Recuperator design apparatus, design method, program, and recuperator

Abstract

To improve heat exchange efficiency. [Solution] The recuperator design apparatus is a design apparatus for a radiant tube type heating apparatus, in which a recuperator is provided in the radiant tube, mediating heat exchange between exhaust gas flowing through the radiant tube after burning fuel and combustion air used for burning the fuel, and comprises an acquisition unit that acquires heat exchange efficiency information relating to the efficiency of heat exchange between the exhaust gas and the combustion air, and a determination unit that determines the shape of the partition wall between the exhaust gas and the combustion air based on the calculation result by topology optimization using the heat exchange efficiency information.

Description

Technical Field

[0001] The present disclosure relates to a recuperator design device, a design method, a program, and a recuperator.

Background Art

[0002] A radiant tube type heating device used in a heating furnace or the like includes, for example, a radiant tube and a recuperator provided in the radiant tube. The recuperator is a heat exchanger as disclosed in Patent Document 1, for example, and mediates heat exchange between exhaust gas flowing through the radiant tube after fuel combustion and combustion air used for fuel combustion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a radiant tube, it is desirable to recover more thermal energy contained in exhaust gas for use in fuel combustion and supply it to combustion air. However, in conventional recuperators, since heat exchange is performed with a partition wall to prevent exhaust gas from mixing into the combustion air, the heat exchange efficiency has not been sufficiently improved.

[0005] In addition, in heat exchangers for radiant tube applications, it is necessary to suppress the internal pressure of the tubes as much as possible to prevent the leakage of exhaust gas from inside the tubes in the event of tube failure. Generally, increasing the heat transfer area increases the heat exchange efficiency, but increasing the contact area between the exhaust gas and combustion air and the partition wall increases friction in the flow, leading to an increase in the driving pressure. Therefore, designing radiant tubes is extremely difficult because it requires considering the conflicting properties of ensuring the necessary heat exchange efficiency while suppressing pressure loss.

[0006] This disclosure has been made in consideration of these circumstances, and aims to provide a design apparatus, design method, program, and recuperator capable of improving heat exchange efficiency. [Means for solving the problem]

[0007] One aspect of the present disclosure is a design apparatus for a radiant tube type heating device, comprising a radiant tube and a recuperator provided in the radiant tube, wherein the recuperator mediates heat exchange between exhaust gas flowing through the radiant tube after burning fuel and combustion air used for burning the fuel, the design apparatus comprising: an acquisition unit for acquiring heat exchange efficiency information relating to the efficiency of heat exchange between the exhaust gas and the combustion air; and a determination unit for determining the shape of a partition wall between the exhaust gas and the combustion air based on calculation results obtained by topology optimization using the heat exchange efficiency information.

[0008] One aspect of the present disclosure is a design apparatus for a radiant tube type heating device, comprising a radiant tube and a recuperator provided in the radiant tube, wherein the recuperator mediates heat exchange between exhaust gas flowing through the radiant tube after burning fuel and combustion air used for burning the fuel, and is a design method for a recuperator in which a computer acquires heat exchange efficiency information relating to the efficiency of heat exchange between the exhaust gas and the combustion air, and determines the shape of the partition wall between the exhaust gas and the combustion air based on the calculation result by topology optimization using the heat exchange efficiency information.

[0009] One aspect of the present disclosure is a design apparatus for a radiant tube heating apparatus, comprising a radiant tube and a recuperator provided in the radiant tube, wherein the recuperator mediates heat exchange between exhaust gas flowing through the radiant tube after burning fuel and combustion air used for burning the fuel, and is a program that causes a computer to acquire heat exchange efficiency information relating to the efficiency of heat exchange between the exhaust gas and the combustion air, and to determine the shape of the partition wall between the exhaust gas and the combustion air based on the calculation result of topology optimization using the heat exchange efficiency information.

[0010] One aspect of the present disclosure is a recuperator for a radiant tube heating device, comprising a radiant tube and a recuperator provided on the radiant tube, wherein the recuperator mediates heat exchange between exhaust gas flowing through the radiant tube after the combustion of fuel and combustion air used for the combustion of the fuel, and the recuperator is designed using the aforementioned recuperator design device. [Effects of the Invention]

