Development of Simulation Method for Multiphase Flows : Application to Gas-Liquid and Gas-Solid Two Phase Flows Sumitomo Chemical Co., Ltd. Process & Production Technology Center Naoki SHIMADA Tomonari KOBAYASHI Tetsuya SUZUTA We have several processes consisting of mixture of gas, liquid and solid, known as multiphase flow processes, in chemical engineering. In this paper, the simulation method used to deal with such processes in our company has been introduced. Following are examples of some applications, (1) Simulation of liquid mixing in a bubble column, (2) DEM-CFD coupling simulation for fluidized bed with small particles, (3) Simulation of single bubble and droplet by using interface tracking type method. Fig. 1 1) Fig. 2 Tomiyama 2) 1 2 3 (3) Averaging model Spatial resolution Availability of practical problem a int Low High Volume fraction Information of interface Gas Liquid Solid Two-phase flow (2) Particle tracking model Gas Gas (a) Bubble column (b) Fluidized bed Fig. 1 Multiphase flow reactors 1) Continuous flow Motion of Particles (1) Interface tracking model Fig. 2 Reconstruction High Low Classification of computational multiphase fluid dynamics 212
1 2 3 13 DEM-CFD DEM Discrete-Element MethodCFD Computational Fluid Dynamics A R S Fig. 3 a b c AR d 2 8 R Selectivity of R (a) Piston Flow 1.8.6.4.2 2% 8% high conversion low conversion (c) Non-uniform flow.2.4.6.8 1 Conversion of A (d) Comparison of yield (b) Perfectly mixed flow Piston flow Perfectly mixed flow Non-uniform flow Fig. 3 Effect of liquid mixing on a reaction 3) Outlet Conductance meter Separator Outlet Conductance meter Separator D =.3 m Air D =.3 m H=1 m Air Sparger H=1 m Tracer tank Tracer tank Air Chamber Air Chamber Liquid feed tank Pump Liquid inlet φ 75mm Gas hole φ 1mm Liquid feed tank Pump 25mm (a) Bubble column with perforated plate 8 holes, φ 1mm (b) Bubble column with ring sparger Fig. 4 Schematic of apparatus 3) 212
Fig. 4 Fig. 5 C EL C C 2 C +U L = E L (1) t z z 2 tul z EL Fig. 6 2 NP2N+2 -field Model NP2 Fig. 7 a EL bγ EL EL [m 2 /s].8.6.4.2 D=1cm -Exp.(Aoyama et al., Porous plates) D=2cm -Exp.(Aoyama et al., Perforated plate) D=3cm -Exp.(This work, Perforated plate) D=3cm -Exp.(This work, Ring sparger) Towell and Ackermann (1972) Deckwer (1974) Hikita and Kikukawa (1974) Zehner (1986) Fig. 6 Comparison of EL 3) 1 2 1 1 U G [m/s].3m Gas inlet 1.m 1 1 1 Measured Predicted Liquid + tracer (red) EL [m 2 /s] 1 2 1 3 sec 5sec 1sec 15sec 2sec 3sec 5sec (a) Mixing process of tracers (red-colored) 1 4 1 2 3 U G [cm/s] (a) Effect of U G 1..8 1 1 Measured Predicted Dimensionless concentration.6.4.2 EL [m 2 /s] 1 2. 1 2 3 4 time [s] (b) Transient pattern of salinity at the outlet of the column (Concentration is normalized using steady-state value) 1 3.2.4.6.8 1 γ (b) Effect of ratio of upper to total gas flow rate γ Fig. 5 Example of experiments using tracer method 3) Fig. 7 Comparison between simulation and measurement 3) 212
Q upper γ = Q upper + Q lower (2) Qupper Qlower DEM-CFD DEM- CFD DEMCFD DEM F = ma F ma DEM i Fi F i = F G +F C +F D + F AD (3) 1mm k Fig. 8 a Fig. 8 b FAD = Fig. 8 bk 1 k 1 k k FAD GeldartA Fig. 8 c FAD kfad Fig. 9 6μm FGFC FD FADFC Voigt k FC Syringe pump Pressure gauge Glass beads Distributor F c = kx ηẋ (4) (a) Schematic of apparatus xη FD CFD FAD van der Waals 3 kfad 4) k FAD k = 1 N/m 1 N/m 1 1 3 N/m 1 1 4 N/m (b) without adhesion force k = 1 N/m 1 N/m 1 1 3 N/m 1 1 4 N/m (c) with adhesion force Fig. 8 Effect of k on fluidized behavior 4) 212
16 14 Adhesion force (nn) 12 1 8 6 4 2 k = 1 N/m 1 N/m 1 1 3 N/m 7 1 3 N/m Fig. 12 Simulation with dynamic adhesion force 4).1 1 1 1 1 Pre-compression (nn) Fig. 9 Measurement of adhesion force 4) FAD 1nN 4 1 3 FAD 2 FAD k k FAD DEM-CFD 4) Fig. 1 11 ReboundFAD Stickingk FAD Particle v Rebound 4) Fig. 12 k k = 1 N/m k = 7 N/m 7 Front Tracking Level Set Boundary Fitting Coordinate 6) α α 1 v Fig. 1 x = Wall x 2x F AD k Fig. 11 x Sticking Stick/rebound behavior after particle-wall collision 4) Rebound Critical Sticking Particle-wall overlaps in the duration of collision 4) t α +V α = (5) t tv V α 1α α α 2α α α 1 3θ α θ αdθ 4 5Xiao 7) THINC tangent of hyperbola for interface capturing 1 3 212
4 THINC 5) THAINC tangent of hyperbola for adaptive interface capturing Fig. 13 THAINC O O A R R O S O A R S 5 1 4 1 2 1 6 5 1 13 mol/m 3 Fig. 14 8) Fig. 13 O A R S Simulation of dissolution and reaction process with a single bubble 5) Prediction Experiment ms Bubble 1),,, (1999). 2) A. Tomiyama, Proceedings of 3rd International Conference on Multiphase Flow (CD-ROM) (1998). 3) N. Shimada, R. Saiki, A. Dhar, K. Mizuta and A. Tomiyama, Proceedings of 1st International Symposium on Multiscale Multiphase Process Engineering (MMPE) (USB), L-1 (211). 4) T. Kobayashi, N. Shimada and T. Tanaka, Proceedings of ASME-JSME-KSME Joint Fluids Engineering Conference 211, AJK211-1211 (211). 5) A. Dhar and N. Shimada, 77 (CD-ROM), N16 (212). 6),, (23). 7) F. Xiao, Y. Honma and T. Kono., Int. J. Numer. Meth. Fluids, 48, 125 (25). 8) K. Yokoi, D. Vadillo, J. Hinch and I. Hutchings, Physics of Fluids, 21, 7212 (29). 2ms 1ms Fig. 14 Simulation of droplet deposition (Experiment by literature 8) 5) 212
PROFILE Naoki SHIMADA Tetsuya SUZUTA Tomonari KOBAYASHI 212