Distributed thermal energy distribution process for dry heat treatment of resin sand molds

Abstract

The present application relates to the technical field of industrial furnace control and efficient combustion, and discloses a distributed heat energy distribution process in the dry heat treatment stage of resin sand mold, which comprises the following steps: dividing a heating chamber into spatially independent combustion distribution intervals, determining an initial heat load distribution ratio according to the heating area and thickness parameters of the sand mold in each interval to adjust the fuel flow, and dynamically correcting the fuel flow according to the exhaust gas temperature change rate; when the fuel flow is lower than 50% of the calibrated flux, reducing the valve opening degree, linkage adjusting the cross-sectional area of the inner annular flow channel of the burner to maintain the jet velocity and adjusting the outer ring air supply pressure to maintain the total jet momentum, so that the problems of flame blowout and incomplete combustion loss caused by kinetic energy attenuation under low fuel flux are solved, and the cracking risk caused by uneven temperature rise of the sand mold is eliminated.

Description

Technical Field

[0001] This invention belongs to the field of industrial furnace control and high-efficiency combustion technology, and particularly relates to a distributed heat energy distribution process in the dry heat treatment stage of resin sand mold. Background Technology

[0002] Currently, in casting heat treatment production lines, multi-section gas-fired furnaces are a common technical solution for curing and drying irregularly shaped workpieces. By using an air-fuel ratio regulating valve in conjunction with an industrial burner, the fuel supply of each section is adjusted according to the average temperature fed back by thermocouples in the curing chamber. However, when this solution is applied to the low-temperature curing and drying conditions of resin sand molds, the furnace system significantly reduces the fuel volume flow rate to maintain low heat load requirements. The reduction in fuel flux directly disrupts the original hydrodynamic balance of the burner nozzle, causing the fluid velocity at the nozzle to drop below the jet adhesion stability threshold. The flame root loses momentum due to the loss of flow field adsorption, resulting in flameout. This disrupts the continuity of energy distribution in the drying chamber, inducing uneven distribution of resin crosslinking dynamics and structural thermal stress cracking of the molding sand.

[0003] To address the flow instability caused by a sudden drop in nozzle velocity, the conventional improvement approach of increasing the excess air coefficient to maintain nozzle momentum introduces excessive combustion-supporting cold air, reducing thermal energy conversion efficiency and generating localized transient hot spots. This accelerates the thermal decomposition of resin molecules and increases the emission of volatile organic compounds. For example, Chinese invention patent CN106918205B discloses a method for reducing invasive porosity defects in large castings and a drying oven. It achieves macroscopic hot air circulation and convection through a duct structure and a hollowed-out platform design. However, this technology is essentially a passive homogenization mechanism based on empirical layout. In actual production conditions, the resin sand mold crosslinking exothermic process is dynamic, and the solution relying on static flow field configuration cannot achieve real-time dynamic tracking of heat load requirements in specific areas. During the low-temperature curing stage from ℃ to 120℃, the furnace system significantly reduces the fuel volume flow rate to maintain a low heat load. Existing technologies do not address the core physical constraints of the burner nozzle flow field momentum. The reduced fuel flux causes the nozzle fluid velocity to drop below the jet adhesion stability threshold. The flame root loses the flow field adsorption kinetic energy, resulting in the risk of flameout or extinction. This induces uneven temperature rise in the sand mold and structural thermal stress cracking. There is a contradiction between stable combustion under low load and dynamic adjustment of the spatial directional energy field. Conventional control logic cannot reshape the flow field morphology of the nozzle reaction boundary while taking into account the precise temperature control requirements of the sand mold curing process. Conventional temperature control linkage logic cannot reshape the flow field morphology of the nozzle reaction boundary under low flux conditions, resulting in a physical conflict between the stability of the combustion fluid and the requirements of the sand mold curing process that cannot be satisfied simultaneously.

[0004] Therefore, the technical problem to be solved by this invention is how to develop a high-precision control, monitoring and alarm linkage device configuration scheme for multi-zone industrial furnaces, so as to construct a closed-loop directional heat energy supply mechanism based on the spatial geometric characteristics of the sand mold to be cured, and maintain the nozzle flow velocity and local air-fuel ratio by adjusting the flow channel cross section of the flow channel in the burner when the fuel supply is reduced, thereby providing a continuous and stable low temperature energy field distribution while eliminating the risk of flame de-ignition. Summary of the Invention

[0005] The present invention aims to solve the problems of flame detachment, increased chemical loss, and cross-linking cracking of workpiece caused by reduced nozzle velocity of burner under low load conditions.

[0006] In this technical solution, a distributed heat energy distribution process for the dry heat treatment stage of resin sand molds includes the following steps:

[0007] Step S101: Based on the heated area and thickness parameters of the sand mold to be cured in each combustion distribution zone obtained by the geometric detection device, determine the initial heat load distribution ratio of each combustion distribution zone, control the initial fuel volume flow rate of the coaxial airflow regulating burner in each combustion distribution zone, and maintain the curing temperature at 80℃ to 120℃.

[0008] Step S102: Monitor the exhaust temperature of each combustion distribution zone in real time, correct the initial heat load distribution ratio according to the rate of change of each exhaust temperature over time, determine the corrected heat load distribution ratio of each combustion distribution zone, and adjust the fuel volume flow rate entering each combustion distribution zone.

[0009] Step S103: When the corrected heat load distribution ratio decreases and causes the fuel volume flow rate to be lower than 50% of the initial calibrated volume flow rate, reduce the opening of the fuel ratio regulating valve, simultaneously control the axial displacement of the electric regulating sleeve inside the inner ring air passage of the coaxial airflow regulating burner, reduce the cross-sectional area of ​​the air flow channel of the inner ring air passage, maintain the nozzle velocity of the inner ring air passage at 15m / s to 25m / s, and lock the local excess air coefficient at the central fuel nozzle outlet of the coaxial airflow regulating burner in the range of 1.05 to 1.15.

[0010] Preferably, step S103 further includes the following sub-steps: Step S1031, the operating frequency of the outer ring combustion fan is adjusted by the frequency converter, the air supply pressure of the outer ring air passage of the coaxial airflow control burner is changed, so that the total jet flow of the mixed gas at the outer edge of the nozzle of the coaxial airflow control burner is kept above the preset flow field adhesion threshold, and the fluid adsorption effect formed by the air supply pressure causes the root of the flame formed by combustion to adhere to the outer edge of the end face of the coaxial airflow control burner.

[0011] Preferably, the method includes the following steps: Step S104, using an ultraviolet flame monitor installed on the wall of the heating chamber to monitor the characteristic wavelength radiation intensity at the nozzle of the coaxial airflow control burner online; Step S105, when the characteristic wavelength radiation intensity is lower than the preset safety threshold and the duration reaches 2s, the fuel ratio regulating valve is cut off, and the electric regulating sleeve is driven to completely close the inner ring air passage, while the air supply pressure of the outer ring air passage is increased to 1.5 times the maximum setting to purge the heating chamber in situ.

