It will cause more back pressure for the design theory of active silencer when widening noise control frequency or enhancing noise reduction, The acoustic characteristics of a conic diffuse are analyzed in the method of mathematics and acoustic-electric Analogy A low frequency silencer with low flow-resistance is proved.

Fully developed incompressible turbulent flow in a conical diffuser having a total divergence of 8° and an area ratio of 4 has been simulated by a DLR k-ε turbulence model and its BFC(Boundary Fit Coordinates) method.

Fully developed incompressible turbulent flow in a conical diffuser having a total divergence of 8° and an area ratio of 4 has been simulated by a DHR κ-ε turbulence model and it s wall function BFC(Boundary Fit Coordinates)approach.

Fully developed incompressible turbulent flow in a conical diffuser having a total divergence of 80 and an area ratio of 4 has been simulated by DHR k-ε turbulence model and its Wall Function·BFC(Boundary Fit Coordinates)approach.

The gasphase polycyclic aromatic hydrocarbons(PAHs)were trapped using annular denuder coated with XAD-2 resin that was applied from a hexane slurry.

Compared to annular denuder, the collection efficiency and capacity of honeycomb denuder were higher than annular.

An annular denuder system(ADS), which consisted of denuder tubes striping the reactive gases from air and leaving the particles on the filters was designed.