Transport Phenomena,
A.R. bahramian
Abstract
The impact of bed loading on minimum spouting velocity (ums) of polydispersed TiO2 particles was studied in a conical fluidized bed. The experiments were performed at different bed loadings according to Gaussian and narrow-cut particle size distribution (PSD). The bed consisted of simple-agglomerates ...
Read More
The impact of bed loading on minimum spouting velocity (ums) of polydispersed TiO2 particles was studied in a conical fluidized bed. The experiments were performed at different bed loadings according to Gaussian and narrow-cut particle size distribution (PSD). The bed consisted of simple-agglomerates in size range of 30-90 µm belonging to Geldarts’ group A classification. The effect of PSD and interparticle force (IPF) on the predicted ums and hysteresis in the pressure profiles were studied through a combination of computational fluid dynamics and discrete element method (CFD-DEM). The experimental data showed that the choice of bed with Gaussian PSD-type led to more accurately predicting ums than the narrow-cut particle PSD. The impact of IPF on the expected ums became more critical than the PSD type because of an increase in bed loadings. The lowest deviations the results were obtained in the low bed loadings, which is confirmed the accuracy of simulation results. The simultaneous effects of PSD-type and IPF led to a change in the fluidization behavior of the bed. The bed with narrow-cut PSD has a hydrodynamic behavior similar to spouting and slugging regimes, while the fluidization quality of the bed improves by fine particles.
Transport Phenomena,
H. Hoorijani; R. Zarghami; N. Mostoufi
Abstract
The effect of adding isopropanol (ISP) to nitrogen as the fluidizing gas on the hydrodynamics of the fluidization of hydrophilic titanium nanoparticles was studied. It was shown by the pressure drop method that adding ISP reduces the minimum fluidization velocity. Wavelet transform of the pressure fluctuations ...
Read More
The effect of adding isopropanol (ISP) to nitrogen as the fluidizing gas on the hydrodynamics of the fluidization of hydrophilic titanium nanoparticles was studied. It was shown by the pressure drop method that adding ISP reduces the minimum fluidization velocity. Wavelet transform of the pressure fluctuations of the bed was employed to identify the hydrodynamic structures. The energy of hydrodynamic structures was evaluated in each fluidization mode. It was shown that ISP reduces the inter-particle attractive forces by replacing the hydroxyl group of the hydrophilic nanoparticles with an alkyl group. Energy and recurrence analyses were used to define the characteristics of fluidization when adding ISP to nitrogen gas. The energy of macro structures increased when using ISP, having indicated a decrease in the number of bubbles and an increase in the bubble size due to the reduction of inter-particle attractive forces. The increase of the white local areas in the recurrence plots also showed the increase of the bubble size. The recurrence quantification analysis showed the increase of the larger-scale phenomena (i.e. bubbles) in the bed.