[0011] According to the design apparatus, design method, program, and recuperator described herein, heat exchange efficiency can be increased. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows an example of the configuration of the radiant tube type heating device 1 according to the first embodiment. [Figure 2] This is a perspective view of Recuperator 20. [Figure 3] This figure shows an example of gas flow inside and outside the recuperator 20. [Figure 4] This figure shows an example of the configuration of a design device 100 for designing the shape of a recuperator 20. [Figure 5] This is a flowchart showing an example of the processing performed by the control unit 140. [Figure 6] This graph shows the relationship between the objective function J and the spatial distribution of the material. [Figure 7] This diagram visualizes the processing flow in the radiant tube type heating device 1 of the first embodiment. [Figure 8] This is a schematic perspective view of the recuperator 60 of the second embodiment. [Figure 9] This is a schematic perspective view of the recuperator 60 of the second embodiment. [Figure 10] This is a diagram showing a magnified view of a portion of the inside of the recuperator 60. [Modes for carrying out the invention]

[0013] The design apparatus, design method, program, and recuperator of the embodiment will be described below with reference to the drawings.

[0014] [First Embodiment] Figure 1 shows an example of the configuration of a radiant tube type heating device 1 according to the first embodiment. The radiant tube type heating device 1 according to the first embodiment includes, for example, a radiant tube 10, a recuperator 20, a burner device 30, and a connecting part 50.

[0015] The radiant tube 10 is formed of, for example, cast iron or heat-resistant steel. The radiant tube 10 has a U shape when viewed from the side. The radiant tube 10 includes, for example, a first straight portion 11, a second straight portion 12, and a curved portion 13. The first straight portion 11, the second straight portion 12, and the curved portion 13 are all tubular bodies and have hollow portions.

[0016] The first straight portion 11 and the second straight portion 12 are arranged parallel to each other, for example, and penetrate the furnace wall in the vertical direction. The hollow portions of the first straight portion 11, the curved portion 13, and the second straight portion 12 communicate with each other in this order. The radiant tube 10 may be formed as an integral body, or may be formed in a U shape by joining two straight tubes and a curved tube by means of a joint or welding. The radiant tube 10 may have a shape other than the U shape. The radiant tube 10 may be, for example, a W shape or an I shape (linear shape).

[0017] The recuperator 20 is a heat exchanger that mediates heat exchange between the exhaust gas flowing through the radiant tube 10 after burning the fuel and the combustion air used for burning the fuel. The exhaust gas includes combustion exhaust gas CG and discharged exhaust gas EG. The exhaust gas flows through the radiant tube 10 after burning the fuel discharged by the burner device 30. The combustion air includes pre-heat-exchange combustion air CA and post-heat-exchange combustion air PA. The combustion air, particularly the post-heat-exchange combustion air PA, is supplied to the burner device 30. The post-heat-exchange combustion air PA is used for burning the fuel discharged by the burner device 30.

[0018] The recuperator 20 is formed by, for example, modeling methods such as a machining center, a 3D (3-Dimension) printer, or a casting method. The recuperator 20 is inserted into the inside of the radiant tube 10 from an end on the side opposite to the side where the curved portion 13 in the second straight portion 12 of the radiant tube 10 is connected. The modeling includes, for example, construction and processing, and the processing includes, for example, cutting, drilling, and grooving. The recuperator 20 may be manufactured by a processing device that processes materials such as a machining center or a modeling device that models products such as a 3D printer.

[0019] FIG. 2 is a perspective view of the recuperator 20. The recuperator 20 has at least a flow path structure 23 for performing heat exchange while distinguishing the combustion exhaust gas CG and the pre-combustion air CA. For example, the flow path structure 23 is constituted by a partition wall 22 (also referred to as a first partition wall 22). For example, the combustion exhaust gas CG flows inside the radiant tube 10 and outside the recuperator 20, and the pre-combustion air CA is introduced inside the recuperator 20.

[0020] A plurality of, for example, ring-shaped ridges are provided on the outside of the recuperator 20 at intervals in the longitudinal direction. A narrow gap is formed between the ridges. By forming these gaps, the surface area of the outer periphery of the recuperator 20 is increased. The combustion exhaust gas CG flows along the outer surface of the recuperator 20. The pre-combustion air CA flows along the inner surface of the recuperator 20. By increasing the surface area of the outer periphery of the recuperator 20, the area of the recuperator 20 (partition wall 22) that mediates heat exchange between the combustion exhaust gas CG and the pre-combustion air CA becomes larger, and the heat exchange efficiency is accordingly increased.

