Abstract：The dune model was mounted on the bottom of conveying pipe near the inlet of particle feed for the problem of energy loss serious in pneumatic conveying to study the minimum pressure and minimum conveying velocity. To reveal the mechanism of the low conveying velocity and saving-energy conveying with dune model, PIV (particle image velocimetry) technology was developed to measure and analyze the time-averaged particle velocity and particle fluctuation velocity for all cases in the acceleration region. The study focuses on the effect of the different locations of dune model on the horizontal pneumatic conveying in terms of the time-averaged particle velocity, power spectrum, autocorrelation coefficients, two-point correlation coefficients and fluctuation intensity of particle velocity. It is found that the time-averaged particle velocity and power spectra peaks of particle fluctuation velocity are higher than that of non-dune on the same air velocity for all cases, and the auto-correlation coefficients of particle fluctuation velocity display a quasi-periodical wave. Meanwhile, the two-point correlation coefficients of particle fluctuation velocity and fluctuation intensity of particle velocity is larger than that of non-dune.

Keywords：pneumatic conveying; PIV; minimum conveying velocity; particle fluctuation velocity; power spectrum