This study presents a contribution to the development of a model for vegetable
oil droplets vaporization, with a particular focus on the influence of the exper
imental set-up for their use as fuel in diesel engines. Two systems were con
sidered: an open-environment system obtained through a hot gas flow, and a
closed-environment system. Vaporization was conducted under identical con
ditions, with the results subsequently compared. The findings indicate that,
for temperatures between 473 K and 673 K, droplets behaviour in both systems
presents only a heating and expansion phase. For temperatures above 673 K,
the behaviour of the droplets differs between the devices. In the open environ
ment device, a linear reduction in droplets diameter is observed following the
transient phase, suggesting stationary vaporization and enabling the calcula
tion of a vaporization constant and the well-known D2 law is respected. In the
closed-environment device, puffing, micro-explosions and gas ejections are
observed, and it is not possible to determine vaporization constant and D2 law
is not respected. The results demonstrate the necessity of developing a model
for the thermal decomposition of vegetable oil before attempting to create a
model for the vaporization of these oils. In order to achieve this, it is essential
to construct an experimental setup that more closely emulates the real condi
tions within the combustion chamber of a diesel engine, taking into account
the variables of pressure, temperature and the heating process.

Experimental Device, Vaporization, Vegetable Oil, Open Enclosure, Closed Enclosure, Diesel Engine