COMBUSTION ENGINEERING PROF. SEUNG WOOK BAEK DIV. OF AEROSPACE ENGINEERING, KAIST, IN KOREA ROOM : 3304 TELEPHONE : 3714

BURNING OF A FUEL DROPLET IN AN OXIDIZED ATMOSPHERE PROBLEMS HOW TO PRODUCE SPRAYS CHARACTERISTICS OF THE SPRAY BURNING RATE OF SPRAY? OXIDIZER PRESSURE AMBIENT TEMPERATURE EFFECTS OF MICRO EXPLOSION METAL PARTICLE SLURRY IGNITION PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING DROPLET MAY INTERACT IF CLOSE TOGETHER GROUP COMBUSTION INDIVIDUAL DROPLET COMBUSTION EFFECT OF CONVECTION EFFECT OF BUOYANCY OXIDIZER FUEL BURNING OF AN INDIVIDUAL DROPLET FLAME SURFACE PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING TYPICAL EXPERIMENTS EXCESSIVELY LARGE SIZE PRECLUSION OF TRANSIENT PHENOMENA QUARTZ FILAMENT DISTORTION HEAT LOSS SUSPENSION TECHNIQUE SUSPENDED DROPLET FUEL POROUS SPHERE (A) (B) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING FREE FALLING DROPS ZERO g EXPERIMENTS FORCED CONVECTION (C) (D) BUOYANCY EFFECT (1) BURNING RATE IS INCREASED DUE TO ENHANCED TRANSPORT RATES (2) FLAME SHAPE IS SEVERELY DISTORTED: NOT MEANINGFUL TO IDENTIFY A FLAME DIAMETER PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING IN (A) FOR STEADY BURNING (1) : SPHERE RADIUS IN (B) AND (C) AFTER AN INITIAL UNSTEADY PERIOD (2) : DROPLET DIAMETER : EVAPORATION CONSTANT(BURNING CONSTANT) LAW: ALSO VALID FOR PURE VAPORIZATION ANALYSIS DERIVATION OF EQUATION (2): PREDICTS BURNING RATE: FLAME SHAPES: TEMPERATURE AND CONCENTRATION PROFILES PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING ASSUMPTION (1) SPHERICAL SYMMETRY (2) USE SINGLE STEP REACTION (3) Shvab-Zeldovitch FORMULATION (4) STEADY COMBUSTION (i) HEATING AND IGNITION PERIODS NEGLECTED (THE FLOW VARIABLES ARE CONSTANT INSIDE THE DROPLET) (ii) CHANGES AS DROPLET VAPORIZES: AT MOST USING QUASI STEADY THEORY PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING BECAUSE OF THE SIGNIFICANT DENSITY DISPARITY BETWEEN LIQUID AND GAS, THE PROPERTIES AT THE DROPLET SURFACE SUCH AS THE REGRESSION RATE, SPECIES CONCENTRATIONS, AND TEMPERATURE IN LIQUID PHASE CHANGE AT RATES MUCH SLOWER THAN THOSE FOR THE GAS PHASE TRANSPORT PROCESSES (3) (4) IF (5) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING THE BURNING RATE? (6) WILL BE AN EIGENVALUE OF (7) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING COMBINE (6) AND (7) (8) ( IS INDEPENDENT OF r ) LET (9) (10) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING IF (11) FROM (5) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING CONSIDER THERMAL COUPLING FCN B.C. PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING DROPLET SURFACE SPECIES CONSERVATION (GO TO APPENDIX) NO SURFACE REACTION INTERFACE IS NOT MOVING. NO EXCESS MASS AT SURFACE PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING (12) FOR OXIDIZER (NO DISSOLUTION INTO DROPLET) USE (13) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING INTERFACE CONDITION ON T FOR UNIFORM AND CONSTANT DROPLET TEMPERATURE (14) L = LATENT HEAT OF VAPORIZATION INTRODUCE PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING (15) BY MAKING TERM INVOLVING DROPS OUT COMBINE RESULTS (13) & (15), (16) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING APPLY FOR (17) (18) AS (19) (20) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING (20) FROM DEFINITION OF (21) USING DEFINITION OF FROM EQUATION (20), (22) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING DISCUSSION (EQUATION (22)) CAN BE VARIABLE DOES NOT DEPEND ON FLAME SURFACE APPROXIMATION ( : FLAME SURFACE APPROXIMATION) : BASIC