Estimates of turbulence mechanisms in circulating fluidized bed combustors

• Estimates of the characteristic time scales (particle relaxation time, eddy-particle interaction time, interparticle collision time), and the energy dissipation mechanisms are performed together with a turbulent kinetic energy budget, for a simple equilibrium shear flow with conditions similar to those of a circulating fluidized bed (CFB) combustor. Based on dimensional analysis, the influence of five parameters is investigated: the Eulerian integral length scale in the gas phase, the gas-particle density ratio, the mean velocity gradient, the particle diameter, and the particle volume fraction. The results show significant differences between particles of Geldart groups A and B regarding response to gas phase turbulence, transition from dense to dilute suspensions, pressure and temperature dependence, and also energy dissipation mechanisms.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering (hsv//eng)

Nyckelord

Fluidized beds

Gas-solid flow

Circulating beds

Combustors

Turbulence

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art (ämneskategori)

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