Coating Effect on Particle Trajectories and Turbine Blade Erosion

1992 ◽  
Vol 114 (2) ◽  
pp. 250-257 ◽  
Author(s):  
W. Tabakoff ◽  
M. Metwally

Gas turbine engines operating in dusty environments are exposed to erosion and performance deterioration. In order to improve the erosion resistance, nickel and cobalt superalloy blades and vanes are widely used in the hot section of gas turbines. Protective coatings have been used to enhance superalloy resistance to hot erosion. An investigation has been conducted to study coal ash particle dynamics and resulting blade erosion for both uncoated and coated blades of a two-stage axial flow gas turbine. A quasi-three-dimensional flow solution is obtained for each blade row for accurate computation of particle trajectories. The change in particle momentum due to collision with the turbine blades and casings is modeled using restitution parameters derived from three-component laser-Doppler velocimeter measurements. The erosion models for both blade superalloy and coatings are derived based on the erosion data obtained by testing the blade superalloy and coatings in a high-temperature erosion wind tunnel. The results show both the three-dimensional particle trajectories and the resulting blade impact locations for both uncoated and coated blade surfaces. In addition are shown the distribution of the erosion rate, impact frequency, impact velocity, and impact angle for the superalloy and the coating. The results indicate significant effects of the coating, especially on blade erosion and material deterioration.

Author(s):  
Sven Gunnar Sundkvist ◽  
Michael Andersson ◽  
Bogdan Gherman ◽  
Andreas Sveningsson ◽  
Damian Vogt

This paper describes a way of co-operation between industries, universities and government that has proven to be very fruitful. The Swedish Gas Turbine Centre (GTC) is constituted as a research consortium between technical universities and gas turbine industry. The overall goal of the centre, that was founded in 1996 on a governmental initiative, is to build up a basis of knowledge at Swedish universities to support the industrial development in Sweden of gas turbines of the future with expected requirements on low emissions, high efficiencies, high availability, and low costs. Since the start the research has had a focus on high temperature components of gas turbines (combustion chamber and turbine). This is also reflected in the on-going development phase where the research program consists of four project areas: cooling technology, combustion technology, aeroelasticity, and life time prediction of hot components. The projects are aiming at developing design tools and calculation and verification methods within these fields. A total of eleven research students (among them one industrial PhD student) are active in the centre at present. Numerical analysis as well as experimental verification in test rigs are included. The program has so far produced eleven Licentiate of Engineering and five PhD. On-going activities and recent results of the research in the four research areas are presented: • A new test rig for investigation of time-dependent pressures of three-dimensional features on a vibrating turbine blade at realistic Mach, Reynolds and Strouhal numbers and first experimental results. • Results of numerical simulations of heat loads on turbine blades and vanes, especially platform cooling. • First results of numerical investigations of combustion and thermo-acoustic instabilities in gas turbine chambers. • Experimental investigation of crack propagation in gas turbine materials using the scanning electron microscope (SEM).


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7843
Author(s):  
Mariusz Bogdan ◽  
Józef Błachnio ◽  
Artur Kułaszka ◽  
Dariusz Zasada

This article presents issues concerning the relationship between the degradation of the coating of gas turbine blades and changes in the color of its surface. Conclusions were preceded by the determination of parameters characterizing changes in the technical condition of protective coatings made based on a metallographic examination that defined the morphological modifications of the microstructure of the coating, chemical composition of oxides, and roughness parameters. It has been shown that an increased operating time causes parameters that characterize the condition of the blades to deteriorate significantly. Results of material tests were compared with those of blade surface color analyses performed using a videoscope. Image data were represented in two color models, i.e., RGB and L*a*b* with significant differences being observed between parameters in both representations. The study results demonstrated a relationship between the coating degradation degree and changes in the color of the blade’s surface. Among others, this approach may be used as a tool to assess the condition of turbine blades as well as entire gas turbines.


1989 ◽  
Vol 111 (3) ◽  
pp. 310-314 ◽  
Author(s):  
A. Hamed

This work presents the results of an investigation conducted to study the effect of secondary flow on blade erosion by coal ash particles in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three-dimensional trajectory analysis within the turbine blade passages. The blade material erosion behavior and the particle rebound characteristics are simulated using empirical equations derived from experimental measurements. The results demonstrate that the secondary flow has a significant influence on the blade erosion intensity and pattern for the typical ash particle size distribution considered in this investigation.


Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
M. Metwally

This work presents the results of an investigation conducted to study the effect of coal ash particles size distribution on the particle dynamics, and the resulting blade erosion in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three dimensional trajectory analysis within the turbine blade passages. The particle rebound conditions and the blade material erosion characteristics are simulated using empirical equations, derived from experimental measurements. For the typical ash particle size distribution considered in this investigation, the results demonstrate that the size distribution has a significant influence on the blade erosion intensity and pattern.


