2134/22317
Praveen Elango
Praveen
Elango
Duncan Walker
Duncan
Walker
An investigation of flush off-takes for use in a cooled cooling air system
Loughborough University
2016
untagged
Engineering not elsewhere classified
2016-08-31 09:14:37
Conference contribution
https://repository.lboro.ac.uk/articles/conference_contribution/An_investigation_of_flush_off-takes_for_use_in_a_cooled_cooling_air_system/9221225
The design and evaluation of off-takes
has traditionally focused on increasing ram
pressure recovery with little consideration
given to flow uniformity. Preliminary studies
on a proposed cooled cooling air system for a
large aero gas turbine indicated that the offtake
represented a weak point in the design
with the non-uniformities it generated
negatively affecting system performance. High
levels of diffusion and a uniform flow are
required to minimise loss and to maximise the
effectiveness of the downstream heat
exchanger. This paper presents a numerical
and experimental parametric study of parallel
wall flush off-takes with focus placed on the
quality of the downstream flow and its
uniformity. A realisable k-omega turbulence
closure was employed with a standard wall
function to examine the pressure recovery
and uniformity of flush off-takes. The
performance of the off-take was investigated
with different inflow boundary layer
thicknesses in conjunction with changes in
various design parameters. The current
investigation highlights that there exists a
direct trade-off between the diffusion and
uniformity that can be achieved by a flush offtake.
Nevertheless, the work provides an
improved understanding of how each
performance parameters can be maximised
with respect to uniformity and this knowledge
is currently being applied to the development
of an optimal off-take design.