[0021] FIG. 3 is a diagram showing an example of the gas flow inside and outside the recuperator 20. The combustion exhaust gas CG and the pre-combustion air CA exchange heat mainly through the outer periphery of the recuperator 20 and the partition wall 22. The combustion exhaust gas CG after heat exchange becomes the discharged exhaust gas EG and is discharged to the outside of the radiant tube type heating device 1. The pre-combustion air CA inside the recuperator 20 is heated to become the post-heat exchange combustion air PA and is supplied to the burner device 30 through the connection portion 50. The flow path through which the pre-combustion air CA flows and the flow path through which the post-heat exchange combustion air PA flows are partitioned by, for example, a cylindrical auxiliary partition wall 24 (also referred to as a second partition wall 24). The installation of the auxiliary partition wall 24 is optional. The shape of the auxiliary partition wall 24 is not limited as long as it separates the pre-combustion air CA and the post-heat exchange combustion air PA.

[0022] The burner device 30 includes, for example, an air inlet 31, a fuel inlet 32, and a burner unit 33. The air inlet 31 introduces post-heat exchange combustion air PA supplied by the connection 50 and supplies it to the burner unit 33. The fuel inlet 32 ​​supplies combustion fuel to the burner unit 33. The burner unit 33 burns the supplied post-heat exchange combustion air PA and fuel to heat the air inside the radiant tube 10.

[0023] The connection section 50 includes, for example, an outside air inlet 51, a combustion air supply port 52, and an exhaust port 53. The outside air inlet 51 is the inlet for combustion air (pre-heat exchange combustion air CA) introduced from outside the radiant tube heating device 1 into the recuperator 20. The combustion air supply port 52 is the supply port for post-heat exchange combustion air PA supplied from the recuperator 20 to the burner device 30. The exhaust port 53 is the outlet for discharging the exhaust gas EG, which has undergone heat exchange inside the radiant tube 10, to the outside of the radiant tube heating device 1.

[0024] Inside the radiant tube 10, heat exchange occurs between the exhaust gas and the combustion gas by the recuperator 20. It is desirable that the recuperator 20 perform heat exchange with a high heat exchange efficiency. The heat exchange efficiency is affected, for example, by the shape of the partition walls 22 of the recuperator 20. The heat exchange efficiency is related, for example, to the pressure loss inside the radiant tube 10 and the temperature of the exhaust gas. Therefore, the shape of the recuperator 20 that increases the heat exchange efficiency, in particular the shape of the partition walls 22 that constitute the flow path structure 23, is designed using the design device 100.

[0025] Next, a design apparatus for designing the shape of the recuperator 20 will be described. Figure 4 shows an example of the configuration of the design apparatus 100 for designing the shape of the recuperator 20. The design apparatus 100 includes, for example, an input interface 110, a display 120, a storage unit 130, and a control unit 140.

[0026] The input interface 110 is an input device into which the operator inputs various types of information. The input interface 110 can be implemented by, for example, a mouse, keyboard, touch panel, trackball, switch, button, joystick, camera, infrared sensor, microphone, etc. The input interface 110 may also be implemented by a display device (e.g., a tablet terminal) that can communicate wirelessly with the design device 100.

[0027] The display 120 displays various types of information. The display may be, for example, a liquid crystal display, a CRT (Cathode Ray Tube), or an organic EL (Electroluminescence) display. The design device 100 may also include, in place of or in addition to, the display 120, output devices other than the display 120, such as a speaker for outputting sound or a printer for outputting print information.

[0028] The storage unit 130 is implemented by, for example, semiconductor memory elements such as RAM and flash memory, or non-transient storage media such as hard disks and optical discs. These non-transient storage media may also be implemented by other storage devices connected via a communication network, such as NAS (Network Attached Storage) or external storage server devices. The storage unit 130 may also include non-transient storage media such as ROM (Read Only Memory) and registers.

[0029] The control unit 140 includes, for example, an acquisition unit 150 and a determination unit 160. The acquisition unit 150 includes, for example, an initial shape information acquisition unit 151 and an efficiency information acquisition unit 152. The determination unit 160 includes, for example, a calculation unit 161, a constraint unit 162, and a determination unit 163. The control unit 140 realizes these functions, for example, by a hardware processor (computer) executing a program stored in the storage unit 130 (storage circuit).

[0030] Hardware processors are implemented by hardware that includes circuitry components such as CPUs (Central Processing Units), GPUs (Graphics Processing Units), LSIs (Large Scale Integrations), Application Specific Integrated Circuits (ASICs), programmable logic devices (e.g., Simple Programmable Logic Devices (SPLDs) or Complex Programmable Logic Devices (CPLDs)), and Field Programmable Gate Arrays (FPGAs).

