scholarly journals Particle-Vane Interaction Probability in Gas Turbine Engines

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Nicholas Bojdo ◽  
Matthew Ellis ◽  
Antonio Filippone ◽  
Merren Jones ◽  
Alison Pawley
Keyword(s):  
Reynolds Number ◽  
Guide Vane ◽  
Road Dust ◽  
Stokes Number ◽  
Spherical Particles ◽  
Accumulation Factor ◽  
Nonspherical Particles ◽  
Probability Curve ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Abstract Engine durability tests are used by manufacturers to demonstrate engine life and minimum performance when subjected to doses of test dusts, often Arizona Road Dust. Grain size distributions are chosen to replicate what enters the engine; less attention is paid to other properties such as composition and shape. We demonstrate here the differences in the probability of interaction of a particle of a given particle Reynolds number on to a vane if particle shape, vane geometry, and flow Reynolds number are varied and discuss why the traditional definition of Stokes number is inadequate for predicting the likelihood of interaction in these flows. We develop a new generalized Stokes number for nozzle guide vanes and demonstrate its use through application to 2D sections of the General Electric E3 nozzle guide vane. The new Stokes number is used to develop a reduced-order probability curve to predict the interaction efficiency of spherical and nonspherical particles, independent of flow conditions and vane geometry. We show that assuming spherical particles instead of more realistic sphericity of 0.75 can lead to as much as 25% difference in the probability of interaction at Stokes numbers of around unity. Finally, we use a hypothetical size distribution to demonstrate the application of the model to predict the total mass fraction of dust interaction with a nozzle guide vane at design point conditions and highlight the potential difference in the accumulation factor between spherical and nonspherical particles.

A Study of the Effects of Thermal Barrier Coating Surface Roughness on the Boundary Layer Characteristics of Gas Turbine Aerofoils

1988 ◽  
Vol 110 (1) ◽  
pp. 88-93 ◽  
Author(s):  
R. M. Watt ◽  
J. L. Allen ◽  
N. C. Baines ◽  
J. P. Simons ◽  
M. George
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Guide Vane ◽  
Thermal Barrier ◽  
Coating Surface ◽  
Barrier Coating ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

The effect of thermal barrier coating surface roughness on the aerodynamic performance of gas turbine aerofoils has been investigated for the case of a profile typical of current first-stage nozzle guide vane design. Cascade tests indicate a potential for significant extra loss, depending on Reynolds number, due to thermal barrier coating in its “as-sprayed” state. In this situation polishing coated vanes is shown to be largely effective in restoring their performance. The measurements also suggest a critical low Reynolds number below which the range of roughness tested has no effect on cascade efficiency. Transition detection involved a novel use of thin-film anemometers painted and fired onto the TBC surfaces.

Conjugate Heat Transfer Analysis on the Interior Surface of Nozzle Guide Vane with Combined Impingement and Film Cooling

2020 ◽  
Vol 37 (4) ◽  
pp. 327-342
Author(s):  
Arun Kumar Pujari ◽  
B. V. S. S. S Prasad ◽  
Nekkanti Sitaram
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Surface Temperature ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Guide Vane ◽  
Internal Surface ◽  
Conducting Material ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

AbstractThe effect of conjugate heat transfer is investigated on a first stage nozzle guide vane (NGV) of a high pressure gas turbine which has both impingement and film cooling holes. The study is carried out computationally by considering a linear cascade domain, having two passages formed between the vanes, with a chord length of 228 mm and spacing of 200 mm. The effect of (i) coolant and mainstream Reynolds numbers, (ii) thermal conductivity (iii) temperature difference between the mainstream and coolant at the internal surface of the nozzle guide vane are investigated under conjugate thermal condition. The results show that, with increasing coolant Reynolds number the lower conducting material shows larger percentage decrease in surface temperature as compared to the higher conducting material. However, the internal surface temperature is nearly independent of mainstream Reynolds number variation but shows significant variation for higher conducting material. Further, the temperature gradient within the solid thickness of NGV is higher for the lower conductivity material.

