The Progressive Spin Inlet - Homogeneous Flow Distributions Under Stringent Conditions

A new concept for achievement of homogeneous flow distributions in catalytic converters and particulate traps is presented. New applications such as NOx-adsorbers, SCR-catalysts and diesel particulate filters call for more homogeneous flow distributions. The new concept of the progressive spin inlet serves for homogeneous flow distribution within a short inlet cone. A spin is imposed on the flow at the outer radius of the catalyst inlet using helical-type flow elements. It is essential that the centre part of the flow is almost free of spin.

Best results can be obtained when the spin elements are designed to impose a progressive spin. The combination of a progressive slope angle and a progressive height serves for a relative minimum in pressure drop.

It is shown, that the progressive spin element also proves very good results with eccentric arrangements of the catalyst inlet cone. The parameters are optimised using CFD-calculations. The results agree well with velocity profile measurements and with flow visualisation in the catalyst inlet.