[0031] The acquisition unit 150 acquires heat exchange efficiency information relating to the efficiency of heat exchange between the combustion exhaust gas and the combustion air. The initial shape information acquisition unit 151 in the acquisition unit 150 includes initial shape information relating to the initial shape of the partition wall 22. The initial shape information may be stored in, for example, the storage unit 130, or it may be provided from a server on the cloud via a communication device or the like.

[0032] The efficiency information acquisition unit 152 calculates and acquires pressure loss information and temperature information regarding the temperature of the combustion exhaust gas CG as heat exchange efficiency information. Pressure loss information and temperature information are, for example, predetermined target values ​​for pressure loss and outlet temperature.

[0033] Pressure loss information and temperature information may be other types of information. The outlet temperature is, for example, the temperature of the exhaust gas EG discharged from the exhaust port 53. The temperature information may be, for example, target values ​​for temperatures other than the outlet temperature, such as target values ​​for the temperature difference between the combustion exhaust gas CG and the exhaust gas EG, or target values ​​for the temperature of the pre-heat exchange combustion air CA and post-heat exchange combustion air PA.

[0034] The efficiency information acquisition unit 152 generates and acquires an objective function based on the acquired pressure information and temperature information. The objective function J is expressed by the following equation (1), for example, using the pressure loss variable PE, which is a variable related to pressure loss, and the outlet temperature variable ET, which is a variable related to the outlet temperature of the exhaust gas EG. J = -PE-ET ···(1)

[0035] The determination unit 160 determines the shape of the partition wall between the exhaust gas and the combustion air based on the calculation results from topology optimization, including the optimization of the lattice structure using heat exchange efficiency information. The calculation unit 161 in the determination unit 160 performs a simulation based on the initial shape of the partition wall 22 and the objective function to evaluate the performance of the recuperator 20.

[0036] The calculation unit 161 performs a sensitivity analysis simulation on the objective function of the spatial material distribution of the partition wall 22 based on the performance evaluation results. The calculation unit 161 updates the spatial material distribution based on the sensitivity analysis results from the sensitivity analysis simulation. The calculation unit 161 repeatedly performs performance evaluation and updates the spatial material distribution to perform calculations by topology optimization, including optimization of the lattice structure. The spatial material distribution is a numerical function that represents the physical existence state within the design domain. This function may indicate the presence or absence of a structure, the material properties of a structure, the distance to the interface of a structure, or the design variables of the lattice structure.

[0037] The restraining unit 162 sets predetermined restraining conditions with respect to the recuperator 20. When determining the final shape of the recuperator, the restraining unit 162 sets, as a restraining condition, a characteristic that should be given to the recuperator 20 when determining the shape of the partition wall 22, for example, restraining the weight of a specific part to be within a specified range. The specific part of the recuperator 20 may be the entire recuperator 20 or a part of it, and may be, for example, the weight of the partition wall 22 of the recuperator 20. The characteristics to be given to the recuperator 20 do not have to be specified by the weight of a specific part, but for example, by the pressure loss of a specific part, or by the outlet temperature of the combustion exhaust gas CG and the combustion air PA after heat exchange, or by the thickness of the member that forms the fluid partition, the surface area to be heat exchanged, the width of the passage through which the combustion air escapes, the number of branches in the passage, the total length of the passage, the internal stress generated due to the temperature difference generated during heat exchange, the quadratic coefficient of the area of ​​the plane perpendicular to the longitudinal direction of the heat exchanger, the residence time for the combustion air to be heat exchanged, the heat transfer coefficient of the heat exchanged surface, the curvature entropy of the entire heat exchanger, or by the separation of the exhaust gas passage and the combustion air passage by the partition, or by the material continuity with the member in contact with the recuperator.

[0038] Here, the weight of a specific part of the recuperator 20 is defined as the total weight of the recuperator 20. The specified value may be stored in the storage unit 130 as a predetermined numerical value, for example, or it may be output by the input interface 110 in response to user input.

[0039] The constraint unit 162 ensures that, if the weight of the recuperator 20 is less than or equal to a specified value, a first penalty is applied to the objective function used for, for example, convergence condition determination or shape updating. The first penalty may be, for example, a large value penalty added to the objective function. The objective function J, taking into account the first penalty FP, is expressed, for example, by equation (2). J = -PE - ET + FP ... (2) The first penalty may be any other penalty relating to the objective function.