[0012] Preferably, in step S101, determining the initial heat load distribution ratio of each combustion distribution zone includes the following sub-steps: step S1011, using a spatial scanning sensor to acquire three-dimensional spatial geometric data of the sand mold to be cured in each combustion distribution zone; step S1012, based on the three-dimensional spatial geometric data, determining the heated area and thickness parameters of the sand mold to be cured in each combustion distribution zone, and matching the initial heat load distribution ratio of each combustion distribution zone.

[0013] Preferably, in step S102, real-time monitoring of the exhaust temperature of each combustion distribution zone includes the following sub-steps: Step S1021, using a thermocouple temperature sensor installed in the exhaust duct, periodically collecting the exhaust temperature of each combustion distribution zone, and calculating the first derivative of each exhaust temperature with time as the rate of change of each exhaust temperature with time.

[0014] Preferably, in step S102, the feedback correction of the initial heat load distribution ratio based on the rate of change of each exhaust temperature over time includes the following sub-steps: Step S1022, multiplying the rate of change of each exhaust temperature over time by the resin curing heat release rate feedback compensation coefficient to correct the initial heat load distribution ratio, wherein the resin curing heat release rate feedback compensation coefficient is a constant, and the value range of the resin curing heat release rate feedback compensation coefficient is from 0.15s / ℃ to 0.35s / ℃.

[0015] Preferably, after completing step S103, the following steps are also included: Step S106, collecting the solidified waste gas generated in each combustion distribution zone and introducing the solidified waste gas into the catalytic combustion chamber for catalytic combustion of the waste gas to generate high-temperature flue gas; Step S107, introducing the high-temperature flue gas into the waste heat exchanger to exchange heat with the introduced combustion air, and using the heated combustion air to supply each coaxial airflow control burner.

[0016] Preferably, in step S103, driving the electric adjusting sleeve disposed inside the inner ring air passage includes the following sub-steps: Step S1032, controlling the electric adjusting sleeve to generate axial displacement inside the inner ring air passage, adjusting the cross-sectional area of ​​the air flow channel open towards the central fuel injection pipe outlet of the inner ring air passage, thereby maintaining the nozzle flow velocity of the inner ring air passage.

[0017] Preferably, the method further includes the following steps: Step S108, before adjusting the initial fuel volume flow rate of each combustion distribution zone, controlling the opening degree of the fuel ratio regulating valve of each combustion distribution zone to adjust to the preheating opening degree range, so that the heating chamber is preheated to the preset preheating temperature range.

[0018] Compared with existing technologies, the distributed heat energy distribution process of the resin sand mold dry heat treatment stage of this invention has the following advantages:

[0019] 1. In the distributed heat energy distribution during the dry heat treatment stage of resin sand mold, the fuel supply in the combustion distribution zone is changed by the dynamic linkage of spatial geometric data and exhaust temperature change rate. Simultaneously, the electric regulating sleeve in the inner ring air channel of the coaxial airflow control burner is moved to change the flow channel cross-sectional area. When the fuel volume flow rate is at a low load, the air velocity at the nozzle is still maintained within the preset flow range. By utilizing the high-speed shearing action of local air, the local excess air coefficient at the combustion boundary is stabilized. This solves the problems of sharp drop in nozzle velocity, air-fuel ratio imbalance and chemical incomplete combustion loss caused by simply reducing the fuel supply in the traditional proportional regulation process. The system exhibits stable self-feedback regulation capability under low temperature heating conditions.

[0020] 2. By adjusting the operating frequency of the outer ring air supply fan using a frequency converter, the air supply pressure of the outer ring air channel is changed, ensuring that the total jet flow of the mixed gas at the outer edge of the coaxial airflow control burner nozzle is always maintained above the preset flow field adhesion threshold. Through the fluid adsorption effect, the root of the flame formed by combustion is continuously and tightly adhered to the outer edge of the burner end face. Under the condition of low-temperature drying treatment, the phenomenon of flame center detachment is avoided, and a continuous and stable spatial distribution of thermal energy field is provided in the drying area. This eliminates the risk of structural cracking caused by uneven heat absorption during the low-temperature curing and cross-linking stage of the sand mold, and coordinates the conflict between the low-load stable operation of the heater and the low-throughput heat absorption demand of the workpiece.

[0021] 3. Combined with the ultraviolet flame monitor installed on the wall of the heating chamber, the characteristic wavelength radiation intensity at the nozzle of the coaxial airflow control burner is monitored online. When the radiation intensity is continuously lower than the preset safety threshold, the fuel proportioning valve is cut off by the central controller, and the electric regulating sleeve is driven to completely close the inner ring air passage, forcibly increasing the air supply pressure of the outer ring air passage to the maximum set pressure. The heating chamber is purged in situ using a large volume of combustion air. This protection mechanism works in conjunction with the aforementioned flow field shaping adjustment to form an active defense barrier under non-ideal working conditions, avoiding the safety hazard of fuel accumulation caused by the risk of transient flameout due to sudden fluid disturbance, and enhancing the operational stability of the drying system in complex industrial sites. Attached Figure Description

[0022] Figure 1This is a process flow diagram of dynamic heat load adjustment and flow rate maintenance of the present invention;

[0023] Figure 2 This is a data interaction architecture diagram of the sensing and execution physical nodes of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0025] A distributed heat energy distribution process for the dry heat treatment stage of resin sand molds includes the following steps:

[0026] Step S101: Based on the heated area and thickness parameters of the sand mold to be cured in each combustion distribution zone obtained by the geometric detection device, determine the initial heat load distribution ratio of each combustion distribution zone, control the initial fuel volume flow rate of the coaxial airflow regulating burner in each combustion distribution zone, and maintain the curing temperature at 80℃ to 120℃.

[0027] Step S102: Monitor the exhaust temperature of each combustion distribution zone in real time, correct the initial heat load distribution ratio according to the rate of change of each exhaust temperature over time, determine the corrected heat load distribution ratio of each combustion distribution zone, and adjust the fuel volume flow rate entering each combustion distribution zone.

[0028] Step S103: When the corrected heat load distribution ratio decreases and causes the fuel volume flow rate to be lower than 50% of the initial calibrated volume flow rate, reduce the opening of the fuel ratio regulating valve, simultaneously control the axial displacement of the electric regulating sleeve inside the inner ring air passage of the coaxial airflow regulating burner, reduce the cross-sectional area of ​​the air flow channel of the inner ring air passage, maintain the nozzle velocity of the inner ring air passage at 15m / s to 25m / s, and lock the local excess air coefficient at the central fuel nozzle outlet of the coaxial airflow regulating burner in the range of 1.05 to 1.15.

