Experimental Setting

This protocol is extracted from research article:

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

**
ACS Omega**,
Apr 5, 2021;
DOI:
10.1021/acsomega.1c00085

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

Procedure

The coaxial cylindrical chamber
in an experiment consists of the primary core zone and the secondary
annual jet zone. Diameters of the primary inject, annulus jet, and
main outer chamber are 32.0, 64.0, and 194.0 mm, respectively. The
total length test section that is oriented vertically with the gravity
acting in the direction of the flow is 960.0 mm. Predictions are laden
with the ultralight expanded graphite (EP) and the copper beads with
a density of 21.9 and 8900.0 kg/m^{3} with each diameter of
45.0 and 1000.0 μm, respectively. Glass beads are used to verify
the simulation result, which have 2500.0 kg/m^{3} density
and are 45 μm in diameter with Stokes number St = 0.025. As
for the gas phase, the initial primary central flow rate is 9.9 g/s,
the initial annular flow rate is 38.3 g/s, and the inlet Reynolds
number is 52,400. The particle mass flow rate is 0.34 g/s and the
particle loading in the primary flow η is 0.034, which is defined
as the ratio of the particle to gas phase mass flow rates in eq 1. The mass flow rates
correspond to the particle inertia leading to the different effects
on inlet flow structures. Larger inertia particles are easier to be
entrained to the primary central regions instead of secondary flow
regions.

The swirling number is set to 0.47 in this simulation (see eq 2). The date output positions are obtained at the length of 3.0, 52.0, 155.0, 195.0, and 315.0 mm along the streamwise directions. Detailed schematic diagrams are shown in Figure Figure11.

where *s* is the abbreviation
of swirling number, *a* is the annular jet, *r* is the radius, *d*_{a} is the diameter
of the annular jet, *u*_{g} and *w*_{g} are the axial and tangential gas velocity, respectively,
and ρ_{g} is the density of gas phase. A dimensionless
parameter, Stokes number St, is defined by St = τ_{s}/τ_{f} as eqs 3 and 4, which is used to classify the
degree of the particle entrainment into the gas flow. τ_{s} is the particle relaxation time and τ_{f} is
the fluid time scale, respectively.

Schematic diagram of a coaxial swirling chamber.

The experimental parameters and simulation settings are given as Table 2. Moreover, the interim value of St = 1.11 in between 43.6 and 0.002 using copper particles with diameter of 160.0 μm is also simulated to investigate the trend of the effect of Stokes number in-between on turbulence modulations.

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