Experimental Investigation of Spout Deflection in a Rectangular Spouted Bed by the PIV Method

Abstract

Spout deflection is a common instability phenomenon, which has been widely encountered in spouted and spout-fluidized beds. However, the spout deflection has not been quantified experimentally. In the present work, the alternating spout deflection behavior is captured by employing the particle image velocimetry (PIV) method and quantified based on PIV vector fields over a wide range of variables in terms of bed heights and spouting velocities. The results show that the static bed height has an obvious effect on the alternating spout deflection. The amplitude of the alternating spout deflection keeps stable at first and then reduces quickly with increasing static bed height. The drop tendency is ascribed to the appearance of spout incoherence behavior in which the particle blockage periodically forms and explodes in the spout region. This explosion contributes to uniform particle spurting and reduces the height difference between two annulus regions and the spout deflection amplitude. The amplitude of the alternating spout deflection is stable with increasing spouting velocity, which can be owed to the self-locking phenomenon. Specifically, the particles in the annulus region on one side cannot be transported away due to the resistance of the deflected spout and thereby preventing the further deflection of the spout. Spouting velocity has a neglectable influence on the regularity and main frequency of the alternating spout deflection. This work unveils the hydrodynamics of spout deflection and provides a methodology for experimental investigation of spout deflection in spouted beds.

Toward High-Order CFD-DEM: Development and Validation

“…We simulate a rectangular spouted bed. We calculate the time averaged particles’ velocities at different positions in the bed and compare the data obtained with experimental results obtained using particle image velocimetry …”

“…The authors did not specify the number of particles used but they specified the static bed height to be 200 mm. Based on the given geometry, and in order to obtain a similar static bed height, we use 175 800 particles with the same properties as those used by Yue et al 65 The particles used in this test case belong to the Geldart D group. In order to obtain better distribution of the flow and stability of the solver, we add to the geometry a small channel at the bottom of the bed through which we introduce the gas.…”

“…Results and Discussion. For both Q1-Q1 and Q2-Q1 simulations, we measure the time averaged particle velocity profile in the direction of the flow at different heights (y-axis) of the bed and we compare the values with the experimental results of Yue et al 65 The results obtained using both the PCM and SPM void fraction schemes are presented. The heights in Figures 11 and 12 are normalized by the static bed height.…”

“…We calculate the time averaged particles' velocities at different positions in the bed and compare the data obtained with experimental results obtained using particle image velocimetry. 65 Simulation Setup. The bed size, geometry, and solid and fluid properties are extracted from the experiment of Yue et al 65 Figure 10 shows the schematic geometry of the simulation.…”

Optimization of the Tracer Particle Addition Method for PIV Flowmeters

“…In this type of experiment, it is necessary to form a complete set of equipment placed around the transparent pipes, which can then be measured. This method possesses the advantages of convenient installation and simple operation because it is based on tracer particles of the pulsed laser refractive reaction flow field characteristics, making it less sensitive to outside interference; furthermore, the accuracy of PIV testing of the flow field has been thoroughly experimentally validated [14][15][16]. Therefore, the application of PIV technology in large flow metering of natural gas has the advantages of convenient installation and use, strong anti-noise ability and long service life.…”