[0029] Preferably, step S103 further includes the following sub-steps: Step S1031, the operating frequency of the outer ring combustion fan is adjusted by the frequency converter, the air supply pressure of the outer ring air passage of the coaxial airflow control burner is changed, so that the total jet flow of the mixed gas at the outer edge of the nozzle of the coaxial airflow control burner is kept above the preset flow field adhesion threshold, and the fluid adsorption effect formed by the air supply pressure causes the root of the flame formed by combustion to adhere to the outer edge of the end face of the coaxial airflow control burner.

[0030] Preferably, the method includes the following steps: Step S104, using an ultraviolet flame monitor installed on the wall of the heating chamber to monitor the characteristic wavelength radiation intensity at the nozzle of the coaxial airflow control burner online; Step S105, when the characteristic wavelength radiation intensity is lower than the preset safety threshold and the duration reaches 2s, the fuel ratio regulating valve is cut off, and the electric regulating sleeve is driven to completely close the inner ring air passage, while the air supply pressure of the outer ring air passage is increased to 1.5 times the maximum setting to purge the heating chamber in situ.

[0031] Preferably, in step S101, determining the initial heat load distribution ratio of each combustion distribution zone includes the following sub-steps: step S1011, using a spatial scanning sensor to acquire three-dimensional spatial geometric data of the sand mold to be cured in each combustion distribution zone; step S1012, based on the three-dimensional spatial geometric data, determining the heated area and thickness parameters of the sand mold to be cured in each combustion distribution zone, and matching the initial heat load distribution ratio of each combustion distribution zone.

[0032] Preferably, in step S102, real-time monitoring of the exhaust temperature of each combustion distribution zone includes the following sub-steps: Step S1021, using a thermocouple temperature sensor installed in the exhaust duct, periodically collecting the exhaust temperature of each combustion distribution zone, and calculating the first derivative of each exhaust temperature with time as the rate of change of each exhaust temperature with time.

[0033] Preferably, in step S102, the feedback correction of the initial heat load distribution ratio based on the rate of change of each exhaust temperature over time includes the following sub-steps: Step S1022, multiplying the rate of change of each exhaust temperature over time by the resin curing heat release rate feedback compensation coefficient to correct the initial heat load distribution ratio, wherein the resin curing heat release rate feedback compensation coefficient is a constant, and the value range of the resin curing heat release rate feedback compensation coefficient is from 0.15s / ℃ to 0.35s / ℃.

[0034] Preferably, after completing step S103, the following steps are also included: Step S106, collecting the solidified waste gas generated in each combustion distribution zone and introducing the solidified waste gas into the catalytic combustion chamber for catalytic combustion of the waste gas to generate high-temperature flue gas; Step S107, introducing the high-temperature flue gas into the waste heat exchanger to exchange heat with the introduced combustion air, and using the heated combustion air to supply each coaxial airflow control burner.

[0035] Preferably, in step S103, driving the electric adjusting sleeve disposed inside the inner ring air passage includes the following sub-steps: Step S1032, controlling the electric adjusting sleeve to generate axial displacement inside the inner ring air passage, adjusting the cross-sectional area of ​​the air flow channel open towards the central fuel injection pipe outlet of the inner ring air passage, thereby maintaining the nozzle flow velocity of the inner ring air passage.

[0036] Preferably, the method further includes the following steps: Step S108, before adjusting the initial fuel volume flow rate of each combustion distribution zone, controlling the opening degree of the fuel ratio regulating valve of each combustion distribution zone to adjust to the preheating opening degree range, so that the heating chamber is preheated to the preset preheating temperature range.

[0037] Example 1: In the curing and drying process of irregularly shaped resin sand molds with uneven thickness and complex cavities, the dry heat treatment furnace has 4 to 12 spatially independent combustion distribution zones that maintain the temperature in a low-temperature curing range of 80°C to 120°C. Due to the drop in heat absorption load of the molding sand within each combustion distribution zone, the centralized control system reduces the opening of the fuel ratio regulating valve, resulting in a step-like decrease in the fuel jet velocity and kinetic energy at the nozzle of the conventional industrial burner. Insufficient shear mixing occurs between the combustion air and the fuel fluid within the spatial boundary, leading to local air-fuel ratio imbalance, flame center de-ignition, and increased chemical incomplete combustion losses within the heating chamber. This causes uneven energy field distribution within the drying chamber and induces uneven local temperature rise in the resin sand mold, resulting in thermal stress cracking. The spatial scanning sensor collects data on the sand mold to be cured in the [missing information - likely a specific temperature range or measurement]. The central controller extracts the corresponding heating area from the three-dimensional spatial geometric data within each combustion distribution zone. With average thickness Calculate the initial heat load distribution ratio according to the following formula. ; ,in, and All values ​​are positive integers, and their maximum value is equal to the total number of combustion distribution intervals. , Integers between 4 and 12 For the first The heated area of ​​the sand mold to be cured within each combustion distribution zone. For the first The average thickness of the sand mold to be cured within each combustion distribution zone is calculated, with the denominator being the sum of the ratios of the heated area to the average thickness across all combustion distribution zones. The initial heat load allocation ratio is dimensionless, and the central controller determines the allocation ratio based on this ratio. Calculate and generate the initial fuel volumetric flow rate command for the coaxial airflow control burner, and adjust the fuel volumetric flow rate delivered to this range. In the initial stage of drying in a dry heat treatment furnace, the formula includes the average thickness of the sand mold to be cured. Placed in the denominator, it is used to limit the surface heat flux density of thick parts in the early stage of resin crosslinking, reduce the transient thermal stress gradient between the surface and interior induced by the phase lag of heat conduction inside the sand mold, and avoid thermal stress cracking of the surface sand mold. Under no-load debugging state, the thickness parameters of the sand mold to be cured in different areas are obtained by spatial scanning sensors and a spatial geometric matrix is ​​established. The control system limits the fuel volume flow rate entering the combustion distribution zone corresponding to the thick wall in the initial stage according to the spatial geometric matrix, so that the initial heat intensity of the combustion distribution zone with smaller thickness is greater than that of the combustion distribution zone with larger thickness, and controls the transient heat flux density of the thick wall surface within the non-cracking creep working window of 12 kW to 15 kW per square meter.

[0038] Thermocouple temperature sensors installed in the exhaust duct periodically collect exhaust temperatures for each combustion distribution zone with independent time steps of 10 seconds. The central controller calculates the first derivative of the exhaust temperature with time as the rate of change of the exhaust temperature over time. The initial heat load distribution ratio is corrected according to the following formula two. This determines the corrected heat load distribution ratio. ; ,in, For the first Corrected heat load distribution ratio for each combustion distribution zone The feedback compensation coefficient for the resin curing exothermic rate is a constant, and its value is 0.25 s / ℃. The central controller adjusts the heat load distribution ratio based on the rate of change of exhaust temperature over time. Adjust the fuel volumetric flow rate entering each combustion distribution zone to the corrected fuel volumetric flow rate. When the heat load distribution ratio is adjusted When the fuel volumetric flow rate is reduced to below 50% of the initial calibrated volumetric flow rate, the central controller reduces the opening of the fuel proportional control valve and simultaneously controls the axial displacement of the electrically operated regulating sleeve inside the inner annular air passage of the coaxial airflow control burner. This reduces the cross-sectional area of ​​the airflow passage within the inner annular air passage, maintaining the nozzle velocity within the inner annular air passage at 15 m / s to 25 m / s, thereby reducing the local excess air coefficient at the central fuel injector outlet. Locked within the range of 1.05 to 1.15, under low-load conditions where the fuel volumetric flow rate is less than 50% of the initial calibrated volumetric flow rate, the local excess air coefficient will be reduced. Locked within the range of 1.05 to 1.15, the central controller stores a one-dimensional mapping table of valve opening and sleeve displacement generated during hot-state calibration. During the hot-state calibration operation of the dry heat treatment furnace, the exhaust oxygen content is monitored by an electrochemical flue gas analyzer installed at the reaction boundary of the coaxial airflow regulating burner nozzle. As the fuel proportioning valve opening is gradually adjusted from 100% to 20%, the number of step pulses for the axial displacement of the electric regulating sleeve is finely adjusted to reduce the local excess air coefficient.To stabilize at the target value of 1.10, a one-dimensional mapping table is established by recording the target step pulse count of the electric regulating sleeve corresponding to different fuel ratio regulating valve openings. Specifically, the one-dimensional mapping table is stored in the read-only memory unit of the central controller in the form of a digital matrix. It contains multiple sets of calibration data pairs solidified during the hot commissioning phase. For example, when the regulating valve opening is recorded as 50%, 45%, 40%, 35%, and 30%, the corresponding target step pulse count of the electric regulating sleeve is set to 1200 steps, 1450 steps, 1700 steps, 1950 steps, and 2200 steps, respectively. In the actual operation process, when the real-time valve opening read by the central controller is between the above adjacent discrete calibration points, the built-in standard linear interpolation algorithm automatically calculates... The precise target step pulse number corresponding to the current valve opening is obtained, which drives the electric regulating sleeve to perform continuous and smooth axial displacement. In the actual operation process of the furnace, the central controller reads the corrected fuel volume flow rate every 100 milliseconds and retrieves the corresponding one-dimensional mapping table, writes the displacement control word to the electric regulating sleeve drive register, and controls the air flow channel cross-sectional area to be limited to the fully open state of 31.4% to 45.1%. Without relying on real-time flue gas online monitoring, the air-fuel ratio at the reaction boundary is rigidly locked by actively limiting the flow channel cross-sectional area. For different basic heat load benchmarks and different batches of fuel composition changes, the generation rule of this one-dimensional mapping table is determined by the pre-heated benchmark calibration process. The specific operation is as follows: under the benchmark total heat load, control the fuel... The fuel proportioning valve opening decreases in 5% increments. The oxygen content (volume percentage) in the exhaust gas is monitored online. The pulse count of the electric regulating sleeve is manually adjusted until the oxygen content (volume percentage) stabilizes within the target range of 2.1% to 3.5%. The recorded relationship between the opening and the pulse count is then written into a one-dimensional mapping table. If the fuel's calorific value fluctuates, the target pulse count in the table is adjusted proportionally according to the calorific value deviation, ensuring the universal applicability of the flow control ratio under low-load conditions. The frequency converter adjusts the operating frequency of the outer ring combustion fan to change the air supply pressure of the outer ring air passage, maintaining the total jet flow of the mixed gas at the outer edge of the coaxial airflow-controlled burner nozzle above the preset flow field adhesion threshold. This is achieved by adjusting the air supply pressure. The fluid adsorption effect causes the flame root formed by combustion to adhere to the outer edge of the end face of the coaxial airflow-controlled burner. The preset flow field adhesion threshold is defined as the critical negative pressure value at the outer edge of the end face of the coaxial airflow-controlled burner. During the pre-cold commissioning stage, a high-frequency pressure sensor is attached to the outer edge of the end face of the coaxial airflow-controlled burner. Under low-load conditions with the fuel ratio regulating valve opening reduced, a local negative pressure is generated at the outer edge of the end face by the jet entrainment effect. When the absolute value of the local negative pressure is lower than 0.15 kPa, the photoelectric flame monitor detects the flame root flickering and detachment signs. When the absolute value of the local negative pressure is maintained between 0.25 kPa and 0.40 kPa, the flame root is stably attached to the nozzle end face, and the preset flow field adhesion threshold is determined to be negative 0 on the gauge pressure.In the distributed heat energy distribution control process of the dry heat treatment furnace, the central controller reads the instantaneous air supply pressure at the outlet of the outer ring air channel and links the frequency converter to adjust the operating frequency of the outer ring combustion fan, controlling the absolute value of the local negative pressure at the outer edge of the end face to be maintained above 0.20 kPa. Through the fluid adsorption effect formed by the air supply pressure, the flame root continuously adheres to the outer edge of the coaxial airflow regulating burner end face, eliminating local flameout and incomplete combustion caused by the decay of fuel kinetic energy under low load. In this control process, the internal register of the central controller is pre-loaded with an analytical conversion mathematical model between the instantaneous air supply pressure at the outlet of the outer ring air channel and the local negative pressure at the outer edge of the end face. This model is based on the fluid wall-attached entrainment jet equation, that is, the absolute value of the local wall-attached negative pressure at the outer edge of the end face and the square root of the positive air supply pressure at the outlet of the upstream outer ring air channel show a positive correlation causal mapping relationship. This analytical conversion mathematical model is specifically expressed as a pure text polynomial conversion logic. The algorithm calculates the absolute value of the local negative pressure at the outer edge of the burner end face by multiplying the square root of the input air supply pressure by a fixed flow field entrainment ratio coefficient and subtracting the end-face friction loss constant. The flow field entrainment ratio coefficient is set to 0.35, and the end-face friction loss constant is set to 0.05 kPa. The calculated output value is the estimated scalar value of the absolute value of the local negative pressure at the outer edge of the burner end face. Through linear transformation of this polynomial, the positive pressure signal of the macroscopic channel is converted into a digital index of the adhesion strength of the negative pressure in the micro-region without delay. This provides deterministic digital source data for the control loop. After the central controller reads the value from the outer loop positive pressure sensor in real time, it can indirectly and accurately deduce the current estimated value of the local negative pressure at the outer edge of the burner end face through this analytical conversion model. This estimated value is then used as feedback input to the closed-loop control loop to adjust the inverter frequency, thus ensuring that closed-loop rigid control of the absolute value of the local negative pressure at the outer edge of the burner end face can still be achieved without directly placing sensors in the high-temperature reaction micro-region at the burner end face.

