LES studies of the flow in a swirl gas combustor |
| |
Authors: | FF Grinstein C Fureby |
| |
Institution: | aNaval Research Laboratory, Laboratory for Computational Physics and Fluid Dynamics, Code 6410, Washington DC 20375-5344, USA;bThe Swedish Defence Research Agency, FOI, Department of Weapons and Protection, Warheads and Propulsion, SE-172 90, Stockholm, Sweden |
| |
Abstract: | Environmental and other practical concerns have led to the development of compact gas turbine combustors burning lean mixtures leading to potentially low CO and NOx emissions. The compact design requires efficient atomization and mixing together with a compact premixed flame. Associated with these requirements are higher temperatures, increased heat transfer, and thermal load, thus increasing the danger of combustion instabilities (causing performance deterioration and excessive mechanical loads), and possible off-design operation. Numerical simulations of reacting flows are well suited to address these issues. To this end, large eddy simulation (LES) is particularly promising. The philosophy behind LES is to explicitly simulate the large scales of the flow and the thermochemistry, affected by boundary conditions whilst modeling only the small scales, including the interaction between the flow and the combustion processes. Here, we examine the flow and the flame in a model gas turbine combustor (General Electric’s lean premixed dry low NOx LM6000) to evaluate the potential of LES for design studies of engineering applications and to study the effects of the combustor confinement geometry on the flow and on the flame dynamics. Two LES models, a Monotone Integrated LES model with 1 and 2 step Ahrrenius chemistry, and a fractal flame-wrinkling LES model coupled to a conventional one-equation eddy-viscosity subgrid model, are used. Reasonable agreement is found when comparing predictions with experimental data and with other LES computations of the same case. Furthermore, the combustor confinement geometry is found to strongly affect the vortical flow, and hence also the flame and its dynamics. |
| |
Keywords: | Large eddy simulation Premixed swirling flame Gas turbine combustor |
本文献已被 ScienceDirect 等数据库收录! |
|