Unsteady spray-group combustion

Thesis/Dissertation · Sat Dec 31 23:00:00 EST 1988

OSTI ID:6376980

Lottes, S A

An unsteady spray combustion formulation is developed for the study of group combustion in axisymmetric spray combustion systems. The focus of the study ia on the interrelation between vaporization, combustion, and transport processes in a spray combustion system and: how these processes affect the transient development and collapse of group combustion structures. The unsteady formulation is targeted to modeling of unsteadiness at convective time scales. The numerical approach chosen is fully implicit in time. The two-space dimension steady state spray combustion computer code developed by Zhou and Chiu (1983) is extended to perform computations with the unsteady model formulation. Microcomputer software is developed to process the large amounts of data generated in an unsteady spray combustion computation into gray scale encoded picture graphic representations of variable values over the combustion field. These gray scale graphic results are employed in the analysis of processes in unsteady spray group combustion mode transitions. The unsteady spray combustion computer code and supporting microcomputer software is used in a case study to assess group combustion mode transitions and cycles brought on by changing inlet droplet number density in a simple cylindrical combustor. These studies identify the stages and mechanisms of formation and dissolution of global group combustion modes and assess the effects on the process and progress of the transitions when mean droplet size, spray angle, or droplet inlet temperature are changed. A brief look at the transient group combustion modes which develop periodically during the cycling of the spray injection process is also presented.

• Research Organization: Illinois Univ., Chicago, IL (USA)
• OSTI ID: 6376980
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMBUSTION
COMBUSTION KINETICS
COMBUSTORS
COMPUTER CODES
COMPUTER GRAPHICS
CONFIGURATION
CYLINDRICAL CONFIGURATION
DROPLETS
EVAPORATION
FLUID FLOW
FUEL INJECTION SYSTEMS
FUEL SYSTEMS
KINETICS
MASS TRANSFER
MATHEMATICAL MODELS
OXIDATION
PARTICLES
PHASE TRANSFORMATIONS
REACTION KINETICS
SPRAYS
THERMOCHEMICAL PROCESSES
TIME DEPENDENCE
TRANSIENTS
TWO-DIMENSIONAL CALCULATIONS
UNSTEADY FLOW