[0039] The dynamic linkage between the cross-sectional area adjustment of the airflow channel of the coaxial airflow control burner and the outer ring air supply pressure ensures that the system maintains the airflow velocity at the nozzle even when the fuel flow is at a low load. The high-speed shearing action of the local air stabilizes the local excess air coefficient at the combustion boundary, avoiding the sharp drop in nozzle velocity, air-fuel ratio imbalance, and increased chemical incomplete combustion losses caused by simply reducing the fuel supply. Under the drying conditions of 80℃ to 120℃, the flame center de-seated and detached phenomenon is avoided. The thermal energy field in the drying area presents a spatially continuous and stable distribution. The structural cracking caused by uneven heat absorption during the low-temperature curing and cross-linking stage of the molding sand is eliminated, achieving a fluid dynamic balance between the low-load operation of the heater and the low-flux heat absorption demand of the molding sand.

[0040] Example 2: When the system faces the complex heat load variation of resin sand mold dry heat treatment test conditions, the test platform includes a heat treatment furnace with 6 spatially independent combustion distribution zones. The thermocouple temperature sensors have a temperature measurement resolution of 0.1℃, the mass flow meter has a flow detection accuracy of 0.01m³ / h, and the coaxial laser scanning measurement device has a spatial geometric configuration resolution of 0.2mm. To test the temperature field control stability and anti-interference capability of the test process in a real, non-ideal industrial furnace environment, the signal transmission link actively superimposes Gaussian white noise with a signal-to-noise ratio of 20dB. Simultaneously, the thermodynamic distribution superimposes power frequency thermal field harmonic fluctuations with an amplitude of 1.5℃ as a background interference source. The data sampling period for collecting the exhaust temperature of each combustion distribution zone is set to 10s. The selection of this parameter depends on the technical trade-off between the real-time performance of data tracking and the computational load of the central controller, based on the maximum high-frequency discrete fluctuation boundary of the exhaust temperature change rate. Limited to within 0.5℃ / s, according to the Nyquist sampling theorem, to avoid signal aliasing during the temperature differential term calculation process and to control the interrupt handling overhead of the central controller to be less than 1%, the data sampling period was determined to be 10s to establish a historical database. The experiment was divided into three independent sample groups to verify the process temperature endpoints and median points defined within the technical scope. Sample group one set the curing temperature at the lower limit of 80℃ and adjusted the resin curing heat release rate feedback compensation coefficient to the lower limit of 0.15s / ℃. Sample group two set the curing temperature at the median point of 100℃ and set the resin curing heat release rate feedback compensation coefficient to the median point of 0.25s / ℃. Sample group three set the curing temperature at the upper limit of 120℃ and set the resin curing heat release rate feedback compensation coefficient to the upper limit of 0.35s / ℃. In the initial heat distribution stage, the central controller calculated the initial heat load distribution ratio of each combustion distribution zone according to the formula. ; ,in, and All values ​​are positive integers, and their maximum value is equal to the total number of combustion distribution intervals. , Integers between 4 and 12 For the first The heated area of ​​the sand mold to be cured within each combustion distribution zone, in units of , For the first The average thickness of the sand mold to be cured within each combustion distribution zone is calculated, with the denominator being the sum of the ratios of the heated area to the average thickness across all combustion distribution zones. The initial heat load allocation ratio is determined by thermocouple temperature sensors periodically collecting the exhaust temperature of each zone. The central controller then adjusts the initial heat load allocation ratio according to Formula 2. And calculate the corrected heat load distribution ratio. ; ,in, For the first Corrected heat load distribution ratio for each combustion distribution zone The feedback compensation coefficient for the resin curing exothermic rate is denoted as 0.15 s / ℃ to 0.35 s / ℃. This represents the rate of change in exhaust temperature.

[0041] A coaxial laser scanning measurement device measures irregularly shaped resin sand molds to obtain their heated area within the first combustion distribution zone. It is 2.45 average thickness The initial heat load distribution ratio is calculated to be 0.08m. Given a value of 0.18, the initial fuel volumetric flow rate under this spatial geometric topological constraint is... Set to 12.40 The baseline flux, as the curing and crosslinking reaction progresses to the exothermic section, is used as the rate of change of exhaust temperature measured by thermocouple temperature sensors. The rate is 0.12℃ / s. The central controller, based on Formula 2 mentioned above, and in conjunction with the lower limit of 0.15s / ℃ for the resin curing exothermic rate, provides a feedback compensation coefficient. Calculate the corrected heat load distribution ratio The value is 0.183, so the fuel input at the nozzle is changed accordingly to correct the fuel volumetric flow rate. Adjusted to 5.91 At this point, the fuel volumetric flow rate drops by 52.3% compared to the rated flux. The central controller reduces the opening of the fuel proportional control valve, simultaneously driving the electric regulating sleeve in the inner annular air passage to move, reducing the cross-sectional area of ​​the air passage to 45.1% of its fully open state. At this time, the nozzle velocity of the inner annular air passage is maintained at 16.4 m / s, reducing the local excess air coefficient at the reaction boundary at the central fuel nozzle outlet. The rigidity was locked at 1.06, and the frequency of the outer ring combustion fan was simultaneously adjusted to 32.4Hz to regulate the air supply pressure. The total jet flux of the mixed gas at the outer edge of the nozzle was measured to be 1.12 times the preset flow field adhesion threshold, so that the flame root adhered to the outer edge of the nozzle end face. At this time, the original exhaust temperature fluctuation amplitude, including background noise, decreased from 3.5℃ to 0.6℃, and the maximum temperature field uniformity deviation of the molding sand structure was only 3.2℃. In the test procedure of sample group two of this invention, the curing temperature was controlled at 100℃, and the resin curing exothermic rate feedback compensation coefficient was... Set at 0.25 s / ℃, when the fuel flux decreases by 61.2% due to the heat attenuation during molding sand drying, the fuel volumetric flow rate is corrected. It dropped to 4.81 At that time, the central controller reduced the flow channel cross-sectional area to 38.2% of the fully open state, and the measured inner ring nozzle velocity stabilized at 19.5 m / s, with a local excess air coefficient. Locked at 1.11, the frequency of the outer ring combustion fan was adjusted to 28.1Hz, the total jet flux remained at 1.18 times the preset flow field adhesion threshold, the processed exhaust temperature signal was filtered to remove Gaussian white noise disturbances, the temperature field uniformity deviation converged to 1.8℃, and no flameout interruption occurred; in the test process of sample group three of this invention, the curing temperature was controlled at the upper limit of the process 120℃, and the resin curing exothermic rate feedback compensation coefficient was... Using an upper limit of 0.35 s / ℃, when the system fuel flux decreases by 68.5%, the corrected fuel volumetric flow rate is determined. It dropped to 3.91 At that time, the cross-sectional area of ​​the inner ring airflow channel was restricted to 31.4% of its fully open state, and the measured nozzle velocity remained at 23.2 m / s, with a local excess air coefficient. With the frequency locked at 1.14 and the outer ring fan frequency controlled at 24.5Hz, the flame was closely attached to the outer edge of the coaxial airflow regulating burner, and the temperature field uniformity deviation of the molding sand structure was measured to be 2.7℃.

