Special Issue "Secondary Air Systems in Gas Turbine Engines"

A special issue of Aerospace (ISSN 2226-4310).

Deadline for manuscript submissions: 28 August 2018

Special Issue Editor

Guest Editor
Dr. Erinc Erdem

School of Engineering, University of Glasgow, Glasgow G12 8QQ, Scotland, UK; TUSAS Engine Industries (TEI), Esentepe Mah. Cevreyolu Bulvari no.356, Eskisehir, Turkey
Website | E-Mail
Interests: aerothermal analysis; turbomachinery; modelling and simulation; ground testing; measurement techniques; propulsion

Special Issue Information

Dear Colleagues,

Modern gas turbine engines are presently being pushed to the limits of thermal efficiency, owing to recent advancements in materials and cooling technologies. The hot section of a gas turbine engine works above the limits of material capabilities. Consequently, there is a high demand for cooling and sealing to assure safe and sound operation throughout the operational envelope of an engine. Secondary Air Systems (SAS) play a significant role in gas turbine engines to accomplish reliable operation of the individual modules as well as the whole engine. Main functions of SAS are to provide cooling flow to engine components, to seal bearing chambers (sumps) and to control bearing axial loads. Being a functional discipline, SAS owns the airflow that is essentially the primary flowpath.

Traditionally, the design of secondary air systems utilized industrial friendly “one-dimensional modeling” for both compressible internal rotating/non-rotating fluid flow and heat transfer. Many correlations were developed to model/compute the flows with reasonable accuracy, taking into account of heat pickups on the way in flow circuits. Testing is an integral part of the design process comprising of flow testing of components, module testing and whole engine testing; providing essential data to characterize specific flow elements and circuits.

This collection invites papers that address the areas of SAS in gas turbine engines encompassing aviation, power generation and industrial applications. Of interest are papers that address novel approaches in flow network modeling, contemporary modeling and experimental efforts in rotor-stator/ rotor-rotor cavities, windage measurements and predictions, advanced flow network modeling to include transient behaviors, advanced sealing technologies, axial load control strategies, rim sealing developments and sump pressurization aspects.

Dr. Erinc Erdem
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Aerospace is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 550 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


  • Gas turbine engines
  • Secondary air systems
  • Gas turbine sealing technologies
  • One-dimensional flow network modeling
  • Rotor-stator/rotor-rotor cavities
  • Compressible internal flows
  • Heat transfer Gas turbine engine testing

Published Papers (1 paper)

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Open AccessArticle Numerical Investigation on Windback Seals Used in Aero Engines
Aerospace 2018, 5(1), 12; doi:10.3390/aerospace5010012
Received: 16 November 2017 / Revised: 4 January 2018 / Accepted: 12 January 2018 / Published: 20 January 2018
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Seals are considered one of the most important flow elements in turbomachinery applications. The most traditional and widely known seal is the labyrinth seal but in recent years other types like the brush or carbon seals were introduced since they considerably reduce the
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Seals are considered one of the most important flow elements in turbomachinery applications. The most traditional and widely known seal is the labyrinth seal but in recent years other types like the brush or carbon seals were introduced since they considerably reduce the sealing air consumption. When seals are used for sealing of aero engine bearing chambers they are subjected to high “bombardment” through oil particles which are present in the bearing chamber. These particles mainly result from the bearings as a consequence of the high rotational speeds. Particularly when carbon or brush seals are used, problems with carbon formation (coking) may arise when oil gets trapped in the very tight gap of these seals. In order to prevent oil migration into the turbomachinery, particularly when the pressure difference over a seal is small or even negligible, significant improvement can be achieved through the introduction of so called windback seals. This seal has a row of static helical teeth (thread) and below this thread a scalloped or smooth shaft section is rotating. Depending on the application, a windback seal can be used alone or as a combination with another seal (carbon, brush or labyrinth seal). A CFD analysis carried out with ANSYS CFX version 11 is presented in this paper with the aim to investigate this seal type. The simulations were performed by assuming a two-phase flow of air and oil in the bearing compartment. Design parameters like seal clearance, thread size, scallop width, were investigated at different operating conditions. Full article
(This article belongs to the Special Issue Secondary Air Systems in Gas Turbine Engines)

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