A Study of Confined Diffusion Flames

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Abstract:

A numerical simulation of an axisymmetric confined diffusion flame formed between a H2 - N2 jet and coflowing air at 30 cms is presented in this paper. For the initial computations, the restrictions of the Burke Schumann theory are imposed and the results of the computation are compared with the analytical solution for flame location. For both the underventilated and overventilated flames, the results of the computations are in excellent agreement with the analytical solution. However, the flame behavior becomes more complex as the restrictions are relaxed. When variable diffusion coefficients and densities are included in the calculation, small radial velocities are induced and the flame interface is slightly distorted. When heat release is included, the flame is shorter and an unsteady mixing region forms at the fuel oxidizer interface. The instabilities are damped when viscous effects are included. Large scale instabilities form in the oxidizer region with a frequency of approximately 15-20 Hz when gravity is included in the calculation.

Author(s):
Ellzey, J. L. ; Laskey, K. J. ; Oran, E. S.
Author Organization(s):
NAVAL RESEARCH LAB WASHINGTON DC
Descriptive Note:
Memorandum rept.
Supplementary Note:
Prepared in cooperation with Berkeley Research Associates, Springfield, VA and Grumman Space Station Program Support Div., Reston, VA.
Pagination:
0033

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release
Distribution Statement:
Approved For Public Release; Distribution Is Unlimited.

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
NRL-MR-6704
Task Number(s):
ON280071
Project Number(s):
ON280
Monitor Series:
NRL
 Subject Terms
Joint Capability Areas:
JCA_5.3_Planning; JCA_5_Command and Control; JCA_3.2_Engagement; JCA_3_Force Application; JCA_3.2.1_Kinetic Means; JCA_JCA_4.1.2_Sustain the Force; JCA_4.1_Deployment and Distribution
Communities of Interest:
Energy and Power Technologies
Descriptor(s):
*TURBULENT DIFFUSION, *FLAMES, INTERFACES, VARIABLES, FUELS, SOLUTIONS(GENERAL), AXISYMMETRIC, RELEASE, OXIDIZERS, GRAVITY, CONFINEMENT(GENERAL), DIFFUSION COEFFICIENT, HEAT, VISCOSITY, DIGITAL SIMULATION, ANALYTIC FUNCTIONS, RADIAL VELOCITY, POSITION(LOCATION), COMPUTATIONS
Field(s)/Group(s):
Combustion and Ignition
Keyword(s):
PE61153N, WU44153000, BURKE SCHUMANN THEORY
Report Date:
1990 Sep 04