The application of orthogonal collocation to laminar flow heat and mass transfer in monolith converters

A comprehensive theoretical study of the monolith converter is performed. This chemical reactor was used for the oxidation of carbon monoxide and hydrocarbons in automobile exhausts, and consists of an array of wall catalyzed cells or ducts through which the gas passes in laminar flow. A series of mathematical models for the device are proposed and solved. For the more complex models the problem is a full three dimensional transient one, and is complicated by the irregular geometry of the cells and a highly nonlinear reaction rate expression. A solution method was developed and applied, so that these complex model equations can be solved. The method utilizes the eigenvalues and other constants which result from the solution of laminar flow heat transfer problems. The orthogonal collocation method is reviewed and extended to problems with irregular boundaries. This method is used in the solution of the laminar flow heat transfer problems, and to model conduction and diffusion in the monolith wall.