An investigation of the gas-fired pulsating combustor

Miscellaneous · Fri Jan 01 00:00:00 EST 1988

OSTI ID:7070545

Ku, S H

The work reported here was mainly experimental although a methodology was developed for determining the combustion efficiency from the analysis of the exhaust gases, and also, simple, linear and non-linear models were developed to predict the pulsation frequency and the level of the boost pressure in the pulse combustor. The performance measurements indicated that the pulse frequency and the performance of the gas fired, valved pulse combustor depends upon the volume of the combustion chamber and the size of the tailpipe. Combustion efficiencies are extremely high and CO and NO{sub x} emissions are very low for fuel lean conditions. Visualization showed the fuel jet entering the mixing chamber followed by a wide air jet. Highly turbulent combustion then takes place in small pockets moving in two counter rotating vortices. The early heat release under very fuel lean conditions results in much of the combustion energy being released out of phase with pressure pulsations causing damping and, therefore, leading to the existence of a fuel lean limit. On the other hand, the delay in heat release near stoichiometric conditions caused by the belated entry of the air jet seems to prevent sufficient heat to be released during the remainder of the cycle, in phase with the pressure oscillations to provide enough driving to overcome the inherent losses in the pulse combustor. A fuel rich limit of operation of the pulse combustor is, therefore, reached as the equivalence ratio approaches one. LDV measurements confirmed the existence of an axial vortex and the pair of counter rotating vortices during the combustion part of the cycle. Very high turbulence intensity levels were observed throughout the combustor at all instances during the cycle.

• Research Organization: Georgia Inst. of Tech., Atlanta, GA (USA)
• OSTI ID: 7070545
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PULSE COMBUSTORS
PERFORMANCE
CARBON MONOXIDE
COMBUSTION CHAMBERS
COMBUSTION CONTROL
DAMPING
DOPPLER EFFECT
EFFICIENCY
EMISSION
EXHAUST GASES
FLOW RATE
FLOW VISUALIZATION
FUEL-AIR RATIO
GAS FUELS
JETS
LASERS
MATHEMATICAL MODELS
NITROGEN OXIDES
OSCILLATIONS
PRESSURE CONTROL
PULSATIONS
TURBULENCE
VELOCIMETERS
VORTEX FLOW
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
COMBUSTORS
CONTROL
FLUID FLOW
FLUIDS
FUELS
GASEOUS WASTES
GASES
MEASURING INSTRUMENTS
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
WASTES
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry