A study of fuel spray simulations under non-reacting condition in a constant volume chamber by LES

摘要

For engine analysis, an accurately capturing physics of fuel injection, spray breakup and spray vaporization are needed. To obtain the jet spray characteristics in more detail, the spray bomb simulations are a better method to isolate the spray patterns. In the research, the experiments of spray bomb with a constant volume chamber without the moving boundaries are chosen to be a test case. The commercial code ANSYS Forte is used to simulate fuel sprays and Large Eddy Simulation techniques (LES) with a dynamic structure model are employed to capture flow fields and internal spray structures. The simulated spray results are validated with available experimental data from Sandia National Laboratories USA using n-heptane fuel under non-reacting conditions. The predicted results of liquid and vapor penetration length are presented by LES simulations. The simulated vapor penetration is over-predicted in the early stage and matched well with experimental data after t = 0.75 ms. The increase of ambient pressure has made the decrease of the vapor and liquid penetration length. The transient behaviors of temperature and velocity are also captured in this study.