmetric mesh model established in step S1 and the modified formula in step S2, calculate the heat flux density on the outer surface of the furnace tube. The specific process is as follows:

[0056] Multiplying the q calculated by the traditional formula by the correction factor C yields the corrected heat flux density q. ‘ The formula is:

[0057]

[0058] like Figure 2 The present invention provides a solid radiation heat transfer device for a radiant heating furnace, which is used to perform a solid radiation heat transfer calculation method for a radiant heating furnace, including: a symmetry model construction module, a correction coefficient calculation module, and a heat transfer calculation module;

[0059] This symmetric model building module is used to establish a meshed computational model based on the symmetry of the furnace body's central plane. The symmetric model's working states include:

[0060] Inputs: Furnace body structural parameters d, s, L, and boundary conditions

[0061] Output: A meshed model file containing node coordinates, material properties, and boundary conditions.

[0062] The correction factor calculation module dynamically adjusts the C value based on numerical simulation data, and the heat transfer calculation module uses the correction formula q. ‘ =C·q output heat flux density;

[0063] The solid radiation heat transfer device for the radiation heating furnace also includes: a data acquisition module and an adaptive control module;

[0064] The data acquisition module collects furnace tube spacing, furnace wall temperature and furnace load parameters in real time. The adaptive control module dynamically adjusts the radiative heat transfer correction coefficient C according to the collected parameters.

[0065] The adaptive control module dynamically adjusts the furnace tube layout based on the real-time collected furnace tube spacing parameters, so that the correction coefficient C is negatively correlated with the furnace tube spacing, in order to minimize the calculation error of radiative heat transfer.

[0066] The data acquisition module collects key parameters related to the operation of the heating furnace in real time, continuously monitors and obtains the furnace operating parameters, and transmits these raw data to the adaptive control module after preliminary processing.

[0067] The data acquisition module includes a temperature sensor and a displacement sensor, which respectively collect real-time data on furnace wall temperature distribution and furnace tube spacing changes.

[0068] The adaptive control module receives parameters transmitted from the data acquisition module, performs real-time analysis, initially determines the adjustment direction of the correction coefficient C, transmits the processed data to the symmetric model construction module, and simultaneously receives the final C value fed back by the correction coefficient calculation module, thus completing the closed-loop control of the system parameters.

[0069] The symmetric model building module receives parameters transmitted from the adaptive control module, determines the boundary conditions for model building, discretizes the furnace structure into grid cells using numerical calculation methods, builds a symmetric model that can be used for heat transfer calculation, and transmits it to the heat transfer calculation module.

[0070] The heat transfer calculation module receives the meshed model from the symmetric model construction module, calls the heat transfer calculation formula, inputs the pre-correction heat flux density q obtained from historical data, and the initial value of C provided by the adaptive control module, and calculates the post-correction heat flux density q. ’ The results are then transmitted to the correction coefficient calculation module.

[0071] The correction factor calculation module receives q from the heat transfer calculation module. ’ The data is compared with the standard heat flux density data obtained through numerical simulation, and the final correction coefficient C is calculated and fed back to the adaptive control module for parameter adjustment in the next round of heat transfer calculation.

[0072] It is understood that the various embodiments mentioned above in this invention can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this invention will not elaborate further.

[0073] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0074] This invention provides a method and apparatus for calculating solid radiation heat transfer in a radiant heating furnace. By establishing a symmetrical simplified model based on the furnace centerline and dividing the heat transfer space into a grid, a high-precision radiation heat transfer calculation model can be quickly generated, reducing redundant calculations. A radiation heat transfer correction coefficient C is introduced to correct the calculated heat flux density value in the traditional radiation heat transfer formula, solving the problem of neglecting the radiation heat transfer area due to the furnace tube spacing. The corrected formula q... ‘ =C·q controls the relative error between the calculated result and the actual measured value to 6.7%-26.7%, which is significantly lower than the error of the traditional model;

[0075] The correction coefficient calculation module dynamically determines the C value based on the comparison between numerical simulation and actual working conditions. It verifies the heat transfer effect under different furnace tube spacing, outer diameter and temperature through numerical simulation software, ensuring the robustness of the correction model under complex working conditions and ensuring that the correction coefficient is accurately matched with the specific furnace structure, thus avoiding the limitations of a single empirical value.

