Cracking the mystery of droplet evaporation

Curtin University scientists have modelled the effects of droplet size and velocity on evaporation to better understand the refining process of heavy oil.

Department of Chemical Engineering researcher Dr Monica Gumulya studied the hydrodynamics of liquid droplet evaporation on heated, solid spherical particles.

“How fast evaporation occurs is not actually known, and what parameters influence that are not known,” Dr Gumulya says.

Oil is classified as heavy or light depending on its density compared to water. Heavy oils have longer-chained molecules and are more difficult to process.

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CrazyNeutrino said:

Cracking the mystery of droplet evaporation

Curtin University scientists have modelled the effects of droplet size and velocity on evaporation to better understand the refining process of heavy oil.

Department of Chemical Engineering researcher Dr Monica Gumulya studied the hydrodynamics of liquid droplet evaporation on heated, solid spherical particles.

“How fast evaporation occurs is not actually known, and what parameters influence that are not known,” Dr Gumulya says.

Oil is classified as heavy or light depending on its density compared to water. Heavy oils have longer-chained molecules and are more difficult to process.

more…

Evaporation is a bastard of a thing to calculate. I’ve calculated it three times as part of my work at CSIRO, including once with droplets, and used a different method each time. The difficulty is due to reliably estimating the effect of free and forced convection in the air adjacent to the droplet. This air rapidly builds up a vapour pressure gradient that opposes the process of evaporation, the rate of evaporation then depends critically on how this vapour pressure gradient is removed. I ended up convinced that the best way to mathematically model evaporation is to measure it and then adjust the equations to fit the observations, eventually using a 50-50 hybrid of theory and observation.