[0040] The constraint unit 162, in determining the final shape of the recuperator, sets constraint conditions such that the shape of the partition wall 22 in the recuperator 20 does not exceed the manufacturing performance range (processing performance range, molding performance range) of the machining center or 3D printer (hereinafter referred to as 3D printer, etc.) that fabricates the recuperator 20. The range that does not exceed the manufacturing performance range of the machining center or 3D printer may be set, for example, based on the manufacturing performance (processing performance, molding performance) of the machining center or 3D printer, such as the width of the flow channels formed in the recuperator, the curvature of the curved portion in the curved shape, the wall thickness of a specific part, the volume, surface area, and the amount of overhang.

[0041] The constraint unit 162, when determining the shape of the partition wall 22 in the recuperator 20, ensures that a second penalty is applied to the objective function used for convergence condition determination and shape update if the shape of the partition wall 22 exceeds the manufacturing performance range of the 3D printer. The second penalty may be, for example, a penalty that increases the objective function to the same extent as the first penalty. The second penalty may be heavier or lighter than the first penalty. The second penalty may also be other penalties related to the objective function.

[0042] The determination unit 163 determines whether or not the convergence conditions are met. If the determination unit 163 determines that the convergence conditions are met, the decision unit 160 determines the shape of the recuperator 20 (partition wall 22) based on, for example, the material spatial distribution updated by the calculation unit 161. The convergence conditions may be determined as appropriate. For example, the convergence conditions are determined when the difference in material updates before and after updating the material spatial distribution, for example, the difference in the thickness of the partition wall 22, falls below a certain value. Whether or not the convergence conditions are met may also be determined by other conditions, for example, based on the update of the material spatial distribution, based on the objective function, or using variables used in the objective function. The convergence conditions are stored in, for example, the storage unit 130.

[0043] Next, the processing in the control unit 140 of the design device 100 will be explained. Figure 5 is a flowchart showing an example of the processing in the control unit 140. First, in the control unit 140, the initial shape information acquisition unit 151 in the acquisition unit 150 reads and acquires the initial shape information of the recuperator 20 stored in the storage unit 130 (step S101).

[0044] Next, the efficiency information acquisition unit 152 acquires pressure loss information and temperature information. The pressure loss information and temperature information may be stored in the storage unit 130, for example, or output by the input interface 110 in response to user input. Based on the acquired pressure loss information and temperature information, the efficiency information acquisition unit 152 generates and acquires an objective function (step S103).

[0045] Next, the calculation unit 161 performs a performance evaluation by simulation using the initial shape information of the recuperator 20 acquired by the initial shape information acquisition unit 151 and the objective function acquired by the efficiency information acquisition unit 152 (step S105). Subsequently, the constraint unit 162 determines whether the weight of the recuperator 20 is below a specified value (step S107).

[0046] If the constraint unit 162 determines that the weight of the recuperator 20 is not less than or equal to a specified value, it applies a first penalty to the objective function (step S109). If the constraint unit 162 determines that the weight of the recuperator 20 is not less than or equal to a specified value, it skips the process in step S109 and proceeds directly to step S111.

[0047] Next, the constraint unit 162 determines whether the shape of the recuperator 20 exceeds the manufacturing capabilities of a 3D printer or the like (step S111). If the constraint unit 162 determines that the shape of the recuperator 20 exceeds the manufacturing capabilities of a 3D printer or the like, it applies a second penalty to the objective function (step S113). If the constraint unit 162 determines that the shape of the recuperator 20 does not exceed the manufacturing capabilities of a 3D printer or the like, it skips the process in step S113 and proceeds directly to step S115.

[0048] Next, the determination unit 163 determines whether or not the convergence conditions are met (step S115). If it is determined that the convergence conditions are not met, the calculation unit 161 generates the material spatial distribution at the partition wall 22 of the recuperator 20 (step S117). The material spatial distribution is updated, for example, in a direction that reduces the ratio (gradient) of the objective function to the material spatial distribution.

[0049] Next, the calculation unit 161 performs a sensitivity analysis by simulating the sensitivity distribution of the generated material spatial distribution. Based on the sensitivity analysis obtained from the sensitivity distribution simulation, the calculation unit 161 updates the material spatial distribution in the partition wall 22 of the recuperator 20 (step S119).

[0050] Figure 6 is a graph showing the relationship between the objective function J and the spatial distribution of the material. The objective function J fluctuates up and down in accordance with the changes in the spatial distribution of the material. For example, the ratio (slope) of the objective function to the spatial distribution of the material becomes smaller in the first region R1 and the third region R3, and larger in the second region R2. When this relationship exists, the calculation unit 161 updates the spatial distribution of the material, for example, in the processes in the first region R1 and the third region R3.