Author(s):  
Takao Mikami ◽  
Shinya Tanaka ◽  
Masashi Tatsuzawa ◽  
Takeshi Sakida

The CGT301 ceramic gas turbine is being developed under a contract from NEDO as a part of the New Sunshine Program of MTTI to improve the performance of gas turbines for cogeneration through the replacement of hot section components with ceramic parts. The project is conducted in three phases. The project currently in Phase 2 focuses on the development of the “primary type” ceramic gas turbine (turbine inlet temperature: 1,200°C). CGT301 is a recuperated, single-shaft, ceramic gas turbine. The turbine is a two-stage axial flow type. The major effort has been on the development of the turbine which consists of metallic disks and inserted ceramic blades (“hybrid rotor”). Prior to engine tests, component tests were performed on the hybrid rotor to prove the validity of the design concepts and their mechanical integrity. The engine equipped with all ceramic components except the second stage turbine blades was tested and evaluated. The engine was operated successfully for a total of 23 hours without failure at the rated engine speed of 56,000 rpm with the turbine inlet temperature of 1,200 °C. Further, the engine equipped with all ceramic components was successfully tested for one hour under the same conditions. Engine testing of the “primary type” ceramic gas turbine is continuing to improve the performance and the reliability of the system for the purpose of moving forward to the development of the “pilot” ceramic gas turbine (turbine inlet temperature: 1,350 °C) as the final target of this project. This paper summarizes the progress in the development of the CGT301 with the emphasis on the test results of the hybrid rotor.


1956 ◽  
Vol 60 (549) ◽  
pp. 563-589 ◽  
Author(s):  
D. G. Ainley

The 985th Lecture to be given before the Society, “ The High Temperature Turbo-jet Engine ” by D. G. Ainley, B.Sc, A.M.I.Mech.E., A.F.R.Ae.S., was given at the Institution of Civil Engineers, Great George St., London, S.W.I on 15th March 1956, with Mr. N. E. Rowe, C.B.E., D.I.C., F.C.G.I., F.I.A.S., F.R.Ae.S., in the Chair. Introducing the Lecturer, Mr. Rowe said that Mr. Ainley had been working on gas turbines since 1943 when he joined the gas turbine division of the Royal Aircraft Establishment. He transferred to Power Jets Ltd. and later to the National Gas Turbine Establishment. His early work was associated with the development of axial flow compressors, contraction design and so on; he then transferred to turbine design, became head of the section dealing with turbine and heat transfer problems and for the past five or six years had been chiefly engaged on the cooling of gas turbine blades. Mr. Ainley graduated from the University of London, Queen Mary College, with first class honours. In 1953 he was awarded the George Stephenson Research Prize by the Institution of Mechanical Engineers.


1991 ◽  
Vol 113 (4) ◽  
pp. 607-615 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
M. Metwally

This work presents the results of an investigation conducted to study the effect of coal ash particle size distribution on the particle dynamics, and the resulting blade erosion in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three-dimensional trajectory analysis within the turbine blade passages. The particle rebound conditions and the blade material erosion characteristics are simulated using empirical equations, derived from experimental measurements. For the typical ash particle size distribution considered in this investigation, the results demonstrate that the size distribution has a significant influence on the blade erosion intensity and pattern.


2020 ◽  
Author(s):  
Ky-Quang Pham ◽  
Quang-Hai Nguyen ◽  
Tai-Duy Vu ◽  
Cong-Truong Dinh

Abstract Gas turbine engine has been widely applied to many heavy industries, such as marine propulsion and aerospace fields. Increasing turbine inlet temperature is one of the major ways to improve the thermal efficiency of gas turbines. Internal cooling for gas turbine cooling system is one of the most commonly used approaches to reduce the temperature of blades by casting various kinds of ribs in serpentine passages to enhance the heat transfer between the coolant and hot surface of gas turbine blades. This paper presents an investigation of boot-shaped rib design to increase the heat transfer performances in the internal cooling turbine blades for gas turbine engines. By varying the design parameter configuration, the airflow is taken with higher momentum, and the minor vortex being at the front rib is relatively removed. The object of this investigation is increasing the reattachment airflow to wall and reducing the vortex occurring near the rib for improving the performances of heat transfer using three-dimensional Reynolds-averaged Navier-Stokes with the SST model. A parametric study of the boot-shaped rib design was performed using various geometric parameters related to the heel-angle, toe-angle, slope-height and rib-width to find their effect on the Nusselt number, temperature on the ribbed wall, friction factor ratio of the channel and thermal performance factor. The numerical results showed that the heat transfer performances are significantly increased with the heel-angle, toe-angle, slope-height, while that remained relatively constant with the rib-width.


1986 ◽  
Vol 18 (5) ◽  
pp. 610-615 ◽  
Author(s):  
A. P. Voloshchenko ◽  
G. N. Tret'yachenko ◽  
L. B. Getsov ◽  
B. M. Zinchenko ◽  
I. S. Malashenko ◽  
...  

Author(s):  
Farrokh Zarifi-Rad ◽  
Hamid Vajihollahi ◽  
James O’Brien

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.


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