A computationally efficient combustion progress variable (CPV) approach for engine applications

Adina Werner, Corinna Netzer, Harry Lehtiniemi, Anders Borg, Andrea Matrisciano, Lars Seidel, Fabian Mauss

Abstract

The use of complex reaction schemes is accompanied by high computational cost in
3D CFD simulations but is especially important to predict emissions. A possible
solution to this dilemma is the use of tabulated chemistry. The approach presented
herein combines pretabulted chemistry look-up tables and the calculation of the
combustion progress based on chemical enthalpy. This work includes the
comparison between the combustion progress variable (CPV) model and an on-line
chemistry solver applying a reduced n-heptane mechanism and the emission
prediction for different EGR amounts applying the CPV model and a n-decane/α-
methyl-naphthalene mechanism. The simulations show in general a good agreement
between on-line and CPV model. Also, the soot and NOx emissions are reasonable.
The gain in CPU time depends on the mechanism size but is at least of factor 2 for
mechanisms of about 50 species.