[0051] After updating the material spatial distribution, the calculation unit 161 returns to step S105 and performs a performance evaluation. In step S115, if the determination unit 163 determines that the convergence conditions are met, it determines the shape of the generated recuperator 20 as the final shape (step S121). Thus, the control unit 140 completes the process shown in Figure 5.

[0052] Next, the processing flow in the radiant tube heating device 1 of the first embodiment will be conceptually explained. Figure 7 is a diagram visualizing the processing flow in the radiant tube heating device 1 of the first embodiment. In the radiant tube heating device 1, first, the initial shape and objective function of the recuperator 20 are obtained, and performance evaluation is performed by simulation as the first process CL1.

[0053] Next, as the second process CL2, a sensitivity analysis simulation is performed on the performance of the spatial material distribution. Subsequently, as the third process CL3, a convergence determination is made. If the convergence determination is not met in the third process CL3, as the fourth process CL4, the material spatial distribution is updated based on the sensitivity analysis based on the sensitivity analysis simulation, and the process moves to the first process CL1, continuing the same process with the shape of the recuperator 20 corresponding to the material spatial distribution updated in the fourth process. If the convergence determination is met in the third process CL3, the final shape of the recuperator 20 is determined to be the shape corresponding to the material spatial distribution updated in the previous fourth process.

[0054] In the radiant tube heating device 1 of the first embodiment, the shape of the partition wall 22 of the recuperator 20 is designed by the design device 100. This allows for reduced fluid driving force while promoting heat transfer in the radiant tube 10. As a result, pressure loss within the radiant tube 10 can be reduced, and the outlet temperature of the exhaust gas EG can be reduced, thereby improving heat exchange efficiency. Furthermore, the recuperator 20 can be made lighter.

[0055] In the first embodiment described above, the objective function is generated using coefficients based on pressure loss and temperature, but it may also be generated using coefficients based on other conditions. The objective function may be generated using variables based on, for example, the heat transfer coefficient, the thickness, volume, surface area, and overhang of a specific part of the recuperator 20. Alternatively, it may be defined by the thickness of the fluid partition members, the heat exchange surface area, the width of the passage through which the combustion air escapes, the number of branches in the passage, the total length of the passage, the internal stress generated due to the temperature difference generated during heat exchange, the quadratic coefficient of the area of ​​a surface perpendicular to the longitudinal direction of the heat exchanger, the residence time for the combustion air to undergo heat exchange, the heat transfer coefficient of the heat exchange surface, the curvature entropy of the entire heat exchanger, the partitioning between the exhaust gas passage and the combustion air passage by the partition, or by the material continuity with the member in contact with the recuperator. Some of these variables may be used in combination.

[0056] The calculation unit 161 may, for example, weight variables such as the pressure loss variable PE or the outlet temperature variable ET when setting the objective function, or it may use the ratio of the pressure loss variable PE and the outlet temperature variable ET, or the numerator and denominator of the ratio may each be the product of multiple objective variables. Equation (3) is an equation for calculating the objective function J' with the weighting coefficient w of the outlet temperature variable ET added. The weighting coefficients to be assigned to the variables may be set based on appropriate conditions. J'=-PE-wET ···(3) Equation (4) is the formula for calculating the objective function J'' based on the proportion of the dependent variable. J'' = -PE / ET ···(4)

[0057] In the first embodiment described above, the constraint unit 162 may perform other processing if the constraint conditions are not met. For example, the constraint unit 162 may impose a large penalty on the objective function used for convergence condition determination or shape update if the constraint conditions are not met.

[0058] [Second Embodiment] Next, a second embodiment will be described. The radiant tube heating device of the second embodiment differs from the first embodiment mainly in the structure of the recuperator, specifically in the partitions that constitute the flow path structure 80. The radiant tube heating device of the second embodiment will be described below, focusing on the differences from the first embodiment.

[0059] Figure 8 is a schematic perspective view of the recuperator 60 of the second embodiment. Figure 9 is a schematic perspective view of the recuperator 60 of the second embodiment. The recuperator 60 of the second embodiment has a cylindrical shape. The external shape of the recuperator 60 of the second embodiment may be other than cylindrical, for example, it may have the same shape as the recuperator 20 of the first embodiment. As shown in Figures 8 and 9, numerous exhaust gas flow holes 64 are formed on the outer circumferential surface 61, top surface 62, and bottom surface 63 of the recuperator 60. As shown in Figure 8, multiple exhaust gas flow paths 65 connecting the exhaust gas flow holes 64 are formed inside the recuperator 60.

