State-of-the-Art Cooling Technology for a Turbine Rotor Blade (original) (raw)

Recent studies in turbine blade cooling

International Journal of Rotating Machinery, 2004

Gas turbines are used extensively for aircraft propulsion, land-based power generation, and industrial applications. Developments in turbine cooling technology play a critical role in increasing the thermal efficiency and power output of advanced gas turbines. Gas turbine blades are cooled internally by passing the coolant through several rib-enhanced serpentine passages to remove heat conducted from the outside surface. External cooling of turbine blades by film cooling is achieved by injecting relatively cooler air from the internal coolant passages out of the blade surface in order to form a protective layer between the blade surface and hot gas-path flow. For internal cooling, this presentation focuses on the effect of rotation on rotor blade coolant passage heat transfer with rib turbulators and impinging jets. The computational flow and heat transfer results are also presented and compared to experimental data using the RANS method with various turbulence models such as k-ε, and second-moment closure models. This presentation includes unsteady high free-stream turbulence effects on film cooling performance with a discussion of detailed heat transfer coefficient and film-cooling effectiveness distributions for standard and shaped film-hole geometry using the newly developed transient liquid crystal image method.

Recent Development in Turbine Blade Film Cooling

International Journal of Rotating Machinery, 2001

Gas turbines are extensively used for aircraft propulsion, land-based power generation, and industrial applications. Thermal efficiency and power output of gas turbines increase with increasing turbine rotor inlet temperature (RIT). The current RIT level in advanced gas turbines is far above the .melting point of the blade material. Therefore, along with high temperature material development, a sophisticated cooling scheme must be developed for continuous safe operation of gas turbines with high performance. Gas turbine blades are cooled internally and externally. This paper focuses on external blade cooling or so-called film cooling. In film cooling, relatively cool air is injected from the inside of the blade to the outside surface which forms a protective layer between the blade surface and hot gas streams. Performance of film cooling primarily depends on the coolant to mainstream pressure ratio, temperature ratio, and film hole location and geometry under representative engine f...

IJERT-External and Internal Cooling Techniques in a Gas Turbine Blade -An Overview

International Journal of Engineering Research and Technology (IJERT), 2021

https://www.ijert.org/external-and-internal-cooling-techniques-in-a-gas-turbine-blade-an-overview https://www.ijert.org/research/external-and-internal-cooling-techniques-in-a-gas-turbine-blade-an-overview-IJERTV10IS080055.pdf Gas turbine engines are widely used in propulsion of aircraft and power generation. The thermal efficiency and power output of these engines predominantly depend upon the turbine inlet temperature (TIT). Increase or decrease in TIT affects the efficiency and power output to a great extent. Gas turbine engines currently operate at TIT ranging from 1200°C to 1500°C which is way above the melting point of blade material. Safe operation of these engines at elevated temperatures have been made possible by efficient cooling of blades, protection of blade surfaces by application of thermal barrier coatings (TBC) and advancement in blade metallurgy. Due to rapid economic and industrial growth, engines with the capability to operate at higher TIT would be required in future. Also, the metallurgy of the blade and thermal barrier coatings are required to be developed further to ensure reliable operation under harsh conditions. Different blade cooling techniques and the influence of various parameters on the effectiveness have been discussed in the literature. This paper aims to holistically address the various facets of turbine blade cooling and its operational parameters as available in the literature.

Cooling of Rotating Turbine Blades – A Novel Approach

2020

A B S T R A C T Gas turbines are required to function at a higher temperature for better thermal efficiency hence cooling of rotating blades of gas turbines is very essential for longevity and more efficient operations. In order to achieve the same film cooling was employed injecting cold air into the bulk fluid boundary layer. The cool air spreads over the blade material surface and isolates the surface from getting excessive heated. Although a volume of work has been already done on the same but under static condition but in practice since the blade would be rotating with certain speed hence it was required to study the cooling effectiveness under dynamic situation. Simulation study was done providing a rotation at two different rpm and it was observed that with backward injection of cooling air, cooling effectiveness, corelated in terms of area covered was much better than the forward one. It also indicated that the effectiveness decreases with increase in rpm as the time availab...

