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ABSTRACT
A predictive two-phase CFD model requiring no experimental input is used to estimate dispersed phase holdup in a pulsed sieve plate column (PSPC). Drop diameter used in simulations is obtained from a reported correlation. Reported experimental data are used for validation. Average error in estimated values of dispersed phase holdup is about 17% when standard Kumar–Hartland drag model is used. The average error is reduced to about 6% by modifying the drag model. Efficacy of the CFD model embedding the modified drag model is tested with the reported experimental data of PSPCs having different geometries, operated with different phase systems.
Nomenclature
| A | = | Empirical constant used in Kumar-Hartland model [-] |
| Am | = | Pulse amplitude [L] |
| B | = | Empirical constant used in Kumar-Hartland model[-] |
| C1ε, C2ε, Cµ | = | Constants in standard k-ε model [-] |
| CD | = | Drag coefficient [-] |
| dh | = | Sieve plate hole diameter [L] |
| dp | = | Drop diameter [L] |
| d32 | = | Sauter mean diameter [L] |
| f | = | Pulse frequency [1/T] |
| g | = | Acceleration due to gravity [L/T2] |
| Gk,m | = | Rate of production of turbulent kinetic energy [M/LT3] |
| h | = | Plate spacing [L] |
| k | = | Turbulent kinetic energy [L2/T2] |
| Kij | = | Interphase momentum exchange coefficient [-] |
| = | Volumetric interphase exchange force [M/L2T2] | |
| Re | = | Drop Reynolds number [-] |
| p | = | Static pressure [M/LT2] |
| = | Velocity vector [L/T] | |
| vd | = | Dispersed phase superficial velocity [L/T] |
| vc | = | Continuous phase superficial velocity [L/T] |
| Vslip | = | Slip velocity [L/T] |
Greek Letters
| α | = | Volume fraction of ith phase [-] |
| β | = | Fractional open area of the plate [-] |
| Δρ | = | Density difference between two phases [M/L3] |
| ε | = | Turbulent energy dissipation rate [L2/T3] |
| µ | = | viscosity [M/LT] |
| = | Dispersed phase holdup [-] | |
| ρ | = | Density [M/L3] |
| σ | = | Interfacial tension [M/T2] |
| = | Stress tensor [M/LT2] |
Subscript
| c | = | Continuous phase |
| d | = | Dispersed phase |
| i | = | ith phase in multiphase flow |
| i.lam | = | ith phase, viscous |
| i.tur | = | ith phase, turbulent |
| m | = | Mixed phase in multiphase flow |
| t | = | turbulent |