[0060] A combustion air inlet 66 and a combustion air outlet 67 are formed at positions on the bottom surface 63 of the recuperator 60, avoiding the location where the exhaust gas flow hole 64 is formed. The combustion air inlet 66 communicates with the outside air inlet 51 of the connection part 50 (see Figure 4) described in the first embodiment, via the space between the inside of the radiant tube 10 and the outside of the recuperator 60. The combustion air outlet 67 communicates with the combustion air supply port 52 of the connection part 50.

[0061] Inside the recuperator 60, a combustion air passage 68 is formed, connecting the combustion air inlet 66 and the combustion air outlet 67. In Figure 8, the combustion air passage 68 is shown with a dashed line in the vicinity of the combustion air inlet 66 and the combustion air outlet 67, but it is formed over a wide area inside the recuperator 60. The combustion air passage 68 is formed in a position that avoids the exhaust gas passage 65, and the exhaust gas passage 65 and the combustion air passage are formed independently of each other.

[0062] Figure 10 is a magnified view of a portion of the inside of the recuperator 60. Inside the recuperator 60, the exhaust gas passage 65 and the combustion air passage 68 are intertwined and separated by a partition wall 69. Throughout the entire inside of the recuperator 60, the exhaust gas passage 65, the combustion air passage 68, and the partition wall 69 are formed as shown in Figure 10.

[0063] The design of the recuperator 60 in the second embodiment is performed by the design device 100 using the same procedure as in the first embodiment, but objective functions and constraints for topology optimization, including optimization of the lattice structure, can be set as appropriate. The variables for setting the objective function and constraints are common, and either variable may be used for the objective function or for the constraints.

[0064] Examples of variables used in the objective function and constraints include the following. The objective function and constraints may be generated using a combination of the following variables. 1. Thickness of the component that forms the fluid partition (partition 69) 2. Pressure loss due to exhaust gas passing between the radiant tube 10 and the heat exchanger of the recuperator 60. 3. Surface area where heat is exchanged between exhaust gas and combustion air. 4. Width of the passage through which the airflow (exhaust gas, combustion air) escapes. 5. The angle of the gas passage (either or both of the exhaust gas passage 65 or the combustion air passage 68, hereinafter the same) through which the airflow (exhaust gas, combustion air) in the axial direction escapes. 6. Number of branches in the gas flow path 7. Total length of the gas flow path 8. Internal stress generated due to temperature difference during heat exchange 9. Weight of Recuperator 60 10. The quadratic modulus of the area of ​​the plane perpendicular to the longitudinal direction of the recuperator 60. 11. Residence time required for heat exchange between exhaust gas and combustion air. 12. Heat transfer coefficient of the surface where exhaust gas and combustion air exchange heat. 13. Curvature entropy of the entire recuperator 60 14. Heat exchange efficiency of recuperator 60 15. Exhaust gas temperature (exhaust gas outlet temperature) discharged from recuperator 60 16. Air temperature after heat exchange between exhaust gas and combustion air (either the temperature of the exhaust gas or the combustion air, or both). 17. Heat transfer (including some or all of heat conduction, radiation, and heat transfer) from the exhaust gas region (exhaust gas passage 65) to the combustion air region (combustion air passage 68).

[0065] Among the variables mentioned above, variables such as wall thickness, surface area, width, and angle may differ depending on their respective positions. In such cases, representative values ​​such as the mean or median of each variable, or the maximum or minimum values, may be used. Curvature entropy is a parameter that expresses the complexity of the structure. Curvature entropy is calculated using elements such as curvature, curve length, curvature function, and total curve length. When using curvature entropy as a convergence condition, it may be set to, for example, 0.135.

[0066] A program for realizing the functions of any component in any of the devices described above may be recorded on a computer-readable recording medium, and that program may be loaded into a computer system and executed. Here, "computer system" includes the operating system and hardware such as peripheral devices.

[0067] Furthermore, the above program may be transmitted from a computer system that stores the program in a memory device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" used to transmit the program refers to a medium that has the function of transmitting information, such as a network like the Internet or a communication line like a telephone line.

[0068] The above program may be intended to implement some of the functions described above. The above program may also be a so-called differential file, capable of implementing the aforementioned functions in combination with programs already recorded in the computer system. A differential file may also be called a differential program.

