Thermo-Structural Analysis of Carbon Fibre-Ni Based Super Alloy Composite Employed in Gas Turbines

Abstract

A computational analysis was carried out on two different materials of turbine blades, namely Inconel MA754 and Nimonic 80A, in order to determine their structural and thermal properties at elevated temperatures. Long carbon fibers of uniform length were used and deposited at varying thicknesses ranging from 1 mm to 4 mm, on the top surface of turbine blades and then analyzed for its performance. It is seen that the carbon fibers (IM10) embedded in the super alloys drastically improve the load bearing parameters of the configurations being analyzed. The improvement in structural load carrying ability is a result of higher Young's modulus primarily. Subsequent analysis with higher volume fraction of the fibers indicated saturation of performance at about 70 % volume fraction for 4 mm fibers and significant improvement beyond it for the 1 mm fibers. With improvement in the load bearing characteristics the blade with fibers embedded into a tube like structure at 3 sections were configured and A thermal analysis of the same underscores the effectiveness of the 4 mm fibers in undergoing much reduced principal strains than other configurations. This is seen to be a result of insulation of the top surface from increase in temperature, which significantly reduces the thermal expansion, especially at the free end. This is in contrast to other configurations, where the low volume fraction of fibers resulted in high principal strain.