A theoretical investigation of the effects of temperature, pressure, and equivalence ratio on the oxidation and reformed products of PRF90 under the flexible cylinder engine mode

In this study, the concept of flexible cylinder engine (FCE) by which a fuel is reformed in a flexible cylinder and rerouted into the normal cylinders was verified with the fuel of PRF90. The FCE mode consists of three processes: reforming, cooling, and working. The effect of operation conditions of flexible cylinder on the reforming process was investigated theoretically with CHEMKIN package. It shows that a large low-temperature reaction region in the flexible cylinder is formed with a change of initial operation conditions. An optimal fuel reforming region was found which is applicable at equivalence ratio of 1.0-2.0. In order to quantitatively assess the reactivity of reformed products, a reactivity coefficient index was defined. It is observed that addition of reformed products could reduce the ignition delay time of the fresh fuel. The reformed products of PRF90 from the flexible cylinder under the initial operation conditions of P = 1 bar, ϕ = 1.8, T = 353 K and P = 1 bar, ϕ = 1.0, T = 303 K have the strongest and weakest effect on reducing the ignition delay time of the fresh fuel, respectively. The current study could be helpful valuable to achieve controllable high efficiency and clean combustion.