The temperature control of the large-scale vertical quench furnace is very difficult due to its huge volume and complex thermal exchanges. To meet the technical requirement of the quenching process, a temperature cont...The temperature control of the large-scale vertical quench furnace is very difficult due to its huge volume and complex thermal exchanges. To meet the technical requirement of the quenching process, a temperature control system which integrates temperature calibration and temperature uniformity control is developed for the thermal treatment of aluminum alloy workpieces in the large-scale vertical quench furnace. To obtain the aluminum alloy workpiece temperature, an air heat transfer model is newly established to describe the temperature gradient distribution so that the immeasurable workpiece temperature can be calibrated from the available thermocouple temperature. To satisfy the uniformity control of the furnace temperature, a second order partial differential equation(PDE) is derived to describe the thermal dynamics inside the vertical quench furnace. Based on the PDE, a decoupling matrix is constructed to solve the coupling issue and decouple the heating process into multiple independent heating subsystems. Then, using the expert control rule to find a compromise of temperature rising time and overshoot during the quenching process. The developed temperature control system has been successfully applied to a 31 m large-scale vertical quench furnace, and the industrial running results show the significant improvement of the temperature uniformity, lower overshoot and shortened processing time.展开更多
Based on the analysis and investigation of calibration systems for high-accuracy low temperature thermometers,a new facility for automatic calibration of high-accuracy low temperature thermometers was developed.Contin...Based on the analysis and investigation of calibration systems for high-accuracy low temperature thermometers,a new facility for automatic calibration of high-accuracy low temperature thermometers was developed.Continuous calibration for multiple points can be made automatically with this device.According to the thermophysical characteristics of the constant-temperature block in this device,segmented Fuzzy-PID (proportional-integral-differential) algorithm was applied.The experimental results showed that the temperature fluctuation was smaller than ±0.005 K in 30 min.Therefore,this new device can fully meet the calibration requirement of high-precision low temperature thermometers.展开更多
基金Project(61174132)supported by the National Natural Science Foundation of ChinaProject(2015zzts047)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(20130162110067)supported by the Research Fund for the Doctoral Program of Higher Education of China
文摘The temperature control of the large-scale vertical quench furnace is very difficult due to its huge volume and complex thermal exchanges. To meet the technical requirement of the quenching process, a temperature control system which integrates temperature calibration and temperature uniformity control is developed for the thermal treatment of aluminum alloy workpieces in the large-scale vertical quench furnace. To obtain the aluminum alloy workpiece temperature, an air heat transfer model is newly established to describe the temperature gradient distribution so that the immeasurable workpiece temperature can be calibrated from the available thermocouple temperature. To satisfy the uniformity control of the furnace temperature, a second order partial differential equation(PDE) is derived to describe the thermal dynamics inside the vertical quench furnace. Based on the PDE, a decoupling matrix is constructed to solve the coupling issue and decouple the heating process into multiple independent heating subsystems. Then, using the expert control rule to find a compromise of temperature rising time and overshoot during the quenching process. The developed temperature control system has been successfully applied to a 31 m large-scale vertical quench furnace, and the industrial running results show the significant improvement of the temperature uniformity, lower overshoot and shortened processing time.
基金supported by the National Basic Research Program of China (Grant No. 2010CB227304)the Major Program of the National Natural Science Foundation of China (Grant No. 50890184)
文摘Based on the analysis and investigation of calibration systems for high-accuracy low temperature thermometers,a new facility for automatic calibration of high-accuracy low temperature thermometers was developed.Continuous calibration for multiple points can be made automatically with this device.According to the thermophysical characteristics of the constant-temperature block in this device,segmented Fuzzy-PID (proportional-integral-differential) algorithm was applied.The experimental results showed that the temperature fluctuation was smaller than ±0.005 K in 30 min.Therefore,this new device can fully meet the calibration requirement of high-precision low temperature thermometers.
