Simplified Modeling of Deflagration in Vessels
Tóm tắt
A simplified method that models the deflagration process occurring in closed or vented vessels is described. When combustion occurs within the spherical or cylindrical vessels, the flame moves spherically or segmentally to the vessel periphery. The volume and area of each element along the propagating flame front are calculated by using simple geometrical rules. For instabilities and turbulence resulting in enhanced burning rates, a simple analysis results in reasonable agreement with the experimental pressure transients when two burning rates (a laminar burning rate prior to the onset of instability and an enhanced burning rate) were used. Pressure reduction caused by a vent opening at predetermined pressure was modeled. Parameters examined in the modeling include ignition location, mixture concentration, vented area, and vent opening pressure. It was found that venting was effective in reducing the peak pressure experienced in vessels. The model can be expected to estimate reasonable peak pressures and flame front distances by modeling the enhanced burning rates, that is, turbulent enhancement factor.
Tài liệu tham khảo
Bradley, D. and Mitchenson A., 1976, “Mathematical Solutions for Explosions in Spherical Vesels,”Combustion and Flame, Vol. 26, p. 210.
Bradley, D. and Mitchenson A., 1978a, “The Venting of Gaseous Explosions in Spherical Vessels I,”Combustion and Flame, Vol. 32, p. 221.
Bradley, D. and Mitchenson A., 1978b, “The Venting of Gaseous Explosions in Spherical Vessels II,”Combustion and Flame, Vol. 32, p. 237.
Canu, P., Rota, R. Carra, S., and Morbidelli, M., 1990, “Vented Gas Deflagrations ; A Detailed Mathematical Model Tuned on a Large Set of Experimental Data,”Combustion and Flame, Vol. 80, p. 49.
Canu, P., Rota, R., Carra, S. and Morbidelli, M., 1991, “Vented Gas Deflagration Modeling: A Simplified Approach,”Combustion and Flame, Vol. 85, p. 319.
Chatrathi, K., 1992, “Deflagration Protection of Pipes,”Plant/operation Progress, Vol. 11–2, p. 116.
Chippett, S., 1984, “Modeling of Vented Deflagrations,”Combustion and Flame, Vol. 55, p. 127.
Cousins, E. W. and Cotton, P. E., 1951, “Design Closed Vessels to Withstand Internal Explosions,”Chemical Engineering, Aug., p. 133
Epstein, M., Swift, I. and Fauske, H. K., 1986, “Estimation of Peak Pressure for Sonic-Vented Hydrocarbon Explosions in Spherical Vessels,”Combustion and Flame, Vol. 66, p. 1.
Fairwfather, M. and Vasey, M. W., 1982, “A Mathematical Model for the Prediction of Overpressures Generated in Totally Confined and Vented Explosions,”19 th Symposium International on Combustion, The Combustion Institute, p. 645.
Gardiner Jr., W. C., 1984,Combution Chemistry, Springer-Verlag, New York.
Garforth, A. M., 1976, “Unburnt Gas Density Measurement in a Spherical Combustion Bomb by Infinite-Fringe Laser Interferometry,”Combustion and Flame, Vol. 26, p. 343.
Garforth, A. M., and Rallis, C. J., 1978, “Laminar Burning Velocity of Stoichiometric Methane-Air: Pressure and Temperature Dependence,”Combustion and Flame, Vol. 31, p. 53.
Seo, S., 2003, “Combustion Instability Mechanism of a Lean Premixed Gas Turbine Combustor,”KSME International Journal, Vol. 17, p. 906
Takeno, T. and Iijima, T., 1979, “Theoretical Study of Nonsteady Flame Propagation in Closed Vessels,”AIAA, Aug., Vol. 119, p. 578.
Yun, K., Lee, S. and Sung, N., 2002, “A Study of the Propagation of Turbulent Premixed Flame Using the Flame Surface Density Model in a Constant Volume Combustion Chamber,”KSME International Journal, Vol. 16, p. 564