A NUMERICAL-METHOD FOR SINGULAR PERTURBATION PROBLEMS ARISING IN CHEMICAL REACTOR THEORY

A class of singularly perturbed two point boundary value problems for second order ordinary differential equations with mixed boundary condi tions, arising in chemical reactor theory is considered. In order to s olve them, a numerical method is suggested, in which an exponentially fitted difference scheme is combined with classical numerical methods. The proposed method is distinguished by the following facts: first, w e divide the given-interval (the domain of definition of the different ial equation) into two subintervals called outer and inner regions. Th en, we solve the differential equation over both the regions as two po int boundary value problems. The terminal boundary condition of the in ner region is obtained using the zero order asymptotic expansion of th e solution. Some numerical examples are given to illustrate the method .