Using Principal Component Analysis

to Measure Two-Phase Flow Concentration

Lu Zou, Yuchun Zhang, Danya Yao, Lihui Peng, Baofen Zhang Department of Automation, Tsinghua University, Beijing, 100084, P.R.China
Email: zbf-dau@mail.tsinghua.edu.cn

ABSTRACT

Concentration profile of two-phase flow can be measured by using electrical capacitance tomography (ECT). However, for the ill-posedness and non-linearity of ECT, concentration profile according to reconstructed image is of low quality. In this paper, the technique known as principal component analysis (PCA) is used to provide a more flexible strategy to measure the concentration profile. It is found that the first principal component from ECT capacitance measurements is consistent with the concentration. An empirical equation has been obtained through data fitting and it gives an estimation of phase concentration whose error is within 5%. Several sets of experiments have been carried out to test the validity of this new method and the results are compared with those based on image reconstruction. It is concluded that PCA is capable of giving a satisfying estimation of phase concentration of two-phase flow.

Keywords two-phase flow, concentration, PCA, ECT