Slow Gas Flow Passing a Solid Is a Convection/diffusion Equation

Abstract

This paper exposes a formal result showing that a set of two coupled hyperbolic equations governing the thermal exchanges between a gas passing by a solid is actually close, in a detailed mathematical sense, to a single convection/diffusion equation. Exhaust gas passing by a solid catalyst is a typical example of such a situation. This result, the key derivation steps of which are given here, bridges the gap between the two formulations, which have received distinct types of contributions by the control community in the recent years.