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According to current trends in the energy market, heavy duty gas turbines are increasingly being used to fill gaps in the power energy supply and are less frequently operated in pure steady-state base load conditions. This tendency implies more rapid load ramps and is confirmed by utilities’ requirements for more operational flexibility in order to increase their net revenues. In order to assess the effects of such load variations on temperature gradients withstood by the various components, a series of simple correlations are derived that take in account key operating parameters of gas turbines. To this end, each blade and vane has been schematized as a compound of different portions to which specific values of cooling efficiency and gas temperature were assigned. This results in a simplified model of the engine allowing for the prediction of the temperature gradients on the base material of the critical zones of blades and vanes as a function of different cooling schemes. Method results can subsequently be exploited both to improve thermal design of hot gas path components, as well as to set up material testing campaigns targeting any specific duty cycle.Copyright © 2013 by ASME |
