Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

A Comparison of Single-Entry and Multiple-Entry Casing Impingement Manifolds for Active Thermal Tip Clearance Control

Version 1 : Received: 28 January 2021 / Approved: 1 February 2021 / Online: 1 February 2021 (11:26:49 CET)
Version 2 : Received: 8 May 2021 / Approved: 10 May 2021 / Online: 10 May 2021 (11:57:18 CEST)

A peer-reviewed article of this Preprint also exists.

Dhopade, P.; Kirollos, B.; Ireland, P.; Lewis, L. A Comparison of Single-Entry and Multiple-Entry Casing Impingement Manifolds for Active Thermal Tip Clearance Control. Int. J. Turbomach. Propuls. Power 2021, 6, 10. Dhopade, P.; Kirollos, B.; Ireland, P.; Lewis, L. A Comparison of Single-Entry and Multiple-Entry Casing Impingement Manifolds for Active Thermal Tip Clearance Control. Int. J. Turbomach. Propuls. Power 2021, 6, 10.

Journal reference: Int. J. Turbomach. Propuls. Power 2021, 6, 10
DOI: 10.3390/ijtpp6020010

Abstract

In this paper we compare using computational fluid dynamics the aerothermal performance of two candidate casing manifolds for supplying an impingement-actuated active tip clearance control system for an aero-engine high-pressure turbine. The two geometries are (a) single-entry: an annular manifold fed at one circumferential location; (b) multiple-entry: a casing manifold split into four annular sectors, each sector supplied separately from an annular ring main. Both the single-entry and multiple-entry systems analysed in this paper are idealised version of active clearance control systems in current production engines. Aerothermal performance is quantitatively assessed on the basis of the heat transfer coefficient distribution, driving temperature difference for heat transfer between the jet and casing wall, and total pressure loss within the high-pressure turbine active clearance control system. We predict that the mean heat transfer coefficient (defined with respect to the inlet temperature and local wall temperature) of the single-entry active clearance control system is 77% greater than the multiple-entry system; primarily because the coolant in the multiple-entry case picks up approximately 40 K of temperature from the ring main walls, and secondarily because the average jet Reynolds number of impingement holes in the single entry system is 1.2 times greater than in the multiple entry system. The multiple-entry system exhibits many local hot and cold spots, depending on the position of the transfer boxes, while the single-entry case has a more predictable aerothermal field across the system. The multiple-entry feed system uses an average of 20% of the total available pressure drop, while the feed system for the single-entry geometry uses only 2% of the total available pressure drop. From the aerothermal results of this computational study, and in consideration of holistic aero-engine design factors, we conclude that a single-entry system is closer to an optimal solution than a multiple-entry system.

Subject Areas

impingement; heat transfer; manifold; tip clearance; active flow control; gas turbine

Comments (1)

Comment 1
Received: 10 May 2021
Commenter: Priyanka Dhopade
Commenter's Conflict of Interests: Author
Comment: Added a comparison to correlation and more details about CFD setup. 
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