| A numerical and experimental study of turbulent flow through and around expanded metal screens partially covering the cross-section of a low turbulence wind tunnel was accomplished. Expanded metal screens are used within pulverized coal-fired utility boilers to counteract the erosive action of fly-ash particles by reducing excessive particle-laden flue-gas velocities and by redistributing the fly-ash particle concentration.;Three screen types at three screen heights were studied. Higher cross-sectional coverage resulted in higher pressure drops, flow deflection, and velocities downstream of the screens. Higher screen solidity ratios resulted in higher pressure drops, velocity reduction by screens, velocity acceleration above the screens, and turbulence generation. Plane turbulent mixing layers were produced by the shearing action of the screens' upper edge, resulting in increased turbulence generation and pressure loss.;FLUENT was used to numerically simulate the screens. Numerical models predicted the flow field downstream of the screens successfully. |
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