Transient characteristics of fine powder flows within fluidized dense phase pneumatic conveying systems

The objective of this paper is to report the experimental findings related to the pressure fluctuations in the fluidized dense phase pneumatic conveying of fine powders in the pipeline. Investigation has also been carried out to understand the relation between pressure pulse characteristics and specific power consumption and pneumatic conveying parameters. In addition, the transition in mode of flow along the downstream of flow of fine powders has been assessed and discussed. The wavelet analysis (Daubechies db4 wavelet) of signals of air pulses revealed that the moving bed flow possesses the transient feature and pulsatile phenomenon characterized by multiple amplitudes and random frequencies. Variations of pulse structures along the length of pipeline have been observed due to occurring of frequent aeration and de-aeration of dunes during the conveying. Substantial variations in pulse structures have also been found with different types of bulk materials. Pulse velocities of air between two data points are found higher at high solid loading ratios leading to low voidage in case of dense phase flow.