Towards Next Generation Control-Oriented Thermo-Kinetic Model for Reactivity Controlled Compression Ignition Marine Engines

With low-temperature combustion engine research reaching an applicable level, physics-based control-oriented models regain attention. For reactivity controlled combustion concepts, chemical kinetics-based multizone models have been proven to reproduce the governing physics for performance-oriented simulations. They offer accuracy levels similar to high-fidelity computational fluid dynamics (CFD) models but with a fraction of their computational effort. Nevertheless, state-of-the-art reactivity controlled compression ignition (RCCI) simulations with multizone model toolchains still face challenges related to predictivity and calculation speed. This study introduces a new multizone modelling framework that addresses these challenges. It includes a C++ code, deeply integrated with open-source, thermo-kinetic libraries, and coupled to an industry standard 1-D modelling framework. Incorporating a predictive turbulence mixing model, it aims to eliminate dependence on CFD-based initialisation, while applying a novel zonal configuration to achieve sensitivity to the combustion chamber?s geometrical features. Basic sensitivity simulations performed for zonal resolution and chemical kinetic mechanisms prove the approach is fit for purpose. Aiming for optimal trade-off between accuracy and simulation speed, the 12-zone model has a simulation time below three minutes per closed cycle. These achievements are validated against a medium-speed, large-bore, single-cylinder research engine, running in a dual-fuel mode with natural gas and light fuel oil. Using basic submodels, the framework reproduces measured in-cylinder pressure trace within an RMS error of 0.85 bar, and combustion performance indicators within a 5% error margin target. Ultimately, this is the first time the multi-zone kinetic framework has been proven suitable to reproduce RCCI combustion on a state-of-the-art marine engine geometry.