The laminar and turbulent characteristic time-scale combustion model is extended for general reactive flows. In this model, energy and species compositions relax toward their corresponding local chemical equilibrium state over a characteristic time. Chemical equilibrium is efficiently evaluated using in situ adaptive tabulation (ISAT). The model is applied to a steady-state simulation of Sandia Flame D. The model is useful for simulations where kinetic mechanisms are not available, and also to provide good initial conditions for calculations with full chemical kinetics. (C) 2011 The Combustion Institute. Published by Elsevier Inc. All rights reserved.