水平管内两相流动网丝电容层析成像

Wire-Mesh Capacitance Tomography of Two-Phase Flows in a Horizontal Tube

提出一种两相流相分布的网丝电容层析成像方法。应用表面带有绝缘膜的热偶丝作为电容传感器,电容的电介质为绝缘膜,两极分别为热偶丝的金属芯和覆盖在热偶丝表面的导电液膜。电容与导电液膜长度成正比,与导电液膜分布和形状无关,网丝平行均匀布置在管道截面上。实验管道内径70 mm,所用网丝每毫米电容值为4.82 pF,网丝间距4mm。利用水平和竖直二方向电容传感器进行测量,根据流型知识,无需重建算法即可得出相分布。静态试验表明,该方法能实现流型重建,计算得到的截面含水率误差最大为3.9%。

A wire-mesh capacitance tomography of two-phase flow distribution is presented.Thermocouple wires with an insulation film on their surface are used as capacitive transducers.The electrolyte of the capacitor is an insulation film with the two poles being respectively metal cores of thermocouple wires and electroconductive fluid film covering the surface of thermocouple wires.The capacitance is directly proportional to the length of the electroconductive fluid film and independent of the latter's distribution and shape.The wire-meshes are parallel and uniformly arranged on a pipeline section.The inner diameter of the test pipeline is 70 mm and the capacitance of each mm long mesh wire being used is 4.82 pF with the spacing of mesh wires being 4 mm.The measurement was performed by use of horizontal and vertical two-direction capacitive transducers.On the basis of knowledge about flow patterns,it is not necessary to reestablish algorithm and the phase distribution can be readily obtained.The steady-state tests show that with this method one can realize the reestablishment of flow patterns,and the section water content as calculated based on the foregoing has a maximal error of 3.9%.