External and Internal Cooling Techniques in a Gas Turbine Blade - An Overview

International journal of engineering research and technology, 2021

Gas turbine engines are widely used in propulsion of aircraft and power generation. The thermal efficiency and power output of these engines predominantly depend upon the turbine inlet temperature (TIT). Increase or decrease in TIT affects the efficiency and power output to a great extent. Gas turbine engines currently operate at TIT ranging from 1200°C to 1500°C which is way above the melting point of blade material. Safe operation of these engines at elevated temperatures have been made possible by efficient cooling of blades, protection of blade surfaces by application of thermal barrier coatings (TBC) and advancement in blade metallurgy. Due to rapid economic and industrial growth, engines with the capability to operate at higher TIT would be required in future. Also, the metallurgy of the blade and thermal barrier coatings are required to be developed further to ensure reliable operation under harsh conditions. Different blade cooling techniques and the influence of various par...

Internal Blade Cooling Technology on Gas Turbines

Cooling technologies are a major issue in gas turbine devices. Certain parts of them undergo high variations of temperature and, by a consequence, need to be efficiently cooled in order to avoid serious damages.

Analysis of combined convective and film cooling on an existing turbine blade

To support gas turbine operators, NLR is developing capabilities for life assessment of hot engine components. As a typical example the first rotor blades of the high pressure (HP) turbine of the F-100-PW-220 military turbofan will be discussed. For these blades tools have been developed to derive the blade temperature history from flight data obtained from F-16 missions. The resulting relative life consumption estimate should support the Royal Netherlands Air Force in their engine maintenance activities. The present paper describes the prediction method for the blade temperature, based on reverse engineering. Input data are the flight data of the engine performance parameters and the geometry of the HP turbine blades and vanes including film cooling orifices. The engine performance parameters are converted in HP turbine entry and exit conditions by the NLR Gas Turbine Simulation Program (GSP) engine model. Next a Computational Fluid dynamics (CFD) tool is used to calculate the resulting flow field and heat transfer coefficients without film cooling. An engineering method is used to predict the internal cooling and the resulting film injection temperature. The film cooling efficiency is estimated and a finite element method (FEM) for heat conduction completes the analysis tool. The method is illustrated by results obtained for the engine design point.

Computational Study of Turbine Blade Trailing Edge Internal Cooling

2017

Modern gas turbine efficiency is improved by active cooling of the turbine blade trailing edge. The research seeks to improve turbine efficiency by increasing the cooling performance. For some time, pin fins have been used as the most common means of heat transfer enhancement. Among different types of pin fins, circular cross-section or cylindrical pin fins are the most popular and studied pin fins. A state-of-the-art design passes cooling air through a high-solidity pin array in a cavity in the trailing edge. A novel configuration with split cylindrical pin fins in which each pin has a centered slot in the mean flow direction are considered in this study. Computational simulations of flow with the proposed design reveal a significant improvement in cooling ability as compared to the currently used solid pin arrays

Coupling of internal and external cooling of gas turbine blades

Mechanics & Industry, 2014

Showerhead cooling process which consists of internal convective cooling and external film cooling of a turbine blade is investigated using ANSYS-CFX software. The aim of the present investigation is to provide a better understanding of the fundamental nature of showerhead cooling using the three dimensional Reynolds averaged Navier Stokes analysis. A numerical model has been developed to study the effects of coupled internal and external cooling of the leading edge for a semi-elliptical body shape with the SST k-ω model. This model consists of all internal flow passages and cooling hole rows at the leading edge. The numerical results obtained are discussed and compared with experimental data available in the literature. The results show that the cooling efficiency increases with the increase of the blowing ratio and the Mach number, therefore, the overall efficiency for the steel becomes less important compared to the plexiglas which has a low thermal conductivity.