Surface Roughness Measurements on Gas Turbine Blades

1989 ◽  
Author(s):  
Robert P. Taylor
Keyword(s):  
Surface Roughness ◽  
Laboratory Experiments ◽  
Turbine Blades ◽  
Leading Edge ◽  
Height Distribution ◽  
Turbine Engine ◽  
Gas Turbine Blades ◽  
Flow And Heat Transfer ◽  
Layer Flow ◽  
Insight Into

Results are presented from profilometer measurements of the surface roughness on inservice turbine engine blades from F-100 and TF-39 aeroengines. On each blade, one roughness profile is taken in the region of the leading edge, the mid-chord and the trailing edge on both the pressure and suction sides for a total of 6 profiles. Thirty 1st stage turbine blades are measured from each engine. Statistical computations are performed on these profiles and the root mean square height, skewness and kurtosis of the roughness height distribution are presented along with the correlation length of the autocorrelation function. The purpose of this work is to provide insight into the nature of surface roughness characteristics of inservice turbine blades which can be used in the development of scaled laboratory experiments of boundary layer flow and heat transfer on turbine engine blades.

Surface Roughness Measurements on Gas Turbine Blades

1990 ◽  
Vol 112 (2) ◽  
pp. 175-180 ◽  
Author(s):  
R. P. Taylor
Keyword(s):  
Surface Roughness ◽  
Laboratory Experiments ◽  
Turbine Blades ◽  
Leading Edge ◽  
Height Distribution ◽  
Turbine Engine ◽  
Gas Turbine Blades ◽  
Flow And Heat Transfer ◽  
Layer Flow ◽  
Insight Into

Results are presented from profilometer measurements of the surface roughness on in-service turbine engine blades from F-100 and TF-39 aeroengines. On each blade, one roughness profile is taken in the region of the leading edge, the midchord and the trailing edge on both the pressure and suction sides for a total of six profiles. Thirty first-stage turbine blades are measured from each engine. Statistical computations are performed on these profiles and the root mean square height, skewness and kurtosis of the roughness height distribution are presented along with the correlation length of the autocorrelation function. The purpose of this work is to provide insight into the nature of surface roughness characteristics of in-service turbine blades which can be used in the development of scaled laboratory experiments of boundary layer flow and heat transfer on turbine engine blades.

scholarly journals Study of surface quality using quasi-optimal correlation algorithms

2018 ◽  
Vol 224 ◽  
pp. 01077
Author(s):  
Nicolay V. Nosov
Keyword(s):  
Surface Roughness ◽  
Turbine Blades ◽  
Variable Component ◽  
Electronic Unit ◽  
Average Amplitude ◽  
New Approach ◽  
Turbine Engine ◽  
Computer Methods ◽  
Engine Blade ◽  
Electronic Method

The article proposes a new approach for evaluating roughness of the profile surface of gas turbine engine blade airfoils after vibratory polishing. An optical electronic unit was used to study microgeometry of blade suction and pressure sides: video imagery of the surface was processed using computer methods to obtain the average amplitude of the autocorrelation function variable component. The applied optical electronic method of evaluating microgeometry of compressor/turbine blades allows obtaining fields of surface roughness and tension concentration coefficients as well as analyzing the finish machining technology to a greater depth.

Calculation of Optimal Surface Roughness With Respect to Lift/Drag Forces Acting on Wind Turbine Blade

2014 ◽  
Author(s):  
Xuerui Mao ◽  
Simon Hogg
Keyword(s):  
Surface Roughness ◽  
Boundary Conditions ◽  
Smooth Surface ◽  
Adjoint Equation ◽  
Turbine Blades ◽  
Leading Edge ◽  
Sensitivity Study ◽  
Small Magnitude ◽  
Viscous Forces ◽  
Drag Forces

Roughness on the surface of turbine blades induced by icing, dirt, erosion or manufacturing imperfections changes the aerodynamic configurations of wind turbines and reduces the power generation efficiency. In this work, a modified NACA0024 aerofoil is adopted to study effects of surface roughness on lift/drag forces. Three Reynolds numbers, 1000, 2000 and 5000 and a range of angles of attack [0°,20°] are studied. Since the magnitude of the roughness is small, it can be modelled as non-zero velocity boundary conditions imposed on the smooth surface without roughness. The flow with surface roughness can be therefore decomposed as the sum of a flow without roughness and a flow induced by roughness (or the velocity boundary conditions). The first flow can be obtained by solving the Navier-Stokes (NS) equation while the second one is governed by the linearized NS equation. Correspondingly the lift and drag forces acting on the aerofoil can be also decomposed as the sum of a force without considering roughness and a force induced by roughness. Instead of studying a particular type or distribution of roughness, we calculate the optimal roughness, which changes aerodynamic forces most effectively. This optimal roughness is obtained through a sensitivity study by solving an adjoint equation of the linearized NS equation. It is found that the optimal roughness with respect to both drag and lift forces is concentrated around the trailing edge and upper leading edge of the aerofoil and the lift is much more sensitive to roughness than the drag. Then the optimal roughness with a small magnitude is added to the smooth aerofoil geometry and this new geometry is tested through direct numerical simulations (DNS). It is found that the optimal roughness with a small magnitude (e-norm, defined as the square integration of the roughness around the surface, 0.001) induces over 10% change of the lift. Comparing the forces acting on the smooth surface and on the rough surface, it is noticed that the roughness changes the pressure force significantly while has little influence on the viscous forces. The pressure distribution is further inspected to study mechanisms of the effects of roughness on forces.

scholarly journals Surface Roughness Prediction and Minimization in 5-Axis Milling Operations of Gas Turbine Blades

