Abstract ▼

IV. Results of Research and Development
[ 1^st year ]
1. Flame extinction behavior for the gas extinguishers of CO₂ in normal gravity
1) Acquiring C-curve
2) Find flame oscillation modes: growing, harmonic, and decaying modes
3) Acquiring the regimes of edge flame

IV. Results of Research and Development
[ 1^st year ]
1. Flame extinction behavior for the gas extinguishers of CO₂ in normal gravity
1) Acquiring C-curve
2) Find flame oscillation modes: growing, harmonic, and decaying modes
3) Acquiring the regimes of edge flame oscillation in flame stability maps

2. Flame extinction behavior for the gas extinguishers of N₂ in normal gravity
1) Acquiring C-curve
2) Finding flame extinction modes: extinction through the shrinkage of the outermost edge flame with having edge flame oscillation (regime I), that without having edge flame oscillation (regime II), and extinction via a flame hole at high strain rate
3) Confirming that low strain rate flame extinction is not caused by radiative heat loss but the radial conductive heat loss from flame surface temperature measurement and comparison of each fraction to chemical source term in energy equation

3. Flame extinction behavior for the gas extinguishers of He in normal gravity
1) Acquiring C-curve
2) Acquiring the regimes of edge flame oscillation in flame stability maps
3) Find flame oscillation modes: growing, harmonic, and decaying modes

[ 2^nd year ]
1. Developing the experimental technology to minimize buoyancy force
1) Developing the experimental technology to obtain the level of 0.01g using He-curtain flow
2) Confirmed that edge flame oscillation was suppressed by increasing buoyancy force via adding N₂ to He-curtain flow

2. Effect of edge flame oscillation on flame extinction in case of increasing buoyancy force via adding N2 to He-curtain flow
1) Comparison of N₂-curtain flow with He-curtain flow for the feect of edge flame oscillation on flame extinction
2) Comparison between the phase diagrams to grasp the buoyancy effect on edge flame oscillation due to the heat loss
3) Grasping problems in He-curtain upward flow
4) Inspecting buoyancy effects in the counterflow burner with both-directional He-curtain flow

[ 3^rd year ]
1. Grasping the characteristics of C-curve in terms of adding N2 and He to fuel in both-directional He-curtain flow
1) Acquiring C-curves in terms of global strain rate at various burner diameters (10, 20,and 25 mm)
2) Evaluated the level of microgravity for each flame condition

2. Effect of edge flame oscillation on flame extinction in case of addition of He and N₂ to fuel in both-directional He-curtain flow
1) measured flam length in terms of global strain rate
2) Confirming that low strain rate flame extinction is not caused by radiative heat loss but the radial conductive heat loss from flame surface temperature measurement and comparison of each fraction to chemical source term in energy equation
3) In microgravity, we found flame extinction modes: extinction through the shrinkage of the outermost edge flame with having edge flame oscillation (regime I), that without having edge flame oscillation (regime II), and extinction via a flame hole at high strain rate
4) Grouped different oscillation modes in terms of global strain rate and the mole fraction of He and N₂

3. Preliminary experiments on the effect of modifying local flame condition on flam extinction in He curtain both-directional flow
; We investigate the possibility whether flame extinction modes can be affected each other at the global strain rate via varying inner and outer diluent mole fractions.

[ 4^th year ]
1. Modification of triple coflow counterflow burner

2. Grasping flame extinction conditions in terms of inner and outer nozzle stream concentrations in triple coflow counterflow burner
1) Acquiring C-curve in terms of He mole fraction and strain rate
2) For several fixed strain rates, acquiring C-curve in inner and outer He mole fractions

3. Grasping flame extinction modes in terms of inner and outer nozzle stream concentrations in triple coflow counterflow burner
1) For fixed inner nozzle stream He mole fraction, examining flame extinction modes according to outer nozzle stream concentration and strain rate
2) For fixed outer nozzle stream He mole fraction, examining flame extinction modes according to inner nozzle stream concentration and strain rate