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Abstract
In. this paper, the development and validation of 3-dimensional computer code to analyze autoignition in a non-premixed medium under isotropic and homogeneous turbulence is presented. During autoignition the density changes are considerable and hence the constant density assumption cannot be made. To incLude the effects of density, fluctuations caused due to spatial inhomogeneities in temperature and species, a pressure based method is deveLoped herein, which is a spectral impLementation of the sequential steps followed in the predictor-corrector type of algorithms. The velocity and pressure field are solved in spectral space while the scalars are solved in physical space. The combustion is assumed to take pLace through a single-step irreversible reaction. Simulations are first validated for nonreacting turbulence without any scalars. Next, the decay, of scalar variance has been studied which showed a power law decay as observed by the earLier researchers. Then. the program is extended to analyze the reacting flow problems. The code has been parallelized using MPI calls to run it efficiently on IBM-SP machines. The details of the governing equations, solution methodology and comparison of present results with previous data are presented.
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References
- I. Heywood, J.B., "Internal Combustion Engine Fundamentals", McGraw-Hill, New York, I988, Chapter 10.
- Leonard, A.D. and Hill, J.C., "Scalar Dissipation and Mixing in Turbulent Reactive.Flows', Phys. Fluids, A 3(5). 1296-1299, 1991.
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- Lakshmisha, K.N., Zhang, Y., Rogg, B. and Bray, K.N.C., "Modeling Autoignition in a Turbulent Medium", Proc. Combust. Inst. 24,421,1992.
- Sreedhara, S. and Lakshmisha, K.N., "Direct Numerical Simulation of Autoignition in a Nonpremixed, Turbulent Medium", Proc. Combust. Inst., 28.25.2000.
- Kirn, J. and Moin, P., "Application of a Fractional- Step Method to Incompressible Navier-Stokes Equations", J. Comput. Phys., 59, 308, 1985.
- Canuto, C., Hussaini, M.Y., Quarteroni, A. and,Zang, T.A., Spectral Methods in Fluid Dynamics, Springer:, New YoLk, 1987.
- Issa, R.I.. "Solution of the implicity Discretised Fluid Flow Equations by Operator Spliting", J. Comput. Phys.,62,40, 1986.
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- Velvisch, L. and Poinsot, T., "Direct Numerical Simulation of Nonpremixed Turbulent Combustion", Ann. Rev. Fluid Mech. 30, 665, 1998.
- Mastorakos, E,., Baritaud, T.A. and Poinsot, T.J., "Numerical Simulations of Autoignition in Turbulent. Mixing Flows", Combust. Flame, 109, 198, 1991.
- Im, H.G., Chen, J.H. and Law, C.K., "Ignition of Hydrogen-air Mixing Layer in Turbulent Flows", Proc. Combust, Inst. 21, 1041. 1998.
- Wong, C.L. and Steele, D.E., "The Effects of Diesel Fuel Properties and Engine Operating Conditions on Ignition Delay", SAE Paper 82l23l,3873, I983.
- Baritaud, T.A., Heinze, T.A. and Le C oz, J .F., "Spray and Self-ignition Visualization in a DI Diesel Engine", SAE Paper 940681, 1129,1994.
- Erlebacher, G., Hussaini, M.Y., Speziale, C.C. and Zang,T.A., "Toward the Large-eddy Simulation of Compressible Turbulent Flows", J. Fluid Mech., 238, 155, 1992.
- McComb, W.D., The Physics of Fluid Turbulence, Clarendon Press, Oxford , 1991.
- Hasegawa, T.. Arai, A., Kadowaki, S. and yamaguchi, S., "Autoignition of a Turbulent Premixed gas". Combust. Sci. Technology. 84. l. 1992.
- Eswaran, V. and Pope, S.B., I'Direct Numerical Simulations of Turbulent Mixing of a Passive Scalar", Phys. Fluids A, 3I , 3, 506, 1988.
- McComb, W.D. and Shanmugasundaram, V., "Numerical Calculation of Decaying Isotropic Turbulence, using the LET Theory", J. Fluid Mech., 143, 95, 1984.
- Orszag, S.A. and Patterson, G;S., "Numerical Simulation of Three-dimensional Homogeneous Isotropic Turbulence", Phy. Rev. Lett.,28,16, 19'72.
- Mell, W.8., Kosaly, C. and Riley, J.J., "The Length Scale Dependence bf ScalarMixing", Phys. Fluids A, 3, t0,2414, 1991.
- Sreedhara, S. and Lakshmisha, K.N., (2002a), "Autoignition in a Non-premixed Medium : DNS Studies on the Effects of 3-Dimensional Turbulence", Proceedings of the Combustion Institute, 29, 2051.
