Improvement of grain structure and mechanical properties of a land based gas turbine blade directionally solidified with liquid metal cooling process

2008 ◽  
Vol 24 (1) ◽  
pp. 100-106 ◽  
Author(s):  
A. Kermanpur ◽  
M. Mehrara ◽  
N. Varahram ◽  
P. Davami
Keyword(s):  
Mechanical Properties ◽  
Liquid Metal ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Grain Structure ◽  
Gas Turbine Blade ◽  
Directionally Solidified ◽  
Cooling Process ◽  
Liquid Metal Cooling

Life Prediction of Directionally Solidified Air Cooled HPT Gas Turbine Blade Used in a Supersonic Aircraft Using FEM

2013 ◽  
Author(s):  
S. Esakki Muthu ◽  
S. Dileep ◽  
S. Saji Kumar ◽  
D. K. Girish
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Operating Conditions ◽  
Test Facility ◽  
Time To Failure ◽  
Generation Process ◽  
Gas Turbine Blade ◽  
Directionally Solidified ◽  
Life Estimation ◽  
Supersonic Aircraft

Life estimation of Directionally Solidified (DS) MARM-247 HPT gas turbine blade used in a turbofan engine of a supersonic aircraft is presented. These blades were drafted into the engine as a replacement for the polycrystal (NIMONIC) blades since a more efficient, reliable and durable material with high strength and temperature resistance was required to further enhance the life of the turbine blade and the efficiency of the power generation process. The supersonic aircraft is having a repeated mission cycle of a fast acceleration from idle, a 1hr cruise at Mach 1.5 and a fast deceleration to idle. The mission cycle which is a repetition of acceleration, cruise and deceleration cycles can produce wide variety of complex loading conditions which can result in HCF, LCF and creep damage of the turbine blade. Empirical equation of the universal slope developed by Manson was used to estimate the damage component due to LCF. The cumulative stresses and strains due to creep as a function of time was determined using Time hardening rule. Creep data for MARM-247 was correlated using LMP to predict the lives to 1% of creep strain at worst possible combination of temperature and stress value. Damage due to creep per mission cycle was determined using Life fraction Rule proposed by Robinson and Taira. The vibration characteristics of the turbine blade were predicted using Modal analysis. Campbell diagram was plotted to ascertain whether any nozzle passing frequency fall within the working range of the blade. Harmonic analysis was carried out to evaluate the magnitude of the alternating stresses resulting from the blade vibrations at resonance during the acceleration and deceleration cycle. HCF life of the turbine blade was assessed using Goodman diagram. The total damage of the turbine blade per mission cycle due to the above loading was assumed as the combination of the individual damage due to fatigue and creep. Time to failure under combined creep and fatigue damage was estimated using linear damage rule. Non linear features of FEA tool ANSYS12.0 was exploited to calculate the stress distribution, creep, plastic and the total strain encountered by the turbine blade as a function of mission cycle time. The loading spectrum associated with the mission cycle which includes the temperature, gas pressure and the speed profiles were obtained from a sophisticated engine ground test facility which was configured to simulate actual engine operating conditions. The proposed method of cyclic life estimation using FEM was validated by performing various component and engine level tests. A good agreement was observed between the calculated and observed blade lives.

Mechanical Properties According to Heat Treatment for Gas Turbine Blade Material

2007 ◽  
Vol 26-28 ◽  
pp. 209-212
Author(s):  
Moon Young Kim ◽  
Sung Ho Yang ◽  
Kuk Hyun Song
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Hot Isostatic Pressing ◽  
Experimental Result ◽  
Gas Turbine Blade ◽  
Post Heat Treatment ◽  
Gas Turbine Blades

This work was studied for the changes of thermal properties on GTD-111 DS (Directional Solidification) gas turbine blade. In this study, gas turbine blades with 24,000~34,000 firing hours was used to get more effective result, gradually applied hot isostatic pressing (HIP) and post-heat treatment for these samples. In the latter steps, we observed changes of γ´ phase affected in material properties, and microhardness test was carried out to evaluate mechanical properties according to changes of γ´ fraction and shape. Experimental result shows, changes of γ´ fraction and shape were affected by HIP and post-heat treatment. And also mechanical properties changes such as micro-hardness related to γ´ phase. In this study, we explained changing transition of microstructure according to γ´ fraction distribution.

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