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Numerical modelling of pressure rise combustion for reducing emissions of future civil aircraft

This work assesses the feasibility of designing and implementing the wave rotor
(WR), the pulse detonation engine (PDE) and the internal combustion wave
rotor (ICWR) as part of novel Brayton cycles able to reduce emissions of future
aircraft. The design and evaluation processes are performed using the
simplified analytical solution of the devices as well as 1D-CFD models. A code
based on the finite volume method is built to predict the position and
dimensions of the slots for the WR and ICWR. The mass and momentum
equations are coupled through a modified SIMPLE algorithm to model
compressible flow. The code includes a novel tracking technique to ensure the
global mass balance. A code based on the method of characteristics is built to
predict the profiles of temperature, pressure and velocity at the discharge of the
PDE and the effect of the PDEs array when it operates as combustion chamber
of gas turbines. The detonation is modelled by using the NASA-CEA code as a
subroutine whilst the method of characteristics incorporates a model to capture
the throttling and non-throttling conditions obtained at the PDE's open end
during the transient process. A medium-sized engine for business jets is
selected to perform the evaluation that includes parameters such as specific
thrust, specific fuel consumption and efficiency of energy conversion. The ICWR
offers the best performance followed by the PDE; both options operate with a
low specific fuel consumption and higher specific thrust. The detonation in an
ICWR does not require an external source of energy, but the PDE array
designed is simple. The WR produced an increase in the turbine performance,
but not as high as the other two devices. These results enable the statement
that a pressure rise combustion process behaves better than pressure
exchangers for this size of gas turbine. Further attention must be given to the
NOx emission, since the detonation process is able to cause temperatures
above 2000 K while dilution air could be an important source of oxygen.

Identiferoai:union.ndltd.org:CRANFIELD1/oai:dspace.lib.cranfield.ac.uk:1826/9259
Date04 1900
CreatorsMaterano Blanco, Gilberto Ignacio
ContributorsSavill, Mark
PublisherCranfield University
Source SetsCRANFIELD1
LanguageEnglish
Detected LanguageEnglish
TypeThesis or dissertation, Doctoral, PhD
Rights© Cranfield University 2014. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright owner.

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