Abstract
This work investigates the effects of the wall on the morphologic characteristics of non-premixed buoyancy driven turbulent flames attached to the wall. Experiments are carried out with rectangular burners having their long side attached to a wall. The investigation is based on dimensional analysis and comprehensive experimental data, including comparison of the flame characteristics of the wall attached flames with free flames. Results show that the non-dimensional flame heights of wall attached flames experience a two-dimensional to three-dimensional transition as free flames do. The critical dimensionless heat release rate for this transition is smaller for the wall attached flames (0.30) than that of the free flames (0.39). The flame height fluctuation of wall attached flames is smaller than that of free flames and decreases with an increase in the nozzle aspect ratio. The ratio of flame thickness (or flame width) to flame height of wall attached flames is smaller than that of free flames. New correlations for flame height, width and thickness of the wall attached flames are proposed based on the mirror-approach of the rectangular source relative to that of a free flame, where the burner perimeter is found to be an appropriate length scale. This work provides important knowledge on the effect of wall on flame characteristics of buoyancy driven turbulent flames, which is essential to the design and risk assessment of the laying of gaseous fuel transportation pipelines in the city and also provides data for validation of computational fluid dynamics (CFD) models.
| Original language | English |
|---|---|
| Article number | 113672 |
| Pages (from-to) | 1-13 |
| Number of pages | 13 |
| Journal | Applied Energy |
| Volume | 254 |
| Early online date | 21 Aug 2019 |
| DOIs | |
| Publication status | Published (in print/issue) - 15 Nov 2019 |
Keywords
- Wall attached buoyancy driven turbulent flames
- Flame height
- Flame fluctuation
- Flame thickness
- Flame width
- Heat release rate
