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@PHDTHESIS{DeLannoye:1044505,
author = {De Lannoye, Karen},
title = {{T}he tube furnace as a new bench scale experiment for
pyrolysis},
volume = {72},
school = {Wuppertal},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2025-03242},
isbn = {978-3-95806-839-1},
series = {Schriften des Forschungszentrums Jülich IAS Series},
pages = {ix, 70},
year = {2025},
note = {Dissertation, Wuppertal, 2024},
abstract = {Electrical cables are a potential source of fire in many
different application areas, ranging from residential
buildings to spacecrafts. The current state of the art
models for fire spread on a cable or cable tray are using a
prescribed spread rate. Many efforts have been made within
the research community, to enhance the understanding of
cable fires. Nevertheless, many challenges still remain [1].
In order to better understand the influence of certain
boundary conditions (e.g. composition and flow conditions of
the surrounding atmosphere), a new designed set-up for gram
scale pyrolysis experiments is proposed. In fire safety
science, the thermogravimetric analyser (TGA) and the cone
calorimeter are both often used for pyrolysis and combustion
experiments. The TGA allows examining milligram-scale
samples under well-defined boundary conditions, while the
cone calorimeter allows for larger (gram-scale) samples but
with less well known boundary conditions. Within this
thesis, experiments with polymethyl methacrylate (PMMA) are
conducted in the TGA and the cone calorimeter. In the TGA,
the effect of several different experiment and material
parameters on the pyrolysis behaviour is investigated.
Including, the effect of different sample colour and
different atmospheres is included in this study. In the cone
calorimeter, the effect of different sample colour is
studied. PMMA was chosen as a material since its fire
behaviour is often studied in the literature. The newly
designed experiment is based on the ISO-19700 standard for
the steady state tube furnace. The set-up consists of a tube
furnace which is combined with an online mass loss
measurement. The advantage of the new set-up is that it
provides well-defined boundary conditions, as well as
radially symmetric heating. The mass loss measurement is
enabled using a cantilever mechanism. This cantilever
connects the specimen in the oven with a load cell outside
the high temperature region of the oven. Additionally, the
set-up is connected to a gas analyser with CO, CO2 and O2
measurements. Temperatures at the in- and outside of the
set-up are recorded using K-type thermocouples. The
functionality of the balance is demonstrated by comparing
the mass loss rate of the balance with the rate obtained
from the measurements by the gas analyser. A very good
agreement was found between the results from the gas
analyser and the balance, showing the excellent
functionality of the new balance. A comparison between the
new device; the TGA and the cone calorimeter is done using
PMMA. A difference in mass loss rate and heat release rate
was found between black and transparent PMMA in the cone
calorimeter. This difference becomes larger for higher
external heat fluxes. It is believed that this might be due
to a difference in absorption coefficient for both
materials, however additional exiperiments would have to be
conducted to confirm this hypothesis. When comparing black
and transparent PMMA in the tube furnace no difference in
mass loss rate was found. This could indicate that the
involved heat transfer process in the tube furnace is less
dominated by radiation or this might be due to the lower
temperatures in the tube furnace. When comparing the mass
loss rate results of the tube furnace and the TGA, it was
found that changing the atmosphere from nitrogen to air has
a similar effect in both devices, namely the mass loss rate
starts earlier under air atmosphere. Additional experiments
should be considered to further compare the three devices.
The scale of the tube furnace does not allow to ignore heat
and mass transfer. Additionally, a temperature gradient is
present throughout the length of the furnace. This makes the
tube furnace a more complicated experiments than e.g. the
TGA, more experiments should be conducted to further
characterize the boundary conditions in the tube furnace. In
future, it should be considered to make a computational
model of the tube furnace which can be used to determine
kinetic parameters by inverse modelling. This would allow to
further evaluate the added value of the tube furnace to
predicting parameters needed for fire spread modelling.},
cin = {IAS-7},
cid = {I:(DE-Juel1)IAS-7-20180321},
pnm = {5111 - Domain-Specific Simulation $\&$ Data Life Cycle Labs
(SDLs) and Research Groups (POF4-511)},
pid = {G:(DE-HGF)POF4-5111},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
doi = {10.34734/FZJ-2025-03242},
url = {https://juser.fz-juelich.de/record/1044505},
}