Dynamics of the flame flowfields in a low-swirl burner
The concept of using low swirl to stabilize lean premixed turbulent flame was introduced in 1992. Since then, the low-swirl burner (LSB) has become a useful laboratory tool for the study of detailed flame structures as well as turbulent burning speeds. Its main attribute is that the flame is freely propagating and is locally normal to the turbulent approach flow (Figure 1). Therefore, the turbulent flame brush is not influence by physical boundaries. The capability of LSB to support very lean flames and very turbulent flames [1, 2] was further exploited in recent studies to test the validity of the flame regime concept. Using 2D imaging diagnostics (e.g. planar laser induced fluorescence, PLIF, and planar laser induced Rayleigh scattering) our analysis showed that the wrinkled flame regime to be valid at a turbulence intensity level much higher than previously thought [3-5]. This provided experimental verification of a new 'thin reaction zone' regime for the Kalovitz number range of 1 < Ka < 10 (Ka = (u{prime}/s{sub L}){sup 3/2} (l{sub x}/d{sub L}){sup 1/2}) proposed by Peters. Due to its freely propagating nature, modeling and simulations of LSB flames are non-trivial. The flame position cannot be specified a priori because it is coupled to the turbulent flowfield and the turbulent flame speed may be required as input. This has not been a significant issue when treating the LSB flame as a close approximation to a 1D premixed turbulent flame. However, to support the development of more robust 3D simulation methods, accurate information on the flowfield dynamics in particular those at the burner exit and the interactions between the core and swirl air flows becomes important. In the past, velocity measurements in LSB have concentrated on collecting information along the centerline. The objective of this investigation is to conduct a detailed study using particle image velocimetry (PIV) to provide the flowfield information that are more suited to support 3D simulations.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Environmental Energy Technologies Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 925701
- Report Number(s):
- LBNL-53405; TRN: US200807%%616
- Resource Relation:
- Conference: 19th Colloquium on the Dynamics of Explosions and Reactive Systems, Hakone, Japan, July 26-Aug. 1, 2003
- Country of Publication:
- United States
- Language:
- English
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