Flame acceleration studies in the MINIFLAME facility
Flame acceleration and deflagration-to-detonation transition (DDT) studies have been conducted in a 19.4-cm high, 14.5-cm wide, and 2. 242-m long channel (MINIFLAME) that is a 1:12.6 scale model of the 136-m{sup 3} FLAME facility. Tests were conducted with two levels of hydrogen concentration -- 20% and 30%, with and without obstacles in the channel, and with three levels of transverse top venting -- 0%, 13%, and 50%. The flame acceleration results in MINIFLAME are qualitatively similar to those in FLAME; however, the small-scale results are more benign quantitatively. The results show that insufficient venting, 13% venting in this case, can promote flame acceleration due to turbulence produced by the flow through the vents in smooth channels. However, with obstacle-generated turbulence in the channel, 13% top venting was found to be beneficial. Flame acceleration resulting in DDT was shown to occur in as little as 35 liters of mixture. Comparison of the DDT data with obstacles in MINIFLAME and FLAME supports d/{lambda} scaling of DDT, where {lambda} is the detonation cell width of the mixture and d is the characteristic open diameter of the channel. In the MINIFLAME and FLAME tests, DDT occurred for d/{lambda} greater than approximately three. Comparison with other experiments shows that the value of d/{lambda} for DDT is not constant but depends on the obstacle type, spacing, and channel geometry. The comparison of MINIFLAME and FLAME experiments extends the use of d/{lambda} scaling to different geometries and larger scales than previous studies. Small-scale-model testing of flame acceleration and DDT with the same combustible mixture as the full-scale prototype underpredicts flame speeds, overpressures, and the possibility of DDT. 18 refs., 16 figs.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- Sponsoring Organization:
- DOE/DP
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5618387
- Report Number(s):
- SAND-89-0859; ON: DE90000041
- Country of Publication:
- United States
- Language:
- English
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ACCELERATION
CHEMICAL PLANTS
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
COMBUSTION PROPERTIES
CONTAINMENT
DATA
DATA ACQUISITION
DATA ANALYSIS
DESIGN
DETONATIONS
DIMENSIONS
DISPERSIONS
ELEMENTS
EXPERIMENTAL DATA
FLAMES
GEOMETRY
HYDROGEN
IGNITION
IGNITION QUALITY
INDUSTRIAL PLANTS
INFORMATION
KINETICS
MATHEMATICS
MIXTURES
NONMETALS
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
NUMERICAL DATA
PETROCHEMICAL PLANTS
PHYSICAL PROPERTIES
POWER PLANTS
REACTION KINETICS
REACTOR SAFETY
SAFETY
SCALE MODELS
STRUCTURAL MODELS
TEST FACILITIES
THERMAL POWER PLANTS
THERMODYNAMIC PROPERTIES
VAPOR PRESSURE
VENTILATION
VENTILATION BARRIERS