MODULES

Gas-Particle Flow Through A Vertical Channel

Problem Definition:

Simulations of gas-particle flow in a vertical channel (shown in Fig. 1.1) constituted by two parallel walls of length H and separated by a distance D are performed. The inlet velocity of both the phases is fixed at 2.0 m/s and the flow Reynolds number is set equal to 1378 which is lower than its transition value to turbulence for a single-phase flow between two parallel plates. The flow Reynolds number is adjusted by changing the viscosity of the carrier phase. The other physical conditions in the problem are as follows: H = 1.0 m,D = 0.1 m, ρg = 1.2 kg/m3, ρs = 1500 kg/m3.



Figure 1.1: Schematic diagram of the channel considered for the simulations


Results:

Numerical simulations for a set of particles having a value of particle Stokes number 0.61 has been carried out. The corresponding particle diameter based on this value of Stokes number is 252 μm. The simulations were performed for two different values of inlet particle phase volume fractions 0.0001 and 0.01. The changes in the flow physics of the gas phase has been studied as the particle phase volume fraction is changed from a very low value (0.0001) to a moderate value (0.01). Both drag and gravity have been considered in the simulations.
The gas phase velocity profiles for both the values of inlet particle phase volume fractions (0.0001 and 0.01) have been shown in Fig. 1.2(a); while the particle phase velocity profiles for these cases have been shown in Fig. 1.2(b). The results obtained by the solver have been compared with Passalacqua and Fox [1] and a reasonably good match has been found.


(a)



(b)

Figure 18.2: Plots of (a) gas phase velocity profile and (b) particle phase velocity profile at y = 0.5m of the channel

References

[1] Passalacqua A. and Fox R. (2011) ‘Advanced continuum modelling of gas-particle flows beyond the hydrodynamic limit’, Applied Mathematical Modelling, vol. 35, pp. 1616–1627.