[0076] The system has a clear division of labor among its modules. The symmetry model construction module is responsible for structural modeling, the correction coefficient module processes dynamic parameters, and the heat transfer calculation module outputs results. The collaborative work between modules can quickly respond to changes in operating conditions and improve the system's practicality. Thus, through correction coefficient optimization, symmetry modeling simplification, dynamic parameter adjustment, and numerical simulation verification, the system achieves high efficiency, energy saving, and intelligence in furnace design, providing reliable technical support for the design and optimization of industrial furnaces.

[0077] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for calculating solid radiation heat transfer in a radiant heating furnace, characterized in that, Includes the following steps: Step S1, establish a symmetrical calculation model: taking the center line of the target furnace body as the reference, and utilizing the symmetry of the center plane of the target furnace body structure, the unit length of the radiative heat transfer space along the depth direction of the target furnace body is taken as the model object to establish a symmetrical simplified model. Step S2, calculate heat flux density: Introduce a correction factor to correct the heat flux density. Add a correction factor C for radiation heat transfer to the radiation heat transfer formula. The corrected heat flux density calculation formula is q. ‘ =C·q, where q ’ The corrected heat flux density is q, and the original heat flux density is q. The value of the radiative heat transfer correction coefficient C ranges from 0.003 to 0.007, preferably 0.

005. Step S3, calculate heat transfer based on the modified model: using the symmetric model established in step S1 and the modified heat flux density calculation formula in step S2, calculate the heat flux density on the outer surface of the furnace tube, wherein the radiative heat transfer correction coefficient C is used to correct the influence of the furnace tube spacing on the radiative heat transfer area.

2. The method for calculating solid radiation heat transfer in a radiant heating furnace according to claim 1, characterized in that, The step S1 of establishing the symmetric computation model includes: Step S11: The target furnace body is divided into grids to form a solid radiation heat transfer grid model. The solid radiation heat transfer grid model includes the furnace tube outer diameter, furnace tube spacing and furnace wall temperature parameters of the target furnace body.

3. The method for calculating solid radiation heat transfer in a radiant heating furnace according to claim 1, characterized in that, The radiative heat transfer formula in step S2 is: Where ε is the emissivity of the radiating object, σ is the Stefan-Boltzmann constant, T1 is the absolute temperature of the radiation source, T2 is the absolute temperature of the radiated object, and F is the radiation angle coefficient.

4. The method for calculating solid radiation heat transfer in a radiant heating furnace according to claim 1, characterized in that, The value of the radiation heat transfer correction coefficient C in step S2 is determined in the following way: the radiation heat transfer process under different furnace tube spacing, furnace tube outer diameter and furnace wall temperature conditions is simulated based on numerical simulation software, the simulation results are compared with the actual measurement results, and the value of C that makes the relative error between the simulation results and the actual measurement results less than 26.7% is determined.

5. The method for calculating solid radiation heat transfer in a radiant heating furnace according to claim 3, characterized in that, The radiation angle coefficient F is calculated based on the geometric relationship between the furnace tube spacing and the furnace tube outer diameter, combined with the symmetry of the furnace body centerline. The furnace tube spacing is the center distance between adjacent furnace tubes, and the furnace tube outer diameter is the outer diameter of the furnace tube.

6. A solid-state radiation heat transfer device for a radiant heating furnace, used to perform the solid-state radiation heat transfer calculation method for a radiant heating furnace as described in claims 1-4, characterized in that, include: Symmetric model construction module, correction coefficient calculation module, and heat transfer calculation module; The symmetry model construction module is used to establish a gridded calculation model based on the symmetry of the furnace body's central plane. The correction coefficient calculation module dynamically adjusts the C value based on numerical simulation data. The heat transfer calculation module uses the correction formula q. ’ =C·q Output heat flux density.

7. The solid radiation heat transfer device for a radiant heating furnace according to claim 6, characterized in that, Also includes: Data acquisition module and adaptive control module; The data acquisition module collects furnace wall temperature and furnace load parameters in real time, and the adaptive control module dynamically adjusts the radiative heat transfer correction coefficient C according to the collected parameters.

8. The solid radiation heat transfer device for a radiant heating furnace according to claim 7, characterized in that, The data acquisition module includes a temperature sensor and a displacement sensor, which respectively acquire furnace wall temperature distribution data and furnace tube spacing changes in real time.

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