Four dimensional visualization of highly transient fuel sprays by microsecond quantitative x ray tomography
An ultrafast x ray microtomography technique based on synchrotron x rays and a fast framing x ray detector was developed to reconstruct the highly transient sprays in four dimensions with microsecond temporal resolution in the near nozzle region. The time resolved quantitative fuel distribution allowed a realistic numerical fluid dynamic simulation with initial conditions based on the measurement, which demonstrates that the fuel has completed the primary breakup upon exiting the nozzle. The secondary breakup based simulation agrees well with the experimental fuel volume fraction distribution, which challenges most existing simulation assumptions and results.