2021 ◽  
Author(s):  
Arameh Eyvazian ◽  
Farayi Musharavati ◽  
Afrasyab Khan ◽  
Mohsen Soori ◽  
Tamer A. Sebaey ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Machining Process ◽  
Machining Parameters ◽  
Gas Turbine Blades ◽  
Virtual Machining ◽  
Machined Parts ◽  
Machining System

Abstract To enhance the quality of machined parts, virtual machining systems are presented in this study. In the turbine blades, the minimization of the surface roughness of the blades can decrease the Reynolds number to decrease the loss of energy in power generation. Due to difficulties of polishing process in minimizing the surface roughness of machined blades, the optimized machining parameters for minimizing the surface roughness is an effective solution for the problem. In this study, a virtual machining system is developed to predict and minimize the surface roughness in 5-Axis machining operations of gas turbine blades. To minimize the surface roughness, the machining parameters were optimized by the Genetic algorithm. To validate the developed system, the turbine blades were machined using a 5-Axis CNC machine tool and the machined blades were measured using the CMM machine to obtain the surface roughness of machined parts. So, a 41.29% reduction in the measured surface roughness and a 42.09% reduction in the predicted surface roughness are obtained using the optimized machining parameters. The developed virtual machining system can be applied in the machining process of turbine blades to enhance the surface quality of machined blades and thus improve the efficiency of gas turbines.

High-Pressure Gas Turbine Vane Turbulent Flows and Heat Transfer Predicted by RANS/LES/DES

2017 ◽  
Author(s):  
Ping Dong ◽  
R. S. Amano
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Gas Turbine ◽  
Turbulent Flows ◽  
Film Cooling ◽  
Turbine Blades ◽  
Suction Side ◽  
Gas Turbine Blades ◽  
Flow And Heat Transfer ◽  
Turbine Vane

The lifetime of the modern gas turbines greatly depends on the durability of hot section components operating at high temperatures. Film cooling is key to air cooling technologies in modern gas turbine and widely used in high-temperature and high-pressure blades as an active cooling scheme. The requirements of accurate prediction of aerodynamic flow and heat transfer in gas turbine blades lay the essential foundation of cooling effectiveness improvement and working life estimation. In recent days, Large Eddy Simulations (LES) is considered as a useful tool to predict turbulent flows and heat transfer around gas turbine blades, but, comparing to the Reynolds-Averaged Navier–Stokes (RANS) methods, the LES method usually needs more computing resource and depends on computational power and mesh quality. In this paper, LES/DES (Detached Eddy Simulation) predictions were compared to RANS prediction with interest in the accuracy and improvement of turbulent flow and heat transfer phenomena around NASA’s C3X high-pressure gas turbine vane with leading edge cooling film. RANS/LES/DES were detailed and further investigated to assess their ability to predict flow and heat transfer in boundary layer around C3X vane. The current predictions showed that the mix between film cooling injections and free stream resulted in complex flow and heat transfer in the boundary layer on the external vane surface. The predictions of the aerodynamic load along the C3X vane with RANS/LES/DES were almost identical and agreed well with the experimental results. However, the heat transfer predictions with RANS/LES/DES were different. The transition prediction showed the best agreement with the experiment data in the most region. The LES prediction only partially agreed with the experimental data before separation point on the suction side and mild pressure gradient region on the pressure side. The DES and RANS predictions agreed with the experiment data after separation point on the suction side and most region on the pressure side.

Foreign object damage on the leading edge of gas turbine blades

2014 ◽  
Vol 33 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Seyed Masoud Marandi ◽  
Kh. Rahmani ◽  
Mehdi Tajdari
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Leading Edge ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Gas Turbine Blades

Research on the Effects of Dimples and Protrusions on Flow and Heat Transfer in Matrix Cooling Channels in Turbine Blades

2019 ◽  
Author(s):  
Yigang Luan ◽  
Lianfeng Yang ◽  
Yue Yin ◽  
Pietro Zunino
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Heat Transfer Performance ◽  
Turbine Blades ◽  
Inlet Temperature ◽  
Transfer Performance ◽  
Turbine Inlet Temperature ◽  
Turbine Engine ◽  
Cooling Channels ◽  
Flow And Heat Transfer

Abstract Nowadays, gas turbine engines play an indispensable role in modern industry, which have been widely used especially in the aviation, marine and energy fields. The turbine inlet temperature is one of the most important factors that influences the performance of the turbine engine. It’s acknowledged that the higher turbine inlet temperature contributes to the overall gas turbine engine efficiency. Therefore, the internal cooling technology of turbine blades is of vital importance. This paper mainly studies the effects of dimples and protrusions on flow and heat transfer in matrix cooling channels and optimize the performance of the matrix cooling structure by numerical simulation and experiment methods. Thirteen cases have been calculated under Re = 10,000∼80,000 by the commercial code ANSYS Fluent. Structures with different layouts of dimples and protrusions were considered, such as the number, distance and the depth ratio. The original model has been strengthened due to the dimple and protrusion structure, which improves heat transfer performance as well as the thermal performance factor (TPF) on condition that the pressure loss increases slightly. Meanwhile, the optimized structures have been made and tested by the transient liquid crystal technique (TLC). A comparison between the CFD results and the experimental data is made. Note that the heat transfer performance is much better when the ratio of the dimple depth and the dimple diameter is equal to 0.3, compared with the ratio of 0.1 and 0.2. In terms of the cases with two sides dimples, the heat transfer can be enhanced by increasing the number of the dimples. In addition, the heat transfer performance is the best when both of dimples and protrusions are applied. Nu/Nu0 and TPF increase by up to approximately 7% and 5% respectively.

Sign in / Sign up

Export Citation Format

Share Document