The Effect of Particle Size and Film Cooling on Nozzle Guide Vane Deposition

2012 ◽  
Author(s):  
C. Bonilla ◽  
J. Webb ◽  
C. Clum ◽  
B. Casaday ◽  
E. Brewer ◽  
...  
Keyword(s):  
Particle Size ◽  
Film Cooling ◽  
Guide Vane ◽  
Stokes Number ◽  
Capture Efficiency ◽  
Test Facility ◽  
Deposit Thickness ◽  
Nozzle Guide Vane ◽  
Effect Of Particle Size ◽  
Nozzle Guide

An accelerated deposition test facility is used to study the effect of particle size and film cooling on deposit roughness, spatial distribution and thickness. Tests were run at gas turbine representative inlet Mach numbers (0.08) and temperatures (1080°C). Deposits were created from a sub-bituminous coal fly ash with mass median diameters from 4 to 16 microns (Stokes numbers ranging from 0.1 to 1.9. Two CFM56-5B nozzle guide vane doublets comprising three full passages and two half passages of flow were utilized as the test articles. Tests were run with three levels of film cooling. The addition of film cooling to the vanes was shown to decrease deposit capture efficiency by as much as a factor of 3 and shift the primary location of deposit buildup to the leading edge coincident with an increased region of positive cooling backflow margin. Video taken during tests noted that film cooling holes with negative backflow margin were primary areas of deposit formation regardless of film cooling percentage. Stokes number was shown to have a marked effect on vane capture efficiency, with the largest Stokes number ash (St = 1.9) approximately 3 times as likely to stick to the vane as the smallest Stokes number ash (St = 0.1). Post test observations on deposit thickness were made using a coordinate measurement machine. Deposit thickness was noted to be reduced with decreasing Stokes number and increased film cooling percentage. Deposit surface roughness falls with particle size but is only weakly dependent on cooling level.

Numerical Investigation of Ash Deposition on Nozzle Guide Vane Endwalls

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Brian P. Casaday ◽  
Ali A. Ameri ◽  
Jeffrey P. Bons
Keyword(s):  
Guide Vane ◽  
Leading Edge ◽  
Stokes Number ◽  
Secondary Flows ◽  
Ash Deposition ◽  
Deposition Rates ◽  
Nozzle Guide Vane ◽  
Turbine Vane ◽  
Tracking Model ◽  
Nozzle Guide

A computational study was performed to determine the factors that affect ash deposition rates on the endwalls in a nozzle guide vane passage. Deposition tests were simulated in flow around a flat plate with a cylindrical leading edge, as well as through a modern, high-performance turbine vane passage. The flow solution was first obtained independent of the presence of particulates, and individual ash particles were subsequently tracked using a Lagrangian tracking model. Two turbulence models were applied, and their differences were discussed. The critical viscosity model was used to determine particle deposition. Features that contribute to endwall deposition, such as secondary flows, turbulent dispersion, or ballistic trajectories, were discussed, and deposition was quantified. Particle sizes were varied to reflect Stokes numbers ranging from 0.01 to 1.0 to determine the effect on endwall deposition. Results showed that endwall deposition rates can be as high as deposition on the leading edge for particles with a Stokes number less than 0.1, but endwall deposition rates for a Stokes number of 1.0 were less than 25% of the deposition rates on the leading edge or pressure surface of the turbine vane. Deposition rates on endwalls were largest near the leading edge stagnation region on both the cylinder and vane geometries, with significant deposition rates downstream showing a strong correlation to the secondary flows.

CFD Study of Combined Impingement and Film Cooling Flow on the Internal Surface Temperature Distribution of a Vane

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Arun Kumar Pujari
Keyword(s):  
Reynolds Number ◽  
Surface Temperature ◽  
Film Cooling ◽  
Guide Vane ◽  
Cross Flow ◽  
Internal Surface ◽  
Flow Reynolds Number ◽  
Nozzle Guide Vane ◽  
Lift Off ◽  
Nozzle Guide

Abstract Conjugate heat transfer analysis is carried out on the internal surface of the first-stage nozzle guide vane of a gas turbine, which has both impingement and film cooling holes. The mainstream flow Reynolds number and internal coolant flow Reynolds number systematically changed and its effect on internal local surface temperature variation is studied. It is found that an increase in the coolant mass flow rate causes a non-uniform decrease in the local internal surface temperature. The external film coolant jet-lift off and internal impingement cross-flow are significant contributors to the non-uniform variation in surface temperature. It is also observed that the leading edge regions are prone to jet lift-off, whereas the tip regions of the suction surface are prone to self-induced cross-flow, due to which hot patches are formed in these regions. Hot patches are observed near the hub regions of a pressure surface due to the reduced film thickness on the external surface. From these observations it is concluded that local values of internal surface temperature are differently affected in different regions of the vane surface for a given combination of mainstream and coolant flow rates. Therefore, the conventional method of obtaining the internal temperature distributions by considering generalized geometries may not yield accurate solutions, in predicting the life of the nozzle guide vane.

