Measurement of mixing time in a gas-liquid mixing system stirred by top-blown air using ECT and image analysis

Abstract

The non-invasive acquisition of mixing state quality of the gas-liquid two-phase flow stirred by top-blown air (GTFSTA) is one of the difficulties in studying Isa reactor used for copper smelting. With the help of electrical capacitance tomography (ECT)-based visualization experiments, in this work, a powerful and effectively hybrid strategy is proposed to measure the mixing state quality of the GTFSTA. Specifically, the GTFSTA with thermal condition is successfully visualized by an ECT-based measurement system. After chaos detection by the three-state test (3ST) method, the mixing time of GTFSTA system under hot state is accurately estimated by Logistic regression method for the first time. Experimental and calculated results show that ECT can be used to visualize the flow pattern of which accuracy reaches 98.69%. The case or working condition (Q =2.0 m3/h, H = 30 cm and T = 45 °C) reaches the mixing state with the mixing time 6.5 s, and the best state of the gas-liquid mixing system is chaotic. The new method can well characterize the flow state in the GTFSTA system and can provide theoretical basis for the actual production process. It not only enriches the analysis method of ECT measurement data, but also creates conditions for the engineering application of online detection system based on ECT data.