Abstract
Gas turbine performance is closely linked to the turbine inlet temperature, which is limited by the turbine guide vanes ability to withstand the massive thermal loads. Thus, steam cooling has been introduced as an advanced cooling technology to improve the efficiency of modern high-temperature gas turbines. This study compares the cooling performance of compressed air and steam in the renowned radially cooled NASA C3X turbine guide vane, using a numerical model. The conjugate heat transfer (CHT) model is based on the RANS-method, where the shear stress transport (SST) k−ω model is selected to predict the effects of turbulence. The numerical model is validated against experimental pressure and temperature distributions at the external surface of the vane. The results are in good agreement with the experimental data, with an average error of 1.39% and 3.78%, respectively. By comparing the two coolants, steam is confirmed as the superior cooling medium. The disparity between the coolants increases along the axial direction of the vane, and the total volume average temperature difference is 30 K. Further investigations are recommended to deal with the local hot-spots located near the leading- and trailing edge of the vane.
Highlights
Computation 2021, 9, 63. https://Growing awareness of global warming and stringent regulations has led to a shift in the global energy market towards renewable energy such as solar, wind and hydropower. renewable energy production is increasing, it still accounted only for 14% of the global energy market in 2019 compared to fossil fuels, approximately 80% [1]
The primary objective of this study is to investigate the effects of replacing compressed air with steam as a coolant in a turbine guide vane
The results show that mesh independence is achieved at approximately 1.4 million cells
Summary
Growing awareness of global warming and stringent regulations has led to a shift in the global energy market towards renewable energy such as solar, wind and hydropower. The actual cycle involves further losses like mechanical, aerodynamical, heat release, and pressure drop, reducing the gas turbine efficiency and increasing environmental impacts. Among the most influential parameters that affect the efficiency is the turbine inlet temperature (TIT) [5] This temperature is constrained by the turbine vanes and blades ability to withstand the arduous operating conditions. The famous NASA C3X turbine guide vane [11] has been used in numerous studies to investigate different cooling techniques. The primary objective of this study is to investigate the effects of replacing compressed air with steam as a coolant in a turbine guide vane
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