Characteristic length of fuel and oxygen consumption in feed channels of polymer electrolyte fuel cells

How much of feed channels is actually used in a fuel cell? This problem is considered in this paper where we study gas or liquid feed consumption in t he feed supplying channels of a polymer electrolyte fuel cell. Simple analy tical expressions which define profiles of feed concentration along the cha nnel and expressions for characteristic length of feed consumption are obta ined. For typical conditions this length could be as low as several tens of centimeters. The dependence of consumption length on reaction rate paramet ers and system parameters is discussed. Analytical results are in good agre ement with data of simulation, performed specially to verify the validity o f the theory. (C) 2001 Elsevier Science Ltd. All rights reserved.