2009 Volume 51 Issue 156 Pages 114-120
Stricter emissions legislation combined with the need to reduce greenhouse gas emissions drives fundamental research to produce cleaner, more efficient systems. Chemical kinetic mechanisms together with CFD codes are used to design more efficient and clean systems and optimize the operating behaviour of practical combustion devices such as internal combustion engines, gas turbines and other combustion devices.
However, in order to validate and produce accurate detailed chemical kinetic mechanisms, a wide range of data is needed, which is normally generated under well-controlled physical conditions of temperature, pressure, fuel/air ratio and dilution. These data include (i) ignition delay times recorded in shock tubes and in rapid compression machines, (ii) speciation data from flow reactors, jet-stirred reactors and flame experiments and (iii) flame measurements of laminar burning velocity. Typically, these mechanisms for hydrocarbon and oxygenated hydrocarbon systems are generated in a hierarchical way, starting first with the hydrogen/oxygen system, thereafter adding a carbon monoxide/carbon dioxide subset, followed by formaldehyde, methane and other larger C1-Cn species.
This work will discuss the development of detailed chemical kinetic mechanisms in the context of hierarchy and range of validation. Some typical problems associated with these mechanisms will be discussed and some ideas on how they may be addressed will be explored. Application of detailed kinetic mechanisms of water addition to gas turbines to increase efficiency and reduce emissions will be explored in some more detail.
