99/03854 Performance enhancement in coal fired thermal power plants. Part I: boilers: Bhatt, M. S. and Jotribasu, S. Int. J. Energy Res., 1999, 23, (6), 465–487

Abstract

Results from multidimensional numerical simulations and cycle simulations are presented in an effort to optimize the performance of a fuel-lean-burn, homogeneous charge, natural gas spark-ignition internal combustion (IC) engine. The multidimensional numerical simulations are performed using modified versions of the KIVA-2 and KIVA-3 computer codes. The engine cycle simulations are performed using the WAVE code. The KIVA codes are enhanced with a turbulent combustion submodel which employs a two-step, natural gas/air chemical kinetics scheme with a temperature-dependent activation energy, together with a modified eddy dissipation model to treat the effects of turbulence on the burning rate. The output from the multidimensional calculations is used, in a novel way, as input to the WAVE cycle simulation code to predict overall engine performance. The Caterpillar G3400 and G3500 fuel-lean-burn natural gas engines are the specific engines under study. The predictions for brake specific fuel consumption (BSFC) are within 1% of the measured values for all cases where engine data are available. The effects of swirl, combustion chamber geometry, and spark location on burning rate and BSFC are investigated. Specifically, the results show that: (1) the numerical predictions are in good qualitative and quantitative agreement with engine data; (2) there is an optimum initial swirl ratio for the central bowl, central spark plug geometry; (3) an offset bowl results in a lower BSFC than a central bowl for the same initial swirl ratio and spark plug location; and (4) an offset spark plug results in a lower BSFC than a central plug for the same initial swirl ratio.