Signal processing and analysis applied to powder behavior in a rotating drum

Previous studies of the flow of granular materials in a rotating drum have described the observed time sequences of angle of repose or time to avalanc he. The time between avalanches approach has been incorporated into a comme rcially available powder flow analysis tool. In the present study, the time to avalanche analysis was complemented with a Fourier Transform power spec trum and phase space analysis of the angle of repose time series and avalan che size variability determination. The avalanche size variability approach was found to most readily differentiate between the flow properties of pow ders across material types. A model was constructed to provide an explanati on for the utility of this method.