Patent ID: 7549350
Filing Date: 2009-06-23
Classification: G01N

Abstract:
1. A dilution tunnel, comprising: a porous tube having an inlet fluidly coupled to an exhaust gas producing source, an outlet, and a flow axis passing through said porous tube, the inlet, and the outlet, said porous tube defining an internal flow passage for exhaust gas between the inlet and the outlet, the flow axis defining an axial flow direction of the exhaust gas through said porous tube, and the internal flow passage being substantially symmetrical about the flow axis; said porous tube including a porous section having a plurality of open pores formed in a wall of the porous tube that communicate between an outside region external of said porous tube and the internal flow passage, said pores being adapted to introduce a diluting gas from the outside region into the internal flow passage; and wherein a porosity of said porous section varies in at least one of the axial flow direction and around a periphery of the porous tube.