https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:32957 -5 to 5 × 10^-4 m2 s^-1 when energy dissipation rate increased from ~ 0.005-0.01 m² s^-3. Different dispersion correlations were then utilized to describe the intermixing and segregation behaviour for the binary particle species differing in density in terms of axial particle concentration profile using a one-dimensional convection-diffusion model which agreed well with the experimental data. Additionally, a two-dimensional (2D) Eulerian-Eulerian (E-E) model based on kinetic theory of granular flow (KTGF) was used to simulate axial variation of the binary solids concentration which showed good agreement (~ 10% deviation) with the published experimental data. Axial profile of dispersion coefficient predicted by the various correlations exhibited a sharp variation in the intermixing zone formed in between the lower (higher density) and upper particle bed (low density). In this region, CFD model predicted energy dissipation rate increased significantly with liquid superficial velocity which reflected strong phase interactions in the intermixing zone.]]> Thu 16 Aug 2018 13:36:10 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:32954 f₁, has been proposed (see for example Joshi et al. (2001)). Briefly, the LSA analysis utilises the velocity fluctuations of both the dispersed and continuous phases associated with the specific energy dissipation rate of the two phase mixture. Typically, the specific energy dissipation rate is correlated with the density of the bed. The previous analysis, however, does not consider the energy input which associated with the turbulence intensity (velocity fluctuations) of the incoming liquid stream. Usually, this component can be ignored in sparged bubble columns because its magnitude is relatively small and it also decays in the axial direction. In plunging liquid jet bubble columns the liquid is introduced as a high speed jet that entrains gas which is then broken into fine bubbles in the Mixing Zone. The bubby mixture then passes into the Two Phase Flow Zone where instabilities can be generated. The Mixing Zone is a region of high energy dissipation resulting in relatively large liquid velocity fluctuations, which can directly influence the instability of the Two Phase Flow Zone. In this study the existing linear stability analysis is modified to include the influence of inlet liquid velocity fluctuations on the stability parameter, f₁. The modified theory is applied to the previous work of Evans (1990) for a plunging liquid jet bubble column to determine the critical gas volume fraction at which transition takes place in the Two Phase Flow Zone. In order to apply the model, drift-flux analysis has been used to obtain bubble diameter as a function of gas and liquid superficial velocities, and computational fluid dynamics has been utilised to quantify the velocity fluctuations of the liquid exiting the Mixing Zone.]]> Thu 16 Aug 2018 13:36:04 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:32955 Thu 16 Aug 2018 13:35:45 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20228 −3 m) and terminal rise velocity (80–340 × 10⁻³ m/s), particle settling velocity (1–1000 × 10⁻³ m/s), particle concentration (0.0007–30 vol%) and slurry density (800–5000 kg/m³). It was observed that the developed model predicts the transition gas holdup within an absolute deviation of 12% for three-phase sparged reactors. It was also observed that the developed generalized stability criterion predicts the regime transition in two-phase systems satisfactorily when applied to bubble columns.]]> Sat 24 Mar 2018 08:06:49 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20915 Sat 24 Mar 2018 08:06:12 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20600 P2/d_P1) and became independent of the foreign particle size for high solid fractions when the fluidised particle size was kept constant. The magnitude of collision force was 10-50 times greater than that of gravitational force and maximally 9 times greater than that of drag force. A correlation describing the collision force as a function of bed voidage was developed for St_p>65 and d_P2/d_P1≤2. A maximum deviation of less than 20% was obtained when the correlation was used for the prediction of particle collision force.]]> Sat 24 Mar 2018 07:55:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:28747 d_PD=5–12 mm) and single air bubbles (d_B=1–4 mm) has been measured in a solid–liquid fluidized bed of uniform size borosilicate glass beads (d_P=5 and 8 mm) as a function of liquid superficial velocity. The homogeneity and intensity of the turbulence within the fluidized bed has been quantified and directly related to the slip velocity of the foreign (steel or bubble) particle. It was found that the turbulence resulted in an increase in the computed drag coefficient for all of the experimental conditions investigated.]]> Sat 24 Mar 2018 07:37:35 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26431 Sat 24 Mar 2018 07:27:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25528 -3) were used as fluidised particles. Three different combinations of particle size pairs of both equal and unequal mass ratios were used using a constant liquid (water) superficial velocity of 0.17 ms^-1 in all the cases. Numerically, a two dimensional Eulerian-Eulerian (E-E) CFD model incorporating kinetic theory of granular flow (KTGF) was developed to predict the bed expansion behaviour. It was observed that complete bed segregation occurred when the difference between the solid particle diameters was higher while lower difference in particle diameters led to partial bed segregation. The CFD model also predicted these behaviours which were in good agreement with the experimental data.]]> Sat 24 Mar 2018 07:26:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25529 -3 were fluidised in water. Binary experiments were carried out considering both equal and unequal solid mass ratios ranging from 0.16 to 6.0. The overall bed expansions including segregated and intermixed zones were monitored. The effect of loading pattern on bed expansion was found insignificant in a binary SLFB. In a completely segregated SLFB, bottom mono-component layer displayed a negative deviation up to 30% whereas a positive deviation up to 22% was found in top mono-component layer when compared to respective individual monocomponent SLFBs. The total bed height of binary mixture was found to be unequal to sum of expanded bed height in individual mono-component SLFB, showing either positive or negative deviations. The experimentally observed criterion of the bed independency has been tabulated. Eulerian-Eulerian (E-E) CFD simulations with kinetic theory of granular flow (KTGF) have been performed and compared with the experimental data. The CFD predictions were found to be in good agreement (within ±6 per cent deviation) when compared to experimental results.]]> Sat 24 Mar 2018 07:26:07 AEDT ]]>