A temperature control system of 31m vertical forced air-circulation quench furnace is proposed, which is a kind of equipment critical for thermal treatment of aluminum alloy components that are widely used in aerospac...A temperature control system of 31m vertical forced air-circulation quench furnace is proposed, which is a kind of equipment critical for thermal treatment of aluminum alloy components that are widely used in aerospace industry. For the effective operation of the furnace, it is essential to analyze the radial temperature distribution of the furnace. A set of thermodynamic balance equations modeling is established firsdy. By utilizing the numerical analysis result to modify the temperature measurements, the control accuracy and precision of the temperature are truly guaranteed. Furthermore, the multivariable decoupling self-learning PID control algorithm based on the characteristics of strong coupling between the multi-zones in the large-scaled furnace is implemented to ensure the true homogeneity of the axial temperature distribution. Finally, the redundant structure composed of industrial control computers and touch panels leads to great improvement of system reliability.展开更多
An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and...An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and 45°. The results of the temperature profile across the air gap showed that heat transfer from the absorber plate to the air stream was mainly by convection. At a particular section, mean air temperature could be calculated from the arithmetic mean of the temperature profile across the air gap to within ± 2 ℃. The axial air temperature distribution was non linear and did not increase much beyond 1 m of collector length. It tended to decrease towards the end of the collector. Overall glass, absorber plate and mean air temperatures over the entire length of the solar air heater could be determined by averaging the mean axial temperatures to within ± 2 ℃. The heater performed better as inclination increased.展开更多
基金It was supported by the National Natural Science Foundation of China (No. 59835170).
文摘A temperature control system of 31m vertical forced air-circulation quench furnace is proposed, which is a kind of equipment critical for thermal treatment of aluminum alloy components that are widely used in aerospace industry. For the effective operation of the furnace, it is essential to analyze the radial temperature distribution of the furnace. A set of thermodynamic balance equations modeling is established firsdy. By utilizing the numerical analysis result to modify the temperature measurements, the control accuracy and precision of the temperature are truly guaranteed. Furthermore, the multivariable decoupling self-learning PID control algorithm based on the characteristics of strong coupling between the multi-zones in the large-scaled furnace is implemented to ensure the true homogeneity of the axial temperature distribution. Finally, the redundant structure composed of industrial control computers and touch panels leads to great improvement of system reliability.
文摘An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and 45°. The results of the temperature profile across the air gap showed that heat transfer from the absorber plate to the air stream was mainly by convection. At a particular section, mean air temperature could be calculated from the arithmetic mean of the temperature profile across the air gap to within ± 2 ℃. The axial air temperature distribution was non linear and did not increase much beyond 1 m of collector length. It tended to decrease towards the end of the collector. Overall glass, absorber plate and mean air temperatures over the entire length of the solar air heater could be determined by averaging the mean axial temperatures to within ± 2 ℃. The heater performed better as inclination increased.
