Electronic Journal of Differential Equations, Vol. 2004(2004), No. 40, pp. 1-22. Title: Homogenization in chemical reactive flows Authors: Carlos Conca (Univ. de Chile, Santiago, Chile) Jesus Ildefonso Diaz (Univ. Complutense, Madrid, Spain) Amable Linan (Univ. Politecnica de Madrid, Spain) Claudia Timofte (Univ. of Bucharest, Romania) Abstract: This paper concerns the homogenization of two nonlinear models for chemical reactive flows through the exterior of a domain containing periodically distributed reactive solid grains (or reactive obstacles). In the first model, the chemical reactions take place on the walls of the grains, while in the second one the fluid penetrates the grains and the reactions take place therein. The effective behavior of these reactive flows is described by a new elliptic boundary-value problem containing an extra zero-order term which captures the effect of the chemical reactions. Submitted April 3, 2003. Published March 22, 2004. Math Subject Classifications: 47A15, 46A32, 47D20. Key Words: Homogenization; reactive flows; variational inequality; monotone graph.