Hydrodynamic Characterization of a Shallow Rectangular Spouted Bed Using Bed Pressure Signals and Image Processing Methods

A coupled computational fluid dynamics (CFD)discrete element method (DEM) technique has been adopted to examine the dynamic behavior of particles in a rectangular spouted bed. Eulerian method has been used to solve the Navier−Stokes equation for the gas phase (for the CFD) and Lagrangian method (for the DEM) for the particle phase, where the k−ϵ two-equation turbulence model has been used to capture the effect of gas-phase turbulence. In the present work, we sought to predict the minimum spouting velocity (U ms ) numerically for a fixed bed height and particular particle properties. The effects of the inelastic collision and the friction on translational and rotational dynamics of the particles in spout, annulus, and fountain zones have been brought out with the intensive parametric study. The results reported here would be a way forward for a better understanding of the spouted bed processing where translational and rotational dynamics of particles play a key role.

Section: ■ Introductionmentioning

confidence: 99%

Numerical Studies on Particle Dynamics in a Spouted Bed

Raman

Mollick

Goswami

2021

“…Pressure drop is one of the most critical hydrodynamic parameters for the design and scaleup of spouted beds. , To analyze dryer-bed cross-domain characteristics, the pressure drop curves of different bed heights and gas velocities were measured by experiments, as shown in Figure . It can be observed that the pressure drop for a 50-mm static bed height changes insignificantly, compared to that for static bed heights of 100 mm and 150 mm in Figure a.…”

Section: Resultsmentioning

confidence: 99%

Experimental and Numerical Study of Cross-Domain Hydrodynamics in an Integrated Pneumatic-Spouted Bed

Jiao

Wang

Mei

et al. 2023

As an essential resource, the drying, upgrading, and efficient utilization of lignite are of great significance to the development of the low-carbon economy. In this work, a novel drying system, combining a pneumatic and spouted bed, is designed to achieve lignite deeply dewatering. The system is investigated experimentally and numerical simulated to characterize the hydrodynamics of particles moving across the domain, such as pressure drop, fountain height, and pressure fluctuation. The results show that there is a critical gas velocity that changes the flow pattern of the bed when the static bed is higher than 50 mm. When the gas velocity increases to the critical value, the spouting state becomes unstable and the corresponding pressure drop will undergo a secondary mutation. This work provides a deeper understanding of the flow structure and particle motion in the novel drying system under various industrial operating conditions.

“…7 Despite this, the main challenge for the rectangular spouted bed is the spouting quality. 6 Spout deflection is one of the most typical threats to the spouting quality in the spouted bed in which the spout has both the vertical and lateral movements. This instability phenomenon has been widely reported in many experiments in different names, i.e., the so-called dancing deflection in ref 8, alternative spouting in ref 9, or oscillating deflection in ref 10.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the particle circulation movement at the reactor scale forms. The rectangular spout bed has become increasingly popular due to its viability to be easily scaled up by adding units in the thickness direction or lateral direction . Despite this, the main challenge for the rectangular spouted bed is the spouting quality .…”

Section: Introductionmentioning

confidence: 99%

“…The rectangular spout bed has become increasingly popular due to its viability to be easily scaled up by adding units in the thickness direction or lateral direction . Despite this, the main challenge for the rectangular spouted bed is the spouting quality . Spout deflection is one of the most typical threats to the spouting quality in the spouted bed in which the spout has both the vertical and lateral movements.…”

Section: Introductionmentioning

confidence: 99%

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

Yue

Wang

Bahl

et al. 2020

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.