[0042] To verify the rationality of optimizing the process-defined protection boundary, two out-of-range control groups were established for testing nonlinear effects and performance inflection points. One out-of-range control group used the resin curing exothermic rate as a feedback compensation coefficient. The pressure was lowered to 0.12 s / ℃ to be below the lower limit. However, due to the excessively low compensation coefficient, the fuel tracking response lagged behind the crosslinking exothermic peak, reaching 42.0 s. Heat accumulation caused the exhaust temperature to rise monotonically to 134.2 ℃, resulting in irreversible structural overheating decomposition of the molding sand and a surge in volatile organic compound (VOC) emission concentration to 164.3 mg / L. The key performance indicators showed flat saturation and rapid deterioration, exhibiting incompatibility limitations beyond the boundary. The control group two, which exceeded the range, used the resin curing exothermic rate feedback compensation coefficient. The pressure was increased to 0.38 s / ℃ to exceed the upper limit. The excessively high feedback coefficient caused the control loop to fall into a nonlinear saturation oscillation state. The fuel proportional control valve fluctuated violently between 15% and 85% opening within a 20-s cycle, causing the nozzle velocity to frequently exceed the 28.5 m / s flameout limit and drop to the 11.2 m / s flashback boundary. Periodic flame detachment and extinction occurred at the bottom of the flame, and the temperature field uniformity deviation increased to 14.3℃. Irregular fractures occurred inside the sand mold due to sudden thermal stress changes, indicating that the system experienced control saturation and sudden performance degradation after exceeding the limit. At the same time, the experimental design included two partially missing control groups to verify the synergistic effect of spatial rheology and energy field between various technical features. The first partially missing control group selectively removed the dynamic shaping control of the inner ring air channel cross-sectional area while maintaining feedback correction. When the process load dropped and the fuel volume flow rate was corrected... Dropped to 4.81 At that time, because the electric regulating sleeve remained stationary, the unrestricted open cross-sectional area caused the nozzle velocity in the inner annular air passage to drop sharply to 6.2 m / s, and the local excess air coefficient at the reaction boundary... A deviation of 2.45 resulted in large-area flame flare-off and extinguishment, deteriorated chemical combustion, and increased losses by 34.2%. The temperature field deviation inside the furnace expanded to 11.5℃, indicating that single temperature adjustment could not achieve the expected results without cross-sectional dynamic control. The partial missing control group II removed the spatial geometric heat flux distribution calculation based on the initial heat load distribution ratio and adopted conventional pure temperature feedback to equally supply fuel to each zone, based on the average thickness of the molding sand. Under conditions where a non-uniform mass distribution of 40mm to 280mm occurs within each combustion distribution zone, due to the initial fuel volumetric flow rate... Lacking a causal constraint between heated area and thickness, the molding sand in the thin-walled section experiences localized overheating and cracking at 145.0℃, while the temperature deep within the thick-walled cavity fails to reach the curing threshold, with localized under-curing temperatures as low as 62.0℃. Finished product testing shows an overall scrap rate rising to 18.5%. Due to the lack of deep coordination between geometric morphology proportions, dynamic feedback, and flow field shaping, independent single-unit control induces energy field imbalance, confirming that the complete feature combination possesses interdependent system-level nonlinear technical gains. The objective results of the aforementioned multi-dimensional gradient comparison experiments demonstrate that this process method, through initial geometric thermal load... The configuration, exhaust differential dynamic correction, and linkage between the nozzle airflow cross-sectional area and the air supply pressure lock the local air-fuel ratio and the total momentum of the jet flow field under low fuel flow conditions. The system provides a continuous and stable low-temperature energy field distribution while completely eliminating the risk of flame detachment. It solves the bottleneck of incomplete chemical combustion loss and molding sand cross-linking thermal stress cracking caused by kinetic energy decay during conventional proportional regulation. The comprehensive energy consumption and exhaust emission indicators of the dry heat treatment stage are quantitatively suppressed. The distributed heat energy distribution process of the resin sand mold dry heat treatment stage meets the practical requirements of industrial production.

[0043] Example 3: This example combines Figures 1 to 2 The distributed heat energy distribution process during the dry heat treatment stage of resin sand molds is described, such as... Figure 1 As shown, the initial distribution ratio determination step is performed based on the area and thickness parameters provided by the geometric detection device. The initial fuel flow rate is controlled to maintain the temperature between 80 and 120°C and then the heat load ratio correction step is entered. This step is based on the exhaust temperature data obtained by the thermocouple temperature sensor for feedback correction. The flow rate is judged to see if it falls below the threshold, i.e., below 50% of the calibration. If the judgment is not correct, the control loop returns to the step of correcting the heat load ratio based on the exhaust temperature feedback. If the judgment is correct, the steps of reducing the opening of the regulating valve and controlling the axial displacement of the sleeve are executed sequentially, and further the process of reducing the cross-sectional area of ​​the flow channel to maintain the flow velocity stability coefficient is carried out.

[0044] like Figure 2 As shown, to support the accurate acquisition of the aforementioned process flow data and the issuance of control commands, corresponding hardware nodes and interactive signals are distributed in the field sensing and measurement nodes, the central control and drive nodes, the field actuator nodes, and the physical framework of the industrial furnace. Specifically, the spatial scanning sensor within the field sensing and measurement node is used to acquire the three-dimensional spatial geometric data of the sand mold to be cured; the thermocouple temperature sensor is used to acquire the gas temperature of the exhaust duct in each distribution zone; and the ultraviolet flame monitor is used to monitor the characteristic wavelength radiation intensity at the nozzle online. The data acquired by these three sensing and measurement devices are all directionally transmitted to the central controller within the central control and drive node. This central controller performs logical operations to calculate the initial distribution ratio and dynamically correct the load. Simultaneously, the central controller sends adjustment signals to the frequency converter within the same node to adjust... The operating frequency and supply pressure of the outer ring combustion fan are adjusted, and the central controller sends instructions to the fuel proportioning valve in the field actuator node to adjust the initial volume flow rate of fuel entering each zone, and sends instructions to the electric regulating sleeve to adjust the cross-sectional area of ​​the inner ring air channel through axial displacement. The outer ring combustion fan, which receives the frequency converter adjustment signal, performs the action of supplying air to the outer ring air channel to maintain the total jet flow. The physical output terminals of the fuel proportioning valve, electric regulating sleeve and outer ring combustion fan are all connected to the coaxial airflow control burner in the physical framework of the industrial furnace. The coaxial airflow control burner organizes the inner and outer ring airflow and stabilizes the flame at the nozzle reaction boundary. Finally, the coaxial airflow control burner applies heat to the combustion distribution zone of the heating chamber, thereby implementing directional distributed heat energy distribution to the sand mold to be cured.

