The Experiment Study Of The Thermal Magnetic Type Oxygen Sensor

The oxygen sensor is widely used in all walks of life, the thermal magnetic type oxygen sensor has developed vigorously due to its unique advantages. Thermal magnetic type oxygen sensor has some advantages such as losses, long service life and high accuracy of measurement. There have been the related products at home and abroad, which take skillfully advantage of the thermal magnetic convection phenomenon gives rise to the changes with the wall temperature to sense the change of oxygen concentration. However, the thermal magnetic convection phenomenon is complicated, whose heat transfer mechanism is not clear, therefore it is necessary to research the perception mechanism in-depth to improve the thermal magnetic type oxygen sensor measurement accuracy.This paper, by means of experiments, studies the heat transfer characteristics of paramagnetic gas in the thin-walled circular tube in a non-uniform magnetic field from the two pieces of rectangular magnets, and the result have good consistency comparing with the numerical simulation. In magnetic field, the surface temperature of tube wall has significantly lower comparing with the nonmagnetic field. With the increase of heat flux, the surface temperature of tube wall has significantly lower. It is also found that the relationship of heat flux density and wall temperature is nearly liner.With the increase of heat flux density, the average velocity and convective heat transfer coefficient caused by the thermal magnetic convection phenomenon are increased. But their increase tendency slows down, it means that the best temperature field corresponds to the condition of the magnetic field. High heat flux is not conducive to the stability of experimental system, and needlessly. When oxygen content is increasing 10%, the temperature of tube wall has decreased about 0.12 ℃. In other word, the higher oxygen concentration is, the more obvious about convective heat transfer phenomenon is. The resolution of oxygen concentration experiment system is about 0.08%.