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A horizontal dilute-phase pneumatic conveying system using vertically oscillating soft fins at the inlet of the gas–particle mixture was studied to reduce the power consumption and conveying velocity in the conveying process. The effect of different fin lengths on horizontal pneumatic conveying was studied in terms of the pressure drop, conveying velocity, power consumption, particle velocity, and intensity of particle fluctuation velocity for the case of a low solid mass flow rate. The conveying pipeline consisted of a horizontal smooth acrylic tube with an inner diameter of 80 mm and a length of approximately 5 m. Two types of polyethylene particles with diameters of 2.3 and 3.3 mm were used as conveying materials. The superficial air velocity was varied from 10 to 17 m/s, and the solid mass flow rates were 0.25 and 0.20 kg/s. Compared with conventional pneumatic conveying, the pressure drop, MPD (minimum pressure drop), critical velocities, and power consumption can be reduced by using soft fins in a lower air velocity range, and the efficiency of fins becomes more evident when increasing the length of fins or touching particles stream by the long fins. The maximum reduction rates of the MPD velocity and power consumption when using soft fins are approximately 15% and 26%, respectively. The magnitude of the vertical particle velocity for different lengths of fins is clearly lower than that of the vertical particle velocity for a non-fin conveying system near the bottom of the pipeline, indicating that the particles are easily suspended. The intensities of particle fluctuation velocity of using fins are larger than that of non-fin. The high particle fluctuation energy implies that particles are easily suspended and are easily conveyed and accelerated. [ABSTRACT FROM PUBLISHER]

In order to reduce pressure drop and conveying air velocity, the paper studied the effect of the dune model and soft fins in horizontal pneumatic conveying involving a 90° bend. Experimental measurements were performed in terms of the pressure drop, conveying air velocity and additional pressure drop. The distributions of particle velocity near and in the curved 90° bend were measured by high-speed PIV. The test pipeline consisted of a 4.5m-long horizontal straight acrylic tube, a curved 90° acrylic bend (mean radius of curvature 250mm) and a 1.5m-long horizontal straight acrylic tube, having an inside diameter of 80mm. The polyethylene particles with diameter of 2.3mm were used as conveying materials. The superficial air velocity was varied from 10 to 14m/s, and the solid mass flow rate was fixed at 0.45kg/s. Comparing with the conventional pneumatic conveying, the pressure drop, the minimum pressure drop (MPD) velocity and additional pressure drop can be reduced by using soft fins in lower air velocity range. The reduction rates of the MPD velocity by using soft fins and dune model were about 4.1% and 8.3%, respectively. At the upstream of bend and in the bend, the particle velocity of using the dune model is evidently higher than that of the conventional pneumatic conveying and using soft fins. However, the effect of soft fins and dune model on the particle velocity is maintained downstream of the bend. [ABSTRACT FROM AUTHOR]