Prediction of flame blowoff limits for hydrogen-air mixtures over an isolated vee-gutter flameholder using a well-stirred reactor model

Author

Julie Ann Darnell

Date of Award

8-1995

Degree Type

Thesis

Degree Name

Master of Science

Major

Mechanical Engineering

Major Professor

Roy J. Schulz

Committee Members

Roger Crawford, F, Shahrokhi

Abstract

The purpose of this research was to begin initial development of an analytical tool to predict flame blowoff limits for hydrogen-air mixtures over vee-gutter flameholders. A specific geometric configuration of an isolated vee-gutter was selected to represent a flameholder test apparatus described in the literature. An analytical tool was developed by treating the recirculation zone behind the vee-gutter as a homogeneous chemical reactor, modeling the recirculation zone as a well-stirred reactor and using LSENS, a chemical kinetics code, to solve the governing equations of the reacting flow. The well-stirred reactor was assumed adiabatic and operated under steady-state conditions. The well-stirred reactor model was applied to premixed, turbulent hydrogen-air mixtures over the vee-gutter configuration. To calibrate the well-stirred reactor model, appropriate values of the recirculation zone volume from existing experimental data for hydrogen-air mixtures at given freestream static pressures were determined. The freestream, blowoff velocities were predicted for static pressures fi-om 1.5 psia to 6 psia and static temperatures from 530 °R to 930 °R.

The blowoff limits predicted by LSENS were compared to existing experimental data on axisymmetrical disks corrected for two-dimensional flameholders at a given pressure. A parametric study of the model predictions was conducted to analyze the effects of pressure, temperature, fuel-air equivalence ratio and Reynolds number on flame stability. Conclusions were drawn regarding the accuracy and potential use of the model. The well-stirred reactor model developed in this study provides a useful preliminary survey of flame blowoff limits for premixed, turbulent hydrogen-air mixtures over the specific geometric configuration.

Recommended Citation

Darnell, Julie Ann, "Prediction of flame blowoff limits for hydrogen-air mixtures over an isolated vee-gutter flameholder using a well-stirred reactor model. " Master's Thesis, University of Tennessee, 1995.
https://trace.tennessee.edu/utk_gradthes/11090