CFD modeling of cargo compartment fire extinguishing system onboard electric aircraft
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Today, when an aircraft is to be certified and approved to ensure safe flight, a
series of physical tests of safety critical systems and components are carried out.
Among these systems is the fire suppression system for the cargo compartment of
the aircraft. The existing fire extinguishing system designs depend primarily on
experience and physical tests. These tests are both costly and time consuming
and usually end up with the systems being over dimensioned to ensure they meet
the requirements for certification. The aviation industry has seen the potential in
applying computational fluid dynamics (CFD) simulation as a scientific design tool
for these systems, in order to reduce the number, and thus the cost, of physically
performed tests.
The objective of this thesis is to develop a first CFD model of the cargo compartment
fire extinguishing system. The model can then be adjusted in terms of parameters
and design to optimize the system efficiency before certification testing.
The modeling of the fire extinguishing system is divided into two separate models;
one for the discharge bottle and piping system, and one for the cargo compartment.
The Halon outlet parameters from the piping system are then used as inlet
parameters to the cargo compartment.
The cargo compartment is simulated for four configurations where the inlet flow
is varied between being straight or angled and with or without simplified discharge
nozzles. The simulations show that an angled discharge of Halon is preferred because
it spreads Halon more evenly compared to a straight discharge flow. Among the
angled inlet flow and nozzles, 90 degree nozzles provide the highest degree of coverage
by having the most probes that detect Halon. It is also this nozzle design that best
mimics those designs provided by nozzle suppliers.
Beskrivning
Ämne/nyckelord
CFD, firex, firex agent, Halon, single-phase, multiphase, electric airplane, aircraft development