- Sreedhara, S. and Lakshmisha, K,N., (2002b), "Assessment of Conditional Moment Closure Models of Turbulent Autoignition using DNS Data", proceedings of the Combustion Institute, 29,2069.
References
I. Heywood, J.B., "Internal Combustion Engine Fundamentals", McGraw-Hill, New York, I988, Chapter 10.
Leonard, A.D. and Hill, J.C., "Scalar Dissipation and Mixing in Turbulent Reactive.Flows', Phys. Fluids, A 3(5). 1296-1299, 1991.
Swarninathan, N. and Bilger, R.W., "Direct Numerical Simulation of Turbulent Non-premixed Hydro-carbon Flames Using a Two-step Reduced Mechanism", Combust. Sci. Tech. 121 , 161-196, 1991.
Mizutani, Y., Nakabe, K. and Chung, J.D., "Effects of Turbulent Mixing on Spray Ignition", Proc. Combust. Inst. 23. 1455. 1990.
Lakshmisha, K.N., Zhang, Y., Rogg, B. and Bray, K.N.C., "Modeling Autoignition in a Turbulent Medium", Proc. Combust. Inst. 24,421,1992.
Sreedhara, S. and Lakshmisha, K.N., "Direct Numerical Simulation of Autoignition in a Nonpremixed, Turbulent Medium", Proc. Combust. Inst., 28.25.2000.
Kirn, J. and Moin, P., "Application of a Fractional- Step Method to Incompressible Navier-Stokes Equations", J. Comput. Phys., 59, 308, 1985.
Canuto, C., Hussaini, M.Y., Quarteroni, A. and,Zang, T.A., Spectral Methods in Fluid Dynamics, Springer:, New YoLk, 1987.
Issa, R.I.. "Solution of the implicity Discretised Fluid Flow Equations by Operator Spliting", J. Comput. Phys.,62,40, 1986.
Jones, W.P,, "Turbulent Reacting Flows" (Eds : P.A. Libby and F.A. Williams), Chapter 6, Academic Press. 1994.
Velvisch, L. and Poinsot, T., "Direct Numerical Simulation of Nonpremixed Turbulent Combustion", Ann. Rev. Fluid Mech. 30, 665, 1998.
Mastorakos, E,., Baritaud, T.A. and Poinsot, T.J., "Numerical Simulations of Autoignition in Turbulent. Mixing Flows", Combust. Flame, 109, 198, 1991.
Im, H.G., Chen, J.H. and Law, C.K., "Ignition of Hydrogen-air Mixing Layer in Turbulent Flows", Proc. Combust, Inst. 21, 1041. 1998.
Wong, C.L. and Steele, D.E., "The Effects of Diesel Fuel Properties and Engine Operating Conditions on Ignition Delay", SAE Paper 82l23l,3873, I983.
Baritaud, T.A., Heinze, T.A. and Le C oz, J .F., "Spray and Self-ignition Visualization in a DI Diesel Engine", SAE Paper 940681, 1129,1994.
Erlebacher, G., Hussaini, M.Y., Speziale, C.C. and Zang,T.A., "Toward the Large-eddy Simulation of Compressible Turbulent Flows", J. Fluid Mech., 238, 155, 1992.
McComb, W.D., The Physics of Fluid Turbulence, Clarendon Press, Oxford , 1991.
Hasegawa, T.. Arai, A., Kadowaki, S. and yamaguchi, S., "Autoignition of a Turbulent Premixed gas". Combust. Sci. Technology. 84. l. 1992.
Eswaran, V. and Pope, S.B., I'Direct Numerical Simulations of Turbulent Mixing of a Passive Scalar", Phys. Fluids A, 3I , 3, 506, 1988.
McComb, W.D. and Shanmugasundaram, V., "Numerical Calculation of Decaying Isotropic Turbulence, using the LET Theory", J. Fluid Mech., 143, 95, 1984.
Orszag, S.A. and Patterson, G;S., "Numerical Simulation of Three-dimensional Homogeneous Isotropic Turbulence", Phy. Rev. Lett.,28,16, 19'72.
Mell, W.8., Kosaly, C. and Riley, J.J., "The Length Scale Dependence bf ScalarMixing", Phys. Fluids A, 3, t0,2414, 1991.
Sreedhara, S. and Lakshmisha, K.N., (2002a), "Autoignition in a Non-premixed Medium : DNS Studies on the Effects of 3-Dimensional Turbulence", Proceedings of the Combustion Institute, 29, 2051.
Sreedhara, S. and Lakshmisha, K,N., (2002b), "Assessment of Conditional Moment Closure Models of Turbulent Autoignition using DNS Data", proceedings of the Combustion Institute, 29,2069.