[0045] Example 4: In the dry heat treatment process of irregularly shaped resin sand molds with uneven thickness and mass distribution, the distributed control system regulates multiple spatially independent combustion distribution zones inside the furnace to control the temperature in the drying chamber between 80°C and 120°C. When facing a low-load condition where the corrected fuel volume flow rate is lower than 50% of the initial calibrated volume flow rate due to the slippage of the molding sand heat absorption load, the reduction of the fuel ratio regulating valve opening to adjust the total heat supply can easily induce the dissipation of shear momentum at the nozzle position of the coaxial airflow control burner. This results in jet entrainment lag and axial drift of the flame front, causing the flame root to detach from the nozzle end face of the coaxial airflow control burner and resulting in local flameout and extinguishing. It also causes chemical incomplete combustion loss and energy field distribution imbalance in the drying chamber. During the low-temperature cross-linking and curing stage, the irregularly shaped resin sand mold experiences structural thermal stress cracking due to uneven local temperature rise.

[0046] To characterize the changes in coaxial gas shear stress and nozzle jet mass under low-load operation, this process uses the product of the instantaneous flow velocity in the inner annular air passage and the supply air pressure in the outer annular air passage as a parameter. The degree of flow field dissipation is determined by calculating the relative decrease of this parameter within the discrete sampling period. In specific control operations, the rate of change of exhaust temperature measured by the thermocouple temperature sensor in the exhaust duct is used. The input terminal is characterized by a flow rate of -0.05℃ / s, and the flow control bus has a control word update rate of no less than 10Hz to enable the environment. The central controller reads the current stepper motor pulse count value of the electric regulating sleeve as 1500, and the feedback frequency of the outer ring combustion fan frequency converter is 35.0Hz. It calculates and generates the initial ratio constant. When the fuel proportional regulating valve opening is reduced from 60% to 25%, the pressure differential transmitter measures that the instantaneous flow velocity in the inner ring drops to 11.2m / s, and the pressure sensor measures that the instantaneous pressure in the outer ring drops to 1.2kPa. Based on the aforementioned parameters, the central controller calculates and generates the dimensionless flow field momentum decay index. Flow field momentum decay index The specific calculation formula is as follows: ,in, For the first The flow field momentum decay index of each combustion distribution zone It is a positive integer and its maximum value is equal to the total number of combustion distribution intervals. , Integers between 4 and 12 The instantaneous airflow velocity at the nozzle of the inner ring air passage. The instantaneous air supply pressure is collected by a pressure sensor at the outlet of the outer ring air duct. The inner loop reference velocity constant is set to 20.0 m / s. The outer ring reference air supply pressure constant is set at 2.5 kPa; from the perspective of engineering fluid mechanics principles, the flow field momentum decay index... Using the inner ring air channel velocity air supply pressure of the outer ring air channel The product is used as the core calculation term because of the outer ring air supply pressure. Macroscopically, the total jet ejection dynamic pressure of the outer ring air is determined. The product of these two factors essentially constitutes a nonlinear composite engineering proxy that can effectively characterize the overall kinetic energy of the coaxial dual jets and the entrainment shear strength of the mixing layer. This proxy is then multiplied by the reference constant under full load boundary conditions. Ratio calculations eliminate the disorder caused by direct manipulation of different dimensions, normalizing them into dimensionless relative scalars that accurately reflect the degree to which the flow field deviates from the ideal state. In the coaxial jet shear mixing boundary layer, the outer ring air supply pressure is converted into the dynamic pressure of the outer ring airflow through the geometric contraction of the nozzle, while the inner ring air velocity determines the momentum-flow rate of the inner ring airflow. The product of the two is physically mapped to the total axial kinetic energy flux density of the nozzle mixing micro-region through the kinetic energy-momentum exchange mechanism of the fluid shear boundary layer. The level of the inner ring velocity reflects the tangential velocity gradient of the central shear flow layer, while the magnitude of the outer ring pressure determines the centripetal constraint force of the externally enveloping airflow. This cross-correlation term of velocity and pressure can characterize the kinetic energy dissipation rate of coaxial fluid under low-load conditions due to airflow decoupling across scales, thus logically forming a dimensionless normalized benchmark that is uniformly mapped to the stability evaluation of the mixing flow field. The control action threshold is set to 0.40, the clear engineering significance of which is that when the calculated When the relative decrease in total kinetic energy of the mixed jet exceeds 40%, the localized negative pressure on the nozzle outer edge caused by jet entrainment will drop to a critical instability state, and the flame root will lose its adsorption kinetic energy. Therefore, 0.40 constitutes the active physical defense boundary for the system to fully activate the flow channel cross-sectional area limitation and the fan frequency conversion boosting compensation. The central controller adopts independent short-act control of the entire link timing progression, and reads the corrected fuel volume flow rate of the current combustion distribution range through the data bus. The current flux is 3.85 m³ / h. This value is compared with the initial calibrated volumetric flow rate reference value of 8.00 m³ / h stored in the central controller's memory unit. The current flux is determined to be 48.125% of the reference value, triggering a low-load adjustment procedure. The central controller will then calculate the generated flow field momentum decay index. Compare the value with the built-in control action threshold of 0.40, when the flow field momentum decay index... When the value is greater than 0.40, the central controller determines the flow field momentum decay index. The specific numerical calculation of the target pulse number of the stepper motor is used to write the stepping opening control word to the address of the driver register of the electric adjusting sleeve. This controls the electric adjusting sleeve to move 15.5mm towards the nozzle to reduce the cross-sectional area, causing the nozzle velocity in the inner annular air passage to reverse from 11.2m / s to 18.5m / s, thereby reducing the local excess air coefficient at the reaction boundary of the central fuel injector outlet. Locked within the reaction range of 1.10; the central controller synchronously writes frequency conversion adjustment instructions to the frequency setting register of the outer ring combustion fan frequency converter, adjusting the working frequency from 35.0Hz to 42.5Hz, increasing the air supply pressure of the outer ring air channel, so that the total jet flow of the fluid adsorption effect generated by the air supply pressure difference is restored to above the preset flow field adhesion threshold.

[0047] The cross-sectional area of ​​the airflow channel in the coaxial airflow control burner is adjusted in conjunction with the air supply pressure of the outer ring air passage. This maintains the air velocity at the nozzle when the fuel flow is at a low load, and the air shearing action stabilizes the local excess air coefficient at the reaction boundary of the central fuel injector outlet. When fuel supply is reduced, the nozzle flow rate, air-fuel ratio and degree of complete chemical combustion are maintained within the preset technical indicators. At a curing temperature of 80℃ to 120℃, the flame center is attached to the nozzle seat. The thermal energy field in the curing area is kept in a uniform distribution state. The temperature difference of each part of the molding sand in the low-temperature curing and cross-linking stage is lower than the preset stress threshold. The dry heat treatment furnace body operates continuously under low load conditions.

