Study on laminar combustion characteristics and the optimization of the coupling mechanism in a mixture of propanol and gasoline

Abstract

When both isopropanol and n-propanol are incorporated, the utilization of propanol as a fuel substitute (or a gasoline additive) presents promising potential for enhancing the combustion efficiency and thermal performance in compact, turbocharged, direct-injection gasoline engines upon blending. However, the complexity of the laminar combustion behavior of propanol-blended gasoline has yet to be fully investigated, as current coupling mechanisms are insufficiently sophisticated to precisely mirror the complex experimental conditions.

This study establishes a testbed specifically designed for measuring laminar burning velocity (LBV) using the heat flux method. This setup is employed to measure the LBV of pure n-heptane and isooctane, as well as the LBV of the gasoline surrogate fuel TRF with two distinct blend ratios. Additionally, it measures the LBV of propanol and its blends with TRF. The research findings reveal that isooctane demonstrates a heightened sensitivity to fuel preheating temperature, whereas the toluene proportion in TRF fuels exerts the most pronounced influence on combustion behavior. At an equivalence ratio of 1.1, the LBV of n-propanol differs from that of its isomer, isopropanol, by 4.65 cm/s. Notably, the LBV exhibits a discernible upward trend, corresponding to the increasing proportion of toluene in the blended fuel. Furthermore, there is a pronounced distinction in LBV among the propanol isomers, with blended TRF occupying an intermediate position between pure propanol and TRF. After the enhancement of the mechanism based on experimental benchmarks of LBV, a rigorous validation process demonstrated a substantial improvement in the alignment between simulated outcomes and empirical LBV measurements.