scholarly journals Generalised Predictions of Particle-Vane Retention Probability in Gas Turbine Engines

2021 ◽  
pp. 1-29
Author(s):  
Matthew Ellis ◽  
Nicholas Bojdo ◽  
Stephen Covey-Crump ◽  
Merren Jones ◽  
Antonio Filippone ◽  
...  
Keyword(s):  
Particle Deposition ◽  
Gas Flow ◽  
Guide Vane ◽  
Thermal Response ◽  
Stokes Number ◽  
Accumulation Factor ◽  
Airborne Particulate ◽  
Undesirable Consequence ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

Abstract The ingestion of airborne particulate into aircraft engines is an undesirable consequence of their operations, particularly in and out of arid locations which leads to reduced time between overhaul. Predicting the maintenance burden in environments rich in airborne particulate is made difficult by the large number of parameters which influence the likelihood of retention of the particles on nozzle guide vanes. In this contribution we propose a new, reduced-order model which can predict the probability of particle retention as a function of a reduced set of independent variables relating to both the carrier gas flow and particle. Two-dimensional CFD simulations of particle deposition are performed on the General Electric E3 nozzle guide vane using the existing, energy-based EBFOG particle deposition model. Results from the model are compared with experimental observations of particle deposition and show good agreement with the mass fraction retained by a vane. We introduce a function which allows the probability of retention to be calculated for a range of engine operating states and architectures by defining a new dimensionless parameter, the generalised thermal Stokes number. This parameter normalises the thermal response of a particle for all gas and particle softening temperatures allowing the retention probability function to be applied universally. Finally, we demonstrate a practical use of this model by showing its use in calculating the accumulation factor for a particle size distribution.

The Effect of Particle Size and Film Cooling on Nozzle Guide Vane Deposition

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
C. Bonilla ◽  
J. Webb ◽  
C. Clum ◽  
B. Casaday ◽  
E. Brewer ◽  
...  
Keyword(s):  
Particle Size ◽  
Film Cooling ◽  
Guide Vane ◽  
Stokes Number ◽  
Capture Efficiency ◽  
Test Facility ◽  
Deposit Thickness ◽  
Nozzle Guide Vane ◽  
Effect Of Particle Size ◽  
Nozzle Guide

An accelerated deposition test facility is used to study the effect of particle size and film cooling on deposit roughness, spatial distribution, and thickness. Tests were run at gas turbine representative inlet Mach numbers (0.08) and temperatures (1080 °C). Deposits were created from a subbituminous coal fly ash with mass median diameters from 4 to 16 micron (Stokes numbers ranging from 0.1 to 1.9). Two CFM56-5B nozzle guide vane doublets comprising three full passages and two half passages of flow were utilized as the test articles. Tests were run with three levels of film cooling. The addition of film cooling to the vanes was shown to decrease the deposit capture efficiency by as much as a factor of 3 and shift the primary location of deposit buildup to the leading edge, coincident with an increased region of positive cooling backflow margin. Video taken during the tests noted that film cooling holes with a negative backflow margin were primary areas of deposit formation, regardless of the film cooling percentage. The Stokes number was shown to have a marked effect on the vane capture efficiency, with the largest Stokes number ash (St = 1.9) approximately 3 times as likely to stick to the vane as the smallest Stokes number ash (St = 0.1). Posttest observations on the deposit thickness were made using a coordinate measurement machine. The deposit thickness was noted to be reduced with a decreasing Stokes number and an increased film cooling percentage. The deposit surface roughness falls with particle size but is only weakly dependent on the cooling level.

The Extension of a Solution-Adaptive Three-Dimensional Navier–Stokes Solver Toward Geometries of Arbitrary Complexity

1993 ◽  
Vol 115 (2) ◽  
pp. 283-295 ◽  
Author(s):  
W. N. Dawes
Keyword(s):  
Guide Vane ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Wide Range ◽  
Nozzle Guide Vane ◽  
Recent Developments ◽  
Nozzle Guide

This paper describes recent developments to a three-dimensional, unstructured mesh, solution-adaptive Navier–Stokes solver. By adopting a simple, pragmatic but systematic approach to mesh generation, the range of simulations that can be attempted is extended toward arbitrary geometries. The combined benefits of the approach result in a powerful analytical ability. Solutions for a wide range of flows are presented, including a transonic compressor rotor, a centrifugal impeller, a steam turbine nozzle guide vane with casing extraction belt, the internal coolant passage of a radial inflow turbine, and a turbine disk cavity flow.

