DIRECT NUMERICAL-SIMULATION OF NON-PREMIXED TURBULENT FLAMES

Non-premixed turbulent combustion processes control most practical app lications of combustion. Studying these mechanisms has been the object ive of numerous theoretical and experimental works in the last century . In the past 10 years, direct numerical simulation (DNS) has emerged as a new methodology. It has become an essential tool to understand an d model turbulent combustion. DNS numerically solves the set of equati ons describing turbulent flames by resolving all chemical and flow sca les. Because formulated assumptions can be tested accurately, the resu lting data provide unique information to build turbulent combustion mo dels. This review first discusses the fundamental properties of lamina r diffusion flames. It then presents various DNS results to illustrate the different problems that can be studied using this tool. These pro blems include validity of the modeling hypothesis, topology of flame s urfaces, and ignition and extinction mechanisms. The review also discu sses the different analysis techniques employed to extract information from DNS and explores the limits of these methods.