INFLUENCE OF FLOW COEFFICIENT ON INGRESS THROUGH TURBINE RIM SEALS

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Rim seals are critical in terms of limiting the temperature
of highly-stressed engine components but function with a
penalty to the power output and contribute to entropy gain
stemming from mixing losses in the turbine. Ingress through
rim seals is influenced by the presence of rotor blades and
stator vanes, and the mainstream flow coefficient in the
annulus that determines the corresponding swirl.
This paper presents an experimental study of ingress
upstream and downstream of the rotor disc in a 1.5-stage rig
with double radial clearance rim seals. Two rotor discs were
used, one with blades and one without, and two platforms
were used downstream of the rotor, one with vanes and one
without. Tests were conducted at two rotational speeds and a
range of flow conditions was achieved by varying the annulus
and sealing mass flow rates. Concentration effectiveness,
swirl and steady pressure measurements separated, for the
first time, the influence of the blades and vanes on ingress
over a wide range of flow conditions. Measurements on the
downstream stator platform provide added insight into the
complex interaction between the egress and the mainstream.
Measurements of unsteady pressure revealed the presence of
large-scale structures, even in the absence of blades. The
number and speed of the structures was shown to depend on
the flow coefficient and the purge flow rate.
Original languageEnglish
Title of host publicationASME Turbo Expo 2021 Turbomachinery Technical Conference and Exposition
PublisherAmerican Society of Mechanical Engineers (ASME)
Publication statusAcceptance date - 16 Mar 2021

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