[0048] Example 5: When the system faces the pre-deployment and commissioning of a newly installed furnace, the central controller sends a unidirectional cold flow field test signal in the initial state where the resin sand mold is not loaded and the furnace body is at normal temperature and pressure. The frequency converter drives the outer ring combustion fan to run at the maximum output frequency of 50.0Hz for 300s. Pressure sensors set inside each combustion distribution zone collect the stable pressure value at the outlet of the outer ring air channel. When the transient air supply pressure variance of 20 consecutive sampling points is less than the preset flow fluctuation threshold of 0.01kPa², the central controller reads the average instantaneous air supply pressure output by each pressure sensor and writes it into the storage unit to determine the outer ring reference air supply pressure constant of the outer ring air channel under full load boundary. Simultaneously, a handheld thermal anemometer is inserted into the center of the nozzle throat section of the inner ring air passage to measure the nozzle flow velocity. The operator inputs the measured flow velocity values ​​at each nozzle into the read-only memory of the central controller via an input terminal. These values ​​are used as the inner ring reference flow velocity constant for each coaxial airflow control burner under full load conditions. .

[0049] The central controller continuously reduces the opening of the fuel proportioning valve corresponding to the central fuel nozzle from 100% to 20% in 5% increments, while simultaneously monitoring the adhesion status of the flame root via a photoelectric flame monitor. When the reduction in the opening of the fuel proportioning valve in the first combustion distribution zone causes the process load to drop below 50%, the instantaneous air velocity at the nozzle of the inner ring air passage and the instantaneous pressure of the outer ring air passage are coupled and reduced. At the critical moment when the photoelectric flame monitor detects the flame flickering action, the central controller reads that the instantaneous air velocity in the inner ring is 15.0 m / s and the instantaneous pressure in the outer ring is 2.0 kPa, and calculates the control action threshold according to Formula 3. ; ,in, To control the action threshold, it is a dimensionless coefficient. The instantaneous air velocity measured at the critical point where the flame begins to dissipate. The instantaneous air supply pressure measured at the critical point where the flame begins to disengage. The inner loop reference velocity constant is... The outer ring reference air supply pressure constant, the calculated value of 0.40 is solidified as the control action threshold for expressing the flow field dissipation state in the subsequent differential solidification process, and the initial parameters of each combustion distribution zone are set in the thermal commissioning process.

[0050] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A distributed thermal energy distribution process for the dry heat treatment stage of a resin sand mold, characterized by, Includes the following steps: Step S101: Based on the heated area and thickness parameters of the sand mold to be cured in each combustion distribution zone obtained by the geometric detection device, determine the initial heat load distribution ratio of each combustion distribution zone, control the initial fuel volume flow rate of the coaxial airflow regulating burner in each combustion distribution zone, and maintain the curing temperature at 80℃ to 120℃. Step S102: Monitor the exhaust temperature of each combustion distribution zone in real time, correct the initial heat load distribution ratio according to the rate of change of each exhaust temperature over time, determine the corrected heat load distribution ratio of each combustion distribution zone, and adjust the fuel volume flow rate entering each combustion distribution zone. Step S103: When the corrected heat load distribution ratio decreases and causes the fuel volume flow rate to be lower than 50% of the initial calibrated volume flow rate, reduce the opening of the fuel ratio regulating valve, simultaneously control the axial displacement of the electric regulating sleeve inside the inner ring air passage of the coaxial airflow regulating burner, reduce the cross-sectional area of ​​the air flow channel of the inner ring air passage, maintain the nozzle velocity of the inner ring air passage at 15m / s to 25m / s, and lock the local excess air coefficient at the central fuel nozzle outlet of the coaxial airflow regulating burner in the range of 1.05 to 1.

15.

2. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, Step S103 further includes the following sub-steps: Step S1031, the operating frequency of the outer ring combustion fan is adjusted by the frequency converter, the air supply pressure of the outer ring air channel of the coaxial airflow control burner is changed, so that the total jet flow of the mixed gas at the outer edge of the nozzle of the coaxial airflow control burner is kept above the preset flow field adhesion threshold, and the fluid adsorption effect formed by the air supply pressure causes the root of the flame formed by combustion to adhere to the outer edge of the end face of the coaxial airflow control burner.

3. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, Includes the following steps: Step S104: Use an ultraviolet flame monitor installed on the wall of the heating chamber to monitor the characteristic wavelength radiation intensity at the nozzle of the coaxial airflow control burner online; Step S105: When the characteristic wavelength radiation intensity is lower than the preset safety threshold and the duration reaches 2s, cut off the fuel ratio regulating valve and drive the electric regulating sleeve to completely close the inner ring air passage, while increasing the air supply pressure of the outer ring air passage to 1.5 times the maximum setting, and purging the heating chamber in situ.

4. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, In step S101, determining the initial heat load distribution ratio of each combustion distribution zone includes the following sub-steps: Step S1011, using a spatial scanning sensor to acquire three-dimensional spatial geometric data of the sand mold to be cured in each combustion distribution zone; Step S1012, based on the three-dimensional spatial geometric data, determining the heated area and thickness parameters of the sand mold to be cured in each combustion distribution zone, and matching the initial heat load distribution ratio of each combustion distribution zone.

5. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, In step S102, real-time monitoring of the exhaust temperature of each combustion distribution zone includes the following sub-steps: Step S1021, using a thermocouple temperature sensor installed in the exhaust duct, periodically collect the exhaust temperature of each combustion distribution zone, and calculate the first derivative of each exhaust temperature with time as the rate of change of each exhaust temperature with time.

6. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, In step S102, the feedback correction of the initial heat load distribution ratio based on the rate of change of each exhaust temperature over time includes the following sub-steps: Step S1022, multiply the rate of change of each exhaust temperature over time by the resin curing heat release rate feedback compensation coefficient to correct the initial heat load distribution ratio, wherein the resin curing heat release rate feedback compensation coefficient is a constant, and the value range of the resin curing heat release rate feedback compensation coefficient is from 0.15s / ℃ to 0.35s / ℃.

7. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, After completing step S103, the following steps are also included: Step S106, collect the solidified waste gas generated in each combustion distribution zone, and introduce the solidified waste gas into the catalytic combustion chamber for catalytic combustion of waste gas to generate high-temperature flue gas; Step S107, introduce the high-temperature flue gas into the waste heat exchanger to exchange heat with the introduced combustion air, and use the heated combustion air to supply each coaxial airflow control burner.

8. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, In step S103, driving the electric adjusting sleeve located inside the inner ring air passage includes the following sub-steps: Step S1032, controlling the electric adjusting sleeve to generate axial displacement inside the inner ring air passage, adjusting the cross-sectional area of ​​the air flow channel open towards the central fuel injector outlet of the inner ring air passage, thereby maintaining the nozzle flow velocity of the inner ring air passage.

9. The distributed heat energy distribution process for the dry heat treatment stage of resin sand mold according to claim 1, characterized in that, It also includes the following steps: Step S108: Before adjusting the initial fuel volume flow rate of each combustion distribution zone, control the opening degree of the fuel proportion regulating valve of each combustion distribution zone to adjust to the preheating opening degree range, so that the heating chamber is preheated to the preset preheating temperature range.

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