用于两相流流型显示和空隙率测量的电容层析成像技术

引　言两相流流型的实时显示和空隙率的在线测量对两相流系统的控制、运行乃至机理研究等均具有重要意义 ,一直是两相流领域中重要的研究方向 .现已提出多种实现流型显示和空隙率测量的方法 ,例如用于流型显示的核辐射线法和光学法 ,用于空隙率 (或浓度 )测量的机理估算法、核辐射线法、电学法、光学法、微波法、热学法和核磁共振法等 ,但是总的来讲还未能满足应用要求 ,实际应用的例子也较少[1] .电容层析成像 (ｅｌｅｃｔｒｉｃａｌｃａｐａｃｉｔａｎｃｅｔｏｍｏｇｒａｐｈｙ ,简记ＥＣＴ)技术由于可在不干扰流场的情况下获取反映两相流…

APPLICATIONS OF ELECTRICAL CAPACITANCE TOMOGRAPHY TECHNIQUE TO FLOW PATTERN DISPLAY AND VOIDAGE MEASUREMENT OF TWO-PHASE FLOW

Based on electrical capacitance tomography technique, a novel method for flow pattern display and voidage measurement of two-phase flow was proposed. A 12-electrode ECT measurement system was developed. The weighted back projection algorithm was selected as the image reconstruction algorithm to satisfy the requirement of flow pattern display. Combining the principle of Tikhnov regularization theory with the ART(Algebraic Reconstruction Technique) algorithm, a new quantitative image reconstruction algorithm was developed to implement voidage measurement of two-phase flow. Experimental results of gas-liqiud two-phase flow and gas-solid fluidized bed showed that the developed measurement system was successful. The speed of image reconstruction of flow pattern display was greater than 20 frames per second. The maximum error of voidage measurement is less than 5% and the time of voidage measurement is less than 2 seconds.