Advances in Time-gated Ballistic Imaging for Studies of Atomizing Fuel Sprays

Sammanfattning: The transportation sector of today relies heavily on fossil fuels. This is undesirable both due to the finite nature of the fossil resources and to the effects of global warming. Therefore, there is a need to find alternative fuels and simultaneously develop combustion engines with higher efficiencies. This thesis describes the further development and application of ballistic imaging. Ballistic imaging is a laser based diagnostic technique designed to obtain information about the primary breakup of fuel sprays. It makes use of femtosecond laser pulses and very fast nonlinear optical devices to suppress noise generated by droplet scattering in shadowgraphy-styled images. This allows the interior if the primary breakup region to be imaged. With a better understanding of the dynamics involved when the contiguous liquid is dispersed into a spray, engines with higher efficiencies and lower engine-out emissions can be more rapidly designed.