The Science, Technology, and Implementation of TiAl Alloys in Commercial Aircraft Engines

2013 ◽  
Vol 1516 ◽  
pp. 49-58 ◽  
Author(s):  
B. P. Bewlay ◽  
M. Weimer ◽  
T. Kelly ◽  
A. Suzuki ◽  
P.R. Subramanian
Keyword(s):  
Titanium Aluminide ◽  
Turbine Blades ◽  
Aircraft Engine ◽  
Low Pressure ◽  
Major Advance ◽  
Commercial Aircraft ◽  
Tial Alloys ◽  
Low Pressure Turbine ◽  
Titanium Aluminide Alloy ◽  
History Of

ABSTRACTThe present article will describe the science and technology of titanium aluminide (TiAl) alloys and the engineering development of TiAl for commercial aircraft engine applications. The GEnxTM engine is the first commercial aircraft engine that is flying titanium aluminide (alloy 4822) blades and it represents a major advance in propulsion efficiency, realizing a 20% reduction in fuel consumption, a 50% reduction in noise, and an 80% reduction in NOx emissions compared with prior engines in its class. The GEnxTM uses the latest materials and design processes to reduce weight, improve performance, and reduce maintenance costs.GE’s TiAl low-pressure turbine blade production status will be discussed along with the history of implementation. In 2006, GE began to explore near net shape casting as an alternative to the initial overstock conventional gravity casting plus machining approach. To date, more than 40,000 TiAl low-pressure turbine blades have been manufactured for the GEnxTM 1B (Boeing 787) and the GEnxTM 2B (Boeing 747-8) applications. The implementation of TiAl in other GE and non-GE engines will also be discussed.

scholarly journals Surface Quality of Amilled Gamma Titaniumaluminide for Aeronautical Applications

2014 ◽  
Vol 5 (2) ◽  
pp. 60-65
Author(s):  
Grzegorz Radkowski ◽  
Jaroslaw Sep
Keyword(s):  
High Pressure ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Turbine Blades ◽  
Low Pressure ◽  
Aviation Industry ◽  
Gamma Titanium ◽  
Low Pressure Turbine ◽  
High Pressure Compressor ◽  
Pressure Compressor

Abstract Gamma titanium aluminides are an interesting alternative for nickel, iron or cobalt matrix superalloys. Due to the advantageous strength properties at high temperatures they can successfully replace superalloys in applications such as high pressure compressor blades, low pressure turbine blades, high pressure compressor case, low pressure turbine case. Milling is one of the processes that can be applied in the forming elements made from this type of alloys for the aviation industry. Research included the selection of tool, the process kinematics and the range of milling gamma titanium aluminide (Ti-45Al-5Nb-0.2B-0.2C) process parameters were carried out. Milling can be an effective method of forming of elements made of gamma TiAL in the range of processing parameters: vc = 20-70 m/min, ap = 0.3-0.7 mm, fz = 0.1- 0.45 mm/tooth. In the tests carried out the best results were obtained using a R300-016A20L- 08L milling cutter, S30T tool coating and in-cut milling.

In Situ Eddy-Current Testing on Low-Pressure Turbine Blades of Aircraft Engine

2012 ◽  
Vol 40 (4) ◽  
pp. 103388
Author(s):  
Gong-Jin Qi ◽  
Hong Lei ◽  
Gang-Qiang Fu ◽  
Peng Jing ◽  
Jun-Ming Lin
Keyword(s):  
Eddy Current ◽  
Turbine Blades ◽  
Aircraft Engine ◽  
Low Pressure ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Low Pressure Turbine

Cracks on the Roots of Turbine Blades of the Low-Pressure Turbine in a Steam Power Plant

2015 ◽  
Vol 52 (4) ◽  
pp. 214-225 ◽  
Author(s):  
E. Plesiutschnig ◽  
R. Vallant ◽  
G. Stöfan ◽  
C. Sommitsch ◽  
M. Mayr ◽  
...  
Keyword(s):  
Power Plant ◽  
Turbine Blades ◽  
Low Pressure ◽  
Steam Power ◽  
Steam Power Plant ◽  
Low Pressure Turbine

Noise Attenuation Potential Using Helmholtz Absorbers Integrated in Low Pressure Turbine Exit Guide Vanes and Turbine Exit Casing End Walls

2020 ◽  
Author(s):  
Manuel Zenz ◽  
Loris Simonassi ◽  
Philipp Bruckner ◽  
Simon Pramstrahler ◽  
Franz Heitmeir ◽  
...  
Keyword(s):  
Suction Side ◽  
Aircraft Engine ◽  
Low Pressure ◽  
Flow Channel ◽  
Operating Conditions ◽  
Noise Attenuation ◽  
Beneficial Result ◽  
Guide Vanes ◽  
Acoustic Liners ◽  
Low Pressure Turbine

