Browsing by Author "HUANG, LW"

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FLAME STABILIZATION AND BLOWOFF OVER A SINGLE DROPLET
(1995-01-01)
HUANG, LW
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CHEN, CH
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交大名義發表
;
機械工程學系
;
National Chiao Tung University
The burning behavior of a liquid fuel droplet under forced convection has been investigated numerically. The normalized governing system makes up the complete Navier-Stokes momentum, energy, species, and continuity equations in r-z coordinates with a one-step overall chemical reaction and finite-rate global kinetics. The evaporation process obeys the Clausius-Clapeyron law. The effects of incoming velocity (muBAR(infinity)) and droplet diameter (dBAR) are investigated separately. The envelope flame exists when free stream velocity is low. When uBAR(infinity) increases gradually, a critical velocity can be reached, at which the flame suddenly converts into a wake flame. No side falme is found. The envelope flames are retained throughout the decrement of the droplet diameter under the low-speed flow regime. The d2 law is found to still hold in such an environment.
SINGLE DROPLET COMBUSTION IN A GRAVITATIONAL ENVIRONMENT
(1994-07-01)
HUANG, LW
;
CHEN, CH
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
A theoretical analysis is developed to study the combustion characteristics of a fuel droplet in a gravitational field. The normalized governing system consists of the complete conservation equations in r-z coordinates and includes finite-rate global kinetics. The Clausius-Clapeyron law is applied at the liquid-vapor interface to describe the evaporation process. A modified body-fitted grid generation technique is used to handle irregular boundaries. The effects of changing the droplet diameter (dBAR) and the gravity level (gBAR) are investigated. Under the variation of droplet diameter, flame structures, including isotherms, flame shape, velocity vector field, and mass burning rate are studied in detail. The predicted results exhibit good agreement with experimental data. When the gravity level increases, the computed results show that the flame shape is sensitive to variation in gravity. A simple correlation, mBAR = m0BAR [1 + const. (alpha/gBAR)0.52], is found. Within the elevated gravity domain of experiment, the computed data agree well with measurements obtained by Okajima and Kumagai [10].