Flow Measurements in a Nozzle Guide Vane Passage With a Low Aspect Ratio and Endwall Contouring

2000 ◽  
Author(s):  
Steven W. Burd ◽  
Terrence W. Simon
Keyword(s):  
Aspect Ratio ◽  
Flow Field ◽  
Guide Vane ◽  
Flow Measurements ◽  
Vast Number ◽  
Aspect Ratios ◽  
Nozzle Guide Vane ◽  
Endwall Contouring ◽  
Nozzle Guide

The vast number of turbine cascade studies in the literature has been performed in straight-endwall, high-aspect-ratio, linear cascades. As a result, there has been little appreciation for the role of, and added complexity imposed by, reduced aspect ratios. There also has been little documentation of endwall profiling at these reduced spans. To examine the role of these factors on cascade hydrodynamics, a large-scale nozzle guide vane simulator was constructed at the Heat Transfer Laboratory of the University of Minnesota. This cascade is comprised of three airfoils between one contoured and one flat endwall. The geometries of the airfoils and endwalls, as well as the experimental conditions in the simulator, are representative of those in commercial operation. Measurements with hot-wire anemometry were taken to characterize the flow approaching the cascade. These measurements show that the flow field in this cascade is highly elliptic and influenced by pressure gradients that are established within the cascade. Exit flow field measurements with triple-sensor anemometry and pressure measurements within the cascade indicate that the acceleration imposed by endwall contouring and airfoil turning is able to suppress the size and strength of key secondary flow features. In addition, the flow field near the contoured endwall differs significantly from that adjacent to the straight endwall.

A Method for Correlating the Influence of External Crossflow on the Discharge Coefficients of Film Cooling Holes

2000 ◽  
Vol 123 (2) ◽  
pp. 258-265 ◽  
Author(s):  
D. A. Rowbury ◽  
M. L. G. Oldfield ◽  
G. D. Lock
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Discharge Coefficient ◽  
Guide Vane ◽  
Discharge Coefficients ◽  
Nozzle Guide Vane ◽  
Aero Engine ◽  
Nozzle Guide ◽  
Film Cooling Holes ◽  
Asme Paper

An empirical means of predicting the discharge coefficients of film cooling holes in an operating engine has been developed. The method quantifies the influence of the major dimensionless parameters, namely hole geometry, pressure ratio across the hole, coolant Reynolds number, and the freestream Mach number. The method utilizes discharge coefficient data measured on both a first-stage high-pressure nozzle guide vane from a modern aero-engine and a scale (1.4 times) replica of the vane. The vane has over 300 film cooling holes, arranged in 14 rows. Data was collected for both vanes in the absence of external flow. These noncrossflow experiments were conducted in a pressurized vessel in order to cover the wide range of pressure ratios and coolant Reynolds numbers found in the engine. Regrettably, the proprietary nature of the data collected on the engine vane prevents its publication, although its input to the derived correlation is discussed. Experiments were also conducted using the replica vanes in an annular blowdown cascade which models the external flow patterns found in the engine. The coolant system used a heavy foreign gas (SF6 /Ar mixture) at ambient temperatures which allowed the coolant-to-mainstream density ratio and blowing parameters to be matched to engine values. These experiments matched the mainstream Reynolds and Mach numbers and the coolant Mach number to engine values, but the coolant Reynolds number was not engine representative (Rowbury, D. A., Oldfield, M. L. G., and Lock, G. D., 1997, “Engine-Representative Discharge Coefficients Measured in an Annular Nozzle Guide Vane Cascade,” ASME Paper No. 97-GT-99, International Gas Turbine and Aero-Engine Congress & Exhibition, Orlando, Florida, June 1997; Rowbury, D. A., Oldfield, M. L. G., Lock, G. D., and Dancer, S. N., 1998, “Scaling of Film Cooling Discharge Coefficient Measurements to Engine Conditions,” ASME Paper No. 98-GT-79, International Gas Turbine and Aero-Engine Congress & Exhibition, Stockholm, Sweden, June 1998). A correlation for discharge coefficients in the absence of external crossflow has been derived from this data and other published data. An additive loss coefficient method is subsequently applied to the cascade data in order to assess the effect of the external crossflow. The correlation is used successfully to reconstruct the experimental data. It is further validated by successfully predicting data published by other researchers. The work presented is of considerable value to gas turbine design engineers as it provides an improved means of predicting the discharge coefficients of engine film cooling holes.

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