Innovative Measurement Techniques for a Cooled Turbine Casing Operating at Engine Representative Thermal Conditions

Abstract

To optimize the efficiency of modern aero-gas turbine engines the turbine tip clearances must be tightly controlled so as to minimize leakage losses. In addition, the clearance control system must be able to respond with sufficient rapidity to engine thermal transients. One method of achieving turbine tipclearance control is to manipulate the turbine casing temperature, and thereby radial growth, by convective cooling. The consequent clearance control system represents a particularly complex thermo-mechanical design problem. The current experimental study aims to simulate the heat loads to which the internal surfaces of the casing are typically exposed and to characterize the radial and axial displacement of the free-body casing under varying external cooling conditions. Importantly, the newly commissioned test facility allows a realistic assessment of the casing cooling impact on dimensional control, and also the rapid characterization and comparison of different concepts. The test facility comprises a model of a high-pressure/intermediate-pressure * Address all correspondence to this author. turbine casing with generic impingement cooling manifolds. A radiant heater is mounted within the casing model such that a near-uniform heat flux condition can be established on the casing wall inner surface. Extensive surface mounted thermocouples are welded to the casing wall to monitor variations in metal temperature. Radial and axial displacement of the casing is monitored using laser triangulation and linear variable differential transformer sensors. Experiments have been conducted over a range of heat load conditions and with engine representative levels of casing cooling applied. Importantly, the new test facility allows for the characterization of the casing cooling system as a whole. NOMENCLATURED displacement. E axial expansion. l casing axial length. r HP casing radius. Downloaded From: http://proceedings.asmedigitalcollection.asme.org/ on 05/29/2015 Terms of Use: http://asme.org/terms RDG reading. FSO full scale output.

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

“…The impingement manifold is either a single 360° annulus or two 180° sectors. Examples of single-entry casing impingement manifolds include the MTU aero-engine shown in Figure 1, the GE CF6-6 architecture shown in Figure 2 and the enginescale experiments of Dann et al [14].…”

Identification of engine faults based on acoustic emission signals using a 1DCNN-ViT ensemble model

“…The most critical load-bearing component of the engine is the intermediate case, which has a complex structure, thin wall and large area. Under aerodynamic, mechanical and thermal loads, the intermediate case is prone to crack, impact and rubbing, which directly affect the performance of the engine [2]. Therefore, it is urgent to focus on condition monitoring and fault diagnosis of the engine.…”

Experimental and Numerical Investigation of Annular Casing Impingement Arrays for Faster Casing Response

“…The majority of studies related to tip clearance control for aero-engines use scaled down facilities with cold flow, coupled with computational fluid dynamics (CFD) [8,9] to investigate case cooling. However, the casing transient response that influences tip clearance is also heavily dependent on the heat transferred to the casing inner surface.…”