PDF mixing time scales for premixed combustion in the laminar flame limit |
| |
| Institution: | 1. Institut für Technische Verbrennung, Universität Stuttgart, Pfaffenwaldring 31, Stuttgart 70569, Germany;2. Simulation reaktiver Thermo-Fluid Systeme, TU Darmstadt, Otto-Berndt-Straße 2, Darmstadt 64287, Germany;3. Reaktive Strömungen und Messtechnik, TU Darmstadt,Otto-Berndt-Straße 3, Darmstadt 64287, Germany;1. Lehrstuhl für Thermodynamik, Technische Universität München, Garching, Germany;2. Institute for Advanced Study, Technische Universität München, Garching, Germany;3. Institute of Energy Systems and Fluid-Engineering, Zürich Univerity of Applied Sciences, Winterthur, Switzerland;1. Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, 117576 Singapore;2. Key laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China;3. Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA;4. Center for Combustion Energy, Tsinghua University, Beijing 100084, China |
| |
| Abstract: | A new mixing time scale for PDF calculations of premixed combustion in the laminar flame limit is introduced. It is based on the characteristics of the “random walk” diffusion process and accurately captures scalar micro-mixing such that physical features of the premixed flames are preserved. The speed of a freely-propagating laminar flame can be captured accurately. Extreme stochastic events may, however, lead to flame acceleration, but flame stability can be recovered with the introduction of a conditioning variable that relaxes towards an Eulerian reference field. With conditioning the predicted flame speed is quite insensitive towards the exact value of the only modelling parameter. This modelling parameter then allows to control the minor scalar fluctuations and deviations from a flamelet structure which is thought to be one of the key features of conditioning methods. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
