Abstract
Abstract
The knock prediction method by the multidimensional calculation, which combined Flamelet model and Shell model, was reported in previous study. It was possible to predict knock onset location qualitatively by this method. However, it has also been reported that minor inconsistencies have been detected in the prediction of a knock onset location and timing. As the factors of such discrepancies, those were thought that 1) Shell model parameters that were proposed by Halstead, have inconsistence, 2) the characteristics of ignition delay of PRF which was used as alternative fuel of gasoline, differs from gasoline´s one, and 3) The end gas temperature in the combustion chamber was not correctly predicted due to the use of the steady, incompressible wall function that has been proposed by Launder, et al. as the wall heat transfer model. To fix these issues, reaction rates constants were optimized by referring gasoline surrogate scheme that was proposed by Golovichev. In addition, temperature wall function was improved to calculate the accurate end-gas temperature for precise knock prediction. Then, Calculation results were verified by comparing with experiments. The results confirmed that the prediction of knock onset timing and location have good agreements with measured ones. Thus, it has been established that optimization of the Shell model and more precise prediction of wall heat flux improves the precision of knock onset timing.