流化床埋管表面局部空隙率测试装置的研制

An Instrument for Measuring the Local Porosity around the Tube Surface Buried in a Fluidized Bed

1 基本原理对于换热表面附近的气固两相运动情况,即使采用内窥镜、光导纤维、X射线等先进技术,也仅能定性地观察气固两相运动情况.为了进一步研究床内埋设表面的换热机理,了解表面附近气固两相运动情况,本文研制了能从一定程度上反映气固两相运动的换热表面局部瞬态空隙率的测量装置.在流化床内埋设换热表面上嵌入两个电容极片,换热表面附近气体和固体颗粒则是电容器的电介质.任意两个相隔一定距离的导体都可以构成一个电容器.在导体的几何形状与位置确定后,其电容量只与其周围电介质的介电常数ε_e有关。

An instrument for measuring the local porosity around the surface of the tube buried in a fluidized bed has been developed. With the probe fixed inside the tube, the measuring accuracy of the instrument is almost free of the interference of stray parameters.The circuit and structure are simple. There is no interference from the probe with the flow field and the dynamic characteristic of the probe is just fine. The instrument is useful for studies of the mechanism of the flow and heat transfer in a fluidized bed.