Question

It is important to model spray break-up accurately. How does faster spray break-up affect vaporization rates? How does this affect non-premixed combustion? How does this affect premixed combustion?

Answer 1

Yes it is important to accurately model Spray break up Because that defines the combustion time. A good breakup means finer droplets of fuel which enables a good combustion

Diesel engines find widespread applications in many industries, including transportation,agriculture, and power generation, among others. The latest developments in fuel injection strategy efficiency tend to focus on the injection rate to increase fuel mixing efficiency and reduce emissions. The duration of combustion decreases as the mixture of air and fuel improves, meaning that combustion occurs faster. Conversely, under a low initial injection rate,
the initial atomization of the fuel and premixing are not good. The slow initial injection fuel droplets will combine with faster fuel droplets, which will result in a larger droplet size that yields a poor spray breakup. The combustion period will then be longer as more time is required to inject the fuel to atomize and evaporate it for combustion.

Non Premixed

The inclusion of cavitation and turbulence enhances the primary breakup process, causing smaller droplet sizes, decrease in liquid penetration, and increase in radial dispersion. In Non premixed Break up modeling is of high importance as described above

Pre mixed combustion

In premixed the fuel is mixed to the air before it reaches the combustion chamber. and there is enough time for the fuel to mix up with air. But ignition nucleation formation is slightly complicated in premixed fuel, Also the components need to be designed to handle the fuel corrosion charecteristics.