[0069] While embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include designs and other elements that do not depart from the gist of this disclosure. [Explanation of symbols]

[0070] 1. Radiant tube heating device 10 Radiant Tubes 11 1st straight section 12 2nd straight section 13 Curved section 20,60 Recuperators 23.80 Flow channel structure 22,69 Bulkhead 24 Auxiliary bulkhead 30 Burner device 31 Air intake 32 Fuel introduction part 33 Burner section 40 High-emission materials 41 Center axis 42 Board part 50 Connection part 51 Outside air intake 52 Combustion air supply port 53 Exhaust vent 61 Outer surface 62 Top surface 63 Bottom 64 Exhaust gas flow holes 65 Exhaust gas flow path 66 Combustion air inlet 67 Combustion air exhaust port 68 Combustion air passage 100 Design equipment 110 Input Interfaces 120 displays 130 Storage section 140 Control Unit 150 Acquisition Department 151 Initial shape information acquisition unit 152 Efficiency Information Acquisition Unit 160 Decision Section 161 Calculation Section 162 Restraint part 163 Judgment Department CA pre-combustion air for heat exchange CG combustion exhaust gas CL1 First Processing CL2 Second Processing CL3 Third Processing CL4 4th process EG exhaust gas PA (Passive Air) for combustion after heat exchange R1 1st area R2 2nd area R3 3rd area

Claims

1. The system comprises a radiant tube and a recuperator provided on the radiant tube, A design apparatus for a radiant tube type heating device, wherein the recuperator mediates heat exchange between exhaust gas flowing through the radiant tube after the fuel has been burned and combustion air used for the combustion of the fuel, An acquisition unit that acquires heat exchange efficiency information relating to the efficiency of heat exchange between the exhaust gas and the combustion air, The system includes a determination unit that determines the shape of the partition wall between the exhaust gas and the combustion air based on the calculation results obtained by topology optimization using the heat exchange efficiency information. A design device for recuperators.

2. The topology optimization includes the optimization of the lattice structure. A recuperator design apparatus according to claim 1.

3. The heat exchange efficiency information includes pressure loss information relating to the pressure loss in the exhaust gas flow path and temperature information relating to the temperature of the exhaust gas. A recuperator design apparatus according to claim 1.

4. The determination unit includes a calculation unit that performs topology optimization using the pressure loss information or the temperature information as the objective function. A recuperator design apparatus according to claim 3.

5. The calculation unit performs a sensitivity analysis simulation regarding the performance of the spatial distribution of materials in the partition wall, updates the spatial distribution of materials, and performs topology optimization. A recuperator design apparatus according to claim 4.

6. The heat exchange efficiency information includes initial shape information relating to the initial shape of the partition wall. A recuperator design apparatus according to claim 1.

7. The determination unit includes a restraining unit that restricts the weight of a specific part of the recuperator to a range of less than or equal to a specified value when determining the shape of the partition wall. A recuperator design apparatus according to claim 1.

8. The determination unit includes a constraint unit that restricts the shape of the recuperator when determining the shape of the partition wall to a range that does not exceed the manufacturing performance range of the manufacturing apparatus that manufactures the recuperator. A recuperator design apparatus according to claim 1.

9. The recuperator has the exhaust gas flowing through its outer side and the combustion air flowing through its inner side. A recuperator design apparatus according to claim 1.

10. Inside the recuperator, an exhaust gas passage through which the exhaust gas flows and a combustion air passage through which the combustion air flows are formed independently of each other. A recuperator design apparatus according to claim 1.

11. The system comprises a radiant tube and a recuperator provided on the radiant tube, The computer of the design apparatus for the recuperator for a radiant tube heating device, which mediates heat exchange between exhaust gas flowing through the radiant tube after the fuel has been burned and combustion air used for the combustion of the fuel, The system acquires heat exchange efficiency information relating to the efficiency of heat exchange between the exhaust gas and the combustion air, and determines the shape of the partition wall between the exhaust gas and the combustion air based on the calculation results obtained by topology optimization using the heat exchange efficiency information. Recuperator design method.

12. The system comprises a radiant tube and a recuperator provided on the radiant tube, The computer of the design device for the recuperator for a radiant tube heating device, which mediates heat exchange between exhaust gas flowing through the radiant tube after the fuel has been burned and combustion air used for the combustion of the fuel, The system acquires heat exchange efficiency information regarding the efficiency of heat exchange between the exhaust gas and the combustion air, and determines the shape of the partition wall between the exhaust gas and the combustion air based on the calculation results obtained by topology optimization using the heat exchange efficiency information. program.

13. The system comprises a radiant tube and a recuperator provided on the radiant tube, The recuperator is a recuperator for a radiant tube heating device that mediates heat exchange between exhaust gas flowing through the radiant tube after the fuel has been burned and combustion air used for the combustion of the fuel, A recuperator designed using the recuperator design apparatus described in claim 1.

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