| 摘要 |
PROBLEM TO BE SOLVED: To rapidly achieve the homogenization by diffusion of ammonia into an exhaust gas by supplying ammonia in such a state that the flow of the gas is more easily diffusable without regulating the flow of the exhaust gas uniformly. SOLUTION: A guide blade 52 made up of an inclined long-size plain plate is provided on each of the inner faces of four walls on a duct 51 for generating a swirl throughout the duct 51. The size of the blade 52 is decided depending upon the intensity of the swirl to be set. In addition, the length L of the blade 52 in the duct 51 is almost 1/2 to 1 time the width A or the height of the duct 51 and the swirl can be efficiently generated, when the width H of the blade 52 is 20% or more as much as the width A or the height of the duct 51. Further, the width H of the guide blade 52 can be extended as far as the center of the duct 51. The angle of attack θ of the guide blade 52 is set within a variable range in accordance with the intensity of the swirl. When it is desired that the maximum flow velocity W of the swirl be obtained for the flow velocity U of an exhaust gas in the main current direction, the equation θ=tan<-1> (W/U) is to be satisfied. |