Abstract To further reduce the noise emitted from modern aircrafts, every possibility has to be taken into account. Acoustic liners are successfully used in the inlet or the bypass duct of aircraft engines to mitigate the noise emitted by the fan. Due to the rough environment (high temperature, flow velocity, higher order duct modes), the exhaust duct is of limited use concerning the application of acoustic liners. It is well known that the last stage low pressure turbine (LPT) has a dominant influence onto the emitted noise of an aircraft engine especially at low load conditions such as approach. A noise reduction in this area could lead to a beneficial result of decreasing the noise content which is directly emitted in the environment. This paper is about noise attenuation using Helmholtz absorbers in various parts of a turbine exit casing (TEC). These single degree of freedom absorbers have been integrated in turbine exit guide vanes (TEGVs), with the openings on the vanes suction side, as well as in the inner and outer duct end walls. Different absorber neck diameters were investigated and combined with different vane designs. The vane designs studied included a state of the art set-up as well as vanes with a lean. Test runs were performed with altered combinations of vanes and end walls under engine relevant operating conditions in a subsonic test turbine facility for aerodynamic, aeroacoustic and aeroelastic investigations (STTF-AAAI) located at the Institute of Thermal Turbomachinery and Machine Dynamics at Graz University of Technology. Comparisons between all these setups and the respective hard wall reference cases were done. The resulting sound pressure levels as well as sound power levels of all investigated combinations are listed and compared concerning each configurations noise attenuation potential. Additionally, the flow field downstream of every setup is analysed if the aerodynamic behaviour is changing. The investigated operating point is the noise certification point Approach (APP) which is of high importance because of the high acoustical impact onto the environment around airports during the landing procedure of an aircraft. The acoustical data has been obtained by using flush mounted condenser microphones located downstream of the TEC. The whole test section was rotated over 360 deg around the flow channel. To detect if the aerodynamical behaviour changes by including openings into the flow channel end walls as well as into the vanes, aerodynamic measurements have been performed downstream of the TEC. The aerodynamical data was obtained by using an aerodynamic five-hole-probe (5HP) as well as a trailing edge probe.

Analysis on High Rates of Scaling and Salt Accumulation of 600MW Supercritical once-through Boiler

2012 ◽  
Vol 166-169 ◽  
pp. 620-626
Author(s):  
Xiao Ni Zhang ◽  
Xian Min Li ◽  
Chang Ming Li
Keyword(s):  
Turbine Blades ◽  
Low Pressure ◽  
Fossil Plants ◽  
Salt Accumulation ◽  
Accelerated Corrosion ◽  
Low Pressure Turbine ◽  
Salt Deposition ◽  
Boiler Units ◽  
Salt Deposits ◽  
Flow Accelerated Corrosion

The chemistry check-ups were reviewed in the first maintenance of 600 MW supercritical once-through boiler units in Henan. Several problems were found: (1) high rates of scaling on the waterwall and economizer; (2) high rates of salt deposition on the turbine blades; (3) the formation of salt deposits on blades were complicated; (4) corrosion of low pressure turbine blades in period of maintenance was a universal phenomenon; (5) FAC (flow-accelerated corrosion) were most frequent in HP heaters and HP drain lines in most fossil plants. The reasons have been analyzed and the suggestions have been provided.

scholarly journals Flutter Mechanisms in Low Pressure Turbine Blades

1998 ◽  
Author(s):  
M. Nowinski ◽  
J. Panovsky
Keyword(s):  
Research Effort ◽  
Turbine Blades ◽  
Low Pressure ◽  
Design Parameters ◽  
Computational Techniques ◽  
Influence Coefficient ◽  
Low Pressure Turbine ◽  
Blade Flutter ◽  
Euler Methods ◽  
Annular Cascade

The work described in this paper is part of a comprehensive research effort aimed at eliminating the occurrence of low pressure turbine blade flutter in aircraft engines. The results of fundamental unsteady aerodynamic experiments conducted in an annular cascade are studied in order to improve the overall understanding of the flutter mechanism and to identify the key flutter parameters. In addition to the standard traveling wave tests, several other unique experiments are described. The influence coefficient technique is experimentally verified for this class of blades. The beneficial stabilizing effect of mistuning is also directly demonstrated. Finally, the key design parameters for flutter in low pressure turbine blades are identified. In addition to the experimental effort, correlating analyses utilizing linearized Euler methods demonstrate that these computational techniques are adequate to predict turbine flutter.

Flutter of Low Pressure Turbine Blades With Cyclic Symmetric Modes: A Preliminary Design Method

2004 ◽  
Vol 126 (2) ◽  
pp. 306-309 ◽  
Author(s):  
Robert Kielb ◽  
Jack Barter ◽  
Olga Chernycheva ◽  
Torsten Fransson
Keyword(s):  
Mode Shape ◽  
Design Method ◽  
Turbine Blades ◽  
Current Method ◽  
Low Pressure ◽  
Mode Shapes ◽  
Preliminary Design ◽  
Complex Mode ◽  
Low Pressure Turbine ◽  
Reduced Frequency

A current preliminary design method for flutter of low pressure turbine blades and vanes only requires knowledge of the reduced frequency and mode shape (real). However, many low pressure turbine (LPT) blade designs include a tip shroud that mechanically connects the blades together in a structure exhibiting cyclic symmetry. A proper vibration analysis produces a frequency and complex mode shape that represents two real modes phase shifted by 90 deg. This paper describes an extension to the current design method to consider these complex mode shapes. As in the current method, baseline unsteady aerodynamic analyses must be performed for the three fundamental motions, two translations and a rotation. Unlike the current method work matrices must be saved for a range of reduced frequencies and interblade phase angles. These work matrices are used to generate the total work for the complex mode shape. Since it still only requires knowledge of the reduced frequency and mode shape (complex), this new method is still very quick and easy to use. Theory and an example application are presented.

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