FUEL PROPERTIES GENERALLY KNOWN : FOR BURNING DROPS : USUALLY KNOWN IF AMBIENT ATMOSPHERE IS SPECIFIED PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING Tl IS DETERMINED BY THERMODYNAMIC CONDITION, SUCH THAT AT THE SURFACE = THEREFORE, WE NEED TO KNOW FREQUENTLY USED ONE IS Clausius-Clapeyron RELATION. : NORMAL ATMOSPHERIC PRESSURE & BOILING TEMPERATURE : PREVAILING PRESSURE FUEL BOILING TEMPERATURE, (GOOD APPROXIMATION) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING (23) (24) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING (25) (ACCURATE KNOWLEDGE OF Tb IS NOT ESSENTIAL) (SIMILARITY BETWEEN VAPORIZATION & COMBUSTION) B PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING FROM EQUATION (5) (26) REMARKS INSENSITIVE TO PRESSURE, WEAKLY DEPENDENT ON TEMPERATURE PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING OTHER CHARACTERISTICS OF BURNING DROPLETS SOLVED FOR 2nd ORDER EQUATIONS 3 B.C’s FLAME LOCATION? (27) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING AS ASSUME AS (28) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING AT DROPLET SURFACE, (29) BECAUSE OF AT DROPLET SURFACE, PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING (20) (21) (28) (29) (30) COMBINE : (28), (29), (30) FOR UNKNOWNS SOLVE FOR (31) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING CONCENTRATION PROFILE AND TEMPERATURE FLAME SURFACE APPROXIMATION AT FLAME PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING PROFILES 1 PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING (32) (27) WHEN (33) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING ASSUME USE EXPRESSION FOR IF PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING REMARK INDEPENDENT OF (DROPLET RADIUS) TOO LARGE BY A FACTOR OF 2 BECAUSE NATURAL CONVECTION IS NEGLECTED PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING MODERN DEVELOPMENTS NOT SPHERICALLY SYMMETRIC, BUT MULTIDIMENSIONAL TRANSIENT EFFECTS IN SURFACE REGRESSION RATE AND INTERIOR DROPLET HEATING MULTICOMPOSITIONAL WITH VARYING VOLATILITIES DROPLET INTERACTIONS THERMODYNAMIC NON-IDEALITY: DISSOLUTION OF AMBIENT GA IN LIQUID DROPLET, REAL EQUATION OF STATE, REAL THERMODYNAMIC PROPERTIES PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING APPENDIX CONDITION AT FLAME SURFACE AND THE NATURE OF THE FLAME SURFACE APPROXIMATION OXIDIZER FUEL ai = INTERFACE AREA v = VOLUME OF CONTROL VOLUME FROM Leibnitz RULE WITH USING PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING MOTION OF THE C.V. USING DIVERGENCE RULE PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING WHEN THE INTERFACE (C.V.) DOES NOT MOVE CONSERVATION OF SPECIES BECOMES (*) FOR i = F, (**) PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING ALL FUEL FLOWING TOWARD THE FLAME FRONT + SIDE IS CONSUMED AT THE FLAME SURFACE FOR i = 0 (***) FOR SINGLE STEP CHEMICAL REACTION : RATE OF PRODUCTION PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING DIVIDE (**) BY (***) BY AND SUBTRACT WHEN FUEL + OXIDIZER FLOW INTO FLAME FROM OPPOSITE SIDES IN STOICHIOMETRIC PROPORTIONS, AT FLAME PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING CONCENTRATION GRADIENTS REMAIN FINITE AT THE FLAME DIFFUSION FLUX IN STOICHIOMETIC PROPORTIONS PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING

COMBUSTION ENGINEERING REMARKS TEMPERATURE? SOLVE FOR AND PRODUCT? SOLVE FOR AND BASIC PROPERTIES OF DIFFUSION FLAME ARE ESTABLISHED WITHOUT CONSIDERATION OF REACTION RATES I.E. CHEMICAL KINETICS PROPULSION AND COMBUSTION LABORATORY COMBUSTION ENGINEERING