关键词: 电加热锅炉, 温控器, 干烧, 静态, 动态, 数值模拟, NTC感温元件

Abstract: In view of the risks of thermostat meltdown and excessive temperature on the surface of the electrically heated boiler during dry burning, as well as the problem that the water temperature near the NTC temperature sensing element and the water temperature at the outlet may be too different when the boiler is boiling water, a coffee electromechanical heated boiler is taken as an example, and the shell wall temperature and the water temperature at the outlet are numerically simulated under dry burning, static conditions and dynamic conditions, respectively. The accuracy of the numerical model is verified by experimental tests. The results show that under dry burning condition, the temperature rise rate of the shell wall gradually accelerates and the temperature reaches 150℃ after 92 seconds of heating. Under static and dynamic conditions, the boiler water temperature continues to rise and then declines, finally reaches the dynamic equilibrium state, with the temperature stabilizing at about 67℃. Through comparative analysis, the maximum relative error between the simulated value and the experimental value is less than 5%, which indicates that the numerical model has high accuracy and can be used as a reference for the design of the boiler automatic control system.

Key words: Electrically heated boiler, Thermostat, Dry burning, Static condition, Dynamic condition, Numerical simulation, NTC temperature sensing element