Experimental study on acoustic vector tomography of 2-D flow field in an experiment-scale furnace

An experiment study is performed on acoustic measurement of 2-D dynamic fields in a cold experimental scale furnace. By the acoustic method, the velocity field is restored with the vector tomography from the reciprocal acoustic travel time data measured. Regarding the measuring system, piezoelectric speakers and pickups are used as transmitters and receivers, which can stimulate powerful acoustic signal resource and receive the acoustic signal stimulated from long distance respectively. A high-pass digital FIR filter is designed for the signal filtering, and the signal correlation analysis by correlation coefficient is performed to obtain accurate acoustic transit time data from the filtered simulated and received acoustic signals. In the experiments, two different cases are tested, respectively symmetric and asymmetric flow fields. To validate the flow field recovered by the acoustic method, under the same conditions, the symmetric velocity field is measured by a hot-wire anemometer at some points and simulated with CFD software, and the asymmetrical velocity field is simulated. It is proved that the flow fields recovered by the acoustic method are reasonable and reliable. As a whole, from the experiment results, the acoustic measuring system and method developed in this paper is applicable in measuring the 2-D flow field in a cold experimental set-up and similarly in cold large-scale industrial furnaces. Additionally, the extension of the method to hot furnaces is discussed too.