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氧浓度分析仪被广泛地用于各行各业中,热磁对流氧浓度传感器具有使用寿命长、测量准确度高等优点.它巧妙地利用热磁对流现象引起传感器壁面温度的变化来感知氧气浓度的变化.但是由于热磁对流现象较为复杂,其感应机理尚不明确,为了进一步提高热磁对流氧浓度传感器的测量精度,有必要对其感应机理深入研究.本文通过实验的方法研究了两块方形磁铁构成的非均匀磁场作用下薄壁圆管中顺磁性气体在其中的传热特性.实验结果表明:圆管壁面温度在磁场的作用下较无磁场时有明显的降低,且随着热流密度的增大,管壁温度降低得越明显,管壁温度与热流密度成线性关系;随着热流密度的增大,热磁对流现象引起的平均速度及对流换热系数均增大;氧气浓度每增加10%,管壁温差降低0.12℃,即氧气浓度越高热磁对流现象越明显;所研究系统对于氧气浓度的分辨率约可达0.08%.
Oxygen analyzer is widely used in all walks of life, thermal convection oxygen concentration sensor has the advantages of long service life, high measurement accuracy. It clever use of magnetic convection phenomenon caused by changes in sensor wall temperature to sense the oxygen concentration However, due to the complex phenomenon of thermal convection, the sensing mechanism is not clear, in order to further improve the measurement accuracy of the sensor, it is necessary to study its sensing mechanism.In this paper, two square And the heat transfer characteristics of the paramagnetic gas in the thin-walled circular tube under the non-uniform magnetic field of the magnet.The experimental results show that the temperature of the wall of the circular tube decreases obviously under the action of the magnetic field compared with the non-magnetic field, The temperature of tube wall decreases linearly with the heat flux density. With the increase of heat flux density, the average velocity and the convection heat transfer coefficient caused by the convection phenomenon increase. When the oxygen concentration increases by 10 %, The temperature difference between the pipe wall decreases by 0.12 ℃, that is, the higher the oxygen concentration, the more obvious the phenomenon of the thermal convection; the resolution of the studied system for the oxygen concentration is about Up to 0.08%.