Modeling of swirl in turbulent flow systems
Abstract
Available theoretical and experimental techniques for modeling swirling flows are surveyed, with emphasis on identifying conditions which encourage vortex breakdown. The effects of incremental adjustments to the swirl level, flow rate, velocity ratios or duct geometries are discussed. The capabilities and limitations of the k-epsilon model are evaluated, noting its deficiencies for predicting processes in a toroidal recirculation zone. An examination of coal combustion in swirling flows shows that homogeneous mixtures can be expected before and after the recovery region. However, downstream concentrations are controlled to a large extent by particle dispersion and devolatilization and heterogeneous oxidation reactions, and cannot be modeled simply in terms of a swirling flow.
- Publication:
-
Progress in Energy and Combustion Science
- Pub Date:
- 1986
- Bibcode:
- 1986PrECS..12..163S
- Keywords:
-
- Computational Fluid Dynamics;
- Recirculative Fluid Flow;
- Swirling;
- Turbulent Flow;
- Boundary Value Problems;
- Boussinesq Approximation;
- Eddy Viscosity;
- Isothermal Flow;
- K-Epsilon Turbulence Model;
- Richardson Number;
- Stress Concentration;
- Fluid Mechanics and Heat Transfer