A critical review on gas turbine cooling performance and failure analysis of turbine blades

This paper is an overview of one of the most important turbo-machineries, the gas turbine emphasizing the thermal performance and the failure analysis. It can be a pathway for further improvement of the performance and efficiency of the gas turbine, and the prevention of gas turbine units’ failures in future by identifying the root causes from previous failure case studies. The turbine performance depends on the cooling efficiency, and thus the thermal efficiency is affected by the cooling of the gas turbine blades. Different methods and strategies are being highlighted to improve the thermal performance and the cooling efficiency of the gas turbine. Cooling of the blades enhances the power output and thermal efficiency using the steam injection method. Nearly 60% efficiency can be achieved by adopting different cooling methods. The selection of the working fluid for gas turbines is dependent on the cycle, scale, and, application. For example, Supercritical CO2 can be a suitable working fluid for closed-cycle thermal power plants. However, the optimum selection is subjected to many other factors like economic, environmental, thermodynamic performance, possible layout, etc. that must be assessed carefully before installation in any particular field. Fuel selection in the fuel system of a gas turbine facilitates flexibility. Fuel selection also should be done considering the cycle, scale, and application as well as modes of operations, efficiency, availability, cost, and exhaust which can affect the environment. For instance, special fuels can be burnt in GT with large combustors. Besides the commonly used fuels like natural gas and diesel oil, some alternative fuel sources like C. inophyllum biodiesel, bio-ethanol, and many other fuels are also mentioned to emphasize the importance of these alternative, environment-friendly, and sustainable fuel sources for the future. The study of the failure of gas turbines also becomes critical, since the failure of a turbine engine unit comes with a high amount of economic loss. It also emphasizes the major reasons for failure and effective ways to prevent them under different working conditions. Several coating methods such as TBC (Thermal Barrier Coatings) and Aluminide coating can be adopted to resist the failure scenarios caused by oxidation and hot corrosion. Some modern coating techniques might prevent the fatigue and fretting failures. Deformations of gas turbine blades resulting from the extreme stress, thermal loads, and vibrational effects are major causes of the failure in gas turbines and Titanium, Inconel, and Nimonic 80A are regarded to be the most suitable material for blade construction. Here, the importance of blade material selection and ideal material for blades are elaborately discussed to enhance performance and minimize failure. © 2023 The Author(s)