ENGINEERING AND CFD

A series of highly resolved direct numerical simulations (DNSs) of temporally evolving turbulent non-premixed jet flames was conducted on the SuperMUC of LRZ. Two promising approaches were used to analyze the databases. The first approach, on-the-fly tracking flamelet structure, helps to understand the effects of neglecting tangential diffusion (TD) on the performance of classical flamelet models. The second approach - dissipation elements – helps to develop possible closure strategies for including flame-tangential effects in the flamelet models. Moreover, TD was used as an important performance indicator to assess tabulation strategies, differential diffusion effects, and Soret effects in turbulent non-premixed combustion.

Spray evaporation and burning in a turbulent environment is a configuration found in many practical applications, such as diesel engines, direct-injection gasoline engines, gas turbines, etc. Understanding the physical process involved in this combustion process will help improving the combustion efficiency of these devices and, therefore, reduce their emissions. Direct numerical simulation (DNS) is a very attractive tool to investigate in all details the underlying processes since it is able to capture and resolve all scales in the system. In this project, evaporation, ignition, and mixing are investigated in both temporally- and spatially-evolving jets, using DNS.