Assessment of Surface Treatment Effectiveness and Degradation by Direct Field Measurement

2007 ◽  
Author(s):  
Curtis A. Rideout ◽  
Scott J. Ritchie
Keyword(s):  
Residual Stresses ◽  
Surface Treatment ◽  
Treatment Effectiveness ◽  
Aerospace Materials ◽  
Single Measurement ◽  
Efficient Manner ◽  
Turbine Engine ◽  
Relaxation Effects ◽  
Critical Components ◽  
Induced Changes

The ability to detect and quantify beneficial surface and subsurface residual stresses, and operational damage in aerospace materials/structures in a reliable and efficient manner presents significant challenges to existing nondestructive inspection technologies. Induced Positron Analysis (IPA) has demonstrated the ability to nondestructively quantify shot peening/surface treatments and relaxation effects in single crystal superalloys, steels, titanium and aluminum with a single measurement as part of a National Science Foundation SBIR program and in projects with commercial companies. IPA measurement of surface treatment effects provides a demonstrated ability to quantitatively measure initial treatment effectiveness along with the effect of operationally induced changes over the life of the treated component. Use of IPA to nondestructively quantify surface and subsurface residual stresses in turbine engine materials and components has the potential to significantly improve the understanding at the microscale level the effects of surface coatings and treatments on the durability and fatigue life of critical components.

Simplified Design of Combustion Chamber for Small Gas Turbine Applications

2005 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Design Procedure ◽  
Design Guidelines ◽  
Radial Temperature ◽  
Turbine Engine ◽  
Design Methodologies ◽  
Critical Components ◽  
Discrete Manner ◽  
Centerline Temperature

The combustion chamber of gas turbine unit is one of the most critical components to be designed. Scanning through literature reveals that the design methodologies for combustion chamber are available in a discrete manner and there exist a need to compile this information and evolve a systematic design procedure for combustion chamber. The present paper is an attempt towards presenting such a complete design methodology of combustion chamber for small gas turbine applications. The combustion chamber for the 20 kW gas turbine engine has been designed and fabricated as per these summarized design guidelines then checked for the axial and radial temperature profiles as well as liner wall temperatures, experimentally. The liner wall temperatures achieved is in the vicinity of 300°C when centerline temperature is of the order of 1300°C. This adequately validates the design methodologies proposed in this paper.

scholarly journals A Computer Code for Gas Turbine Engine Weight and Disk Life Estimation

2004 ◽  
Vol 126 (2) ◽  
pp. 265-270 ◽  
Author(s):  
Michael T. Tong ◽  
Ian Halliwell ◽  
Louis J. Ghosn
Keyword(s):  
Aircraft Engine ◽  
Computer Code ◽  
Design Stage ◽  
Aerospace Materials ◽  
Turbine Engine ◽  
Prediction Module ◽  
Weight Calculation ◽  
Turbine Disks ◽  
Insight Into ◽  
Engine Life

Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. In this paper, the major enhancements to NASA’s engine-weight estimate computer code (WATE) are described. These enhancements include the incorporation of improved weight-calculation routines for the compressor and turbine disks using the finite difference technique. Furthermore, the stress distribution for various disk geometries was also incorporated, for a life-prediction module to calculate disk life. A material database, consisting of the material data of most of the commonly used aerospace materials, has also been incorporated into WATE. Collectively, these enhancements provide a more realistic and systematic way to calculate the engine weight. They also provide additional insight into the design tradeoff between engine life and engine weight. To demonstrate the new capabilities, the enhanced WATE code is used to perform an engine weight/life tradeoff assessment on a production aircraft engine.

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