Deposition on a Cooled Nozzle Guide Vane With Nonuniform Inlet Temperatures

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Robin Prenter ◽  
Ali Ameri ◽  
Jeffrey P. Bons
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Internal Flow ◽  
Inlet Temperature ◽  
Temperature Profiles ◽  
Deposition Rates ◽  
Nozzle Guide Vane ◽  
Tracking Model ◽  
Nozzle Guide ◽  
Hot Streak

External deposition on a slot film cooled nozzle guide vane, subjected to nonuniform inlet temperatures, was investigated experimentally and computationally. Experiments were conducted using a four-vane cascade, operating at temperatures up to 1353 K and inlet Mach number of approximately 0.1. Surveys of temperature at the inlet and exit planes were acquired to characterize the form and migration of the hot streak. Film cooling was achieved on one of the vanes using a single spanwise slot. Deposition was produced by injecting sub-bituminous ash particles with a median diameter of 6.48 μm upstream of the vane passage. Several deposition tests were conducted, including a baseline case, a hot streak-only case, and a hot streak and film cooled case. Results indicate that capture efficiency is strongly related to both the inlet temperature profiles and film cooling. Deposit distribution patterns are also affected by changes in vane surface temperatures. A computational model was developed to simulate the external and internal flow, conjugate heat transfer, and deposition. Temperature profiles measured experimentally at the inlet were applied as thermal boundary conditions to the simulation. For deposition modeling, an Eulerian–Lagrangian particle tracking model was utilized to track the ash particles through the flow. An experimentally tuned version of the critical viscosity sticking model was implemented, with predicted deposition rates matching experimental results well. Comparing overall deposition rates to results from previous studies indicates that the combined effect of nonuniform inlet temperatures and film cooling cannot be accurately simulated by simple superposition of the two independent effects; thus, inclusion of both conditions in experiments is necessary for realistic simulation of external deposition.

Deposition on a Cooled Nozzle Guide Vane With Non-Uniform Inlet Temperatures

2015 ◽  
Author(s):  
Robin Prenter ◽  
Ali Ameri ◽  
Jeffrey P. Bons
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Internal Flow ◽  
Inlet Temperature ◽  
Temperature Profiles ◽  
Deposition Rates ◽  
Nozzle Guide Vane ◽  
Tracking Model ◽  
Nozzle Guide ◽  
Hot Streak

External deposition on a slot film cooled nozzle guide vane, subjected to non-uniform inlet temperatures, was investigated experimentally and computationally. Experiments were conducted using a four-vane cascade, operating at temperatures up to 1353 K and inlet Mach number of approximately 0.1. Surveys of temperature at the inlet and exit planes were acquired to characterize the form and migration of the hot streak. Film cooling was achieved on one of the vanes using a single span-wise slot. Deposition was produced by injecting sub-bituminous ash particles with a median diameter of 6.48μm upstream of the vane passage. Several deposition tests were conducted, including a baseline case, a hot streak only case, and a hot streak and film cooled case. Results indicate that capture efficiency is strongly related to both the inlet temperature profiles and film cooling. Deposit distribution patterns are also affected by changes in vane surface temperatures. A computational model was developed to simulate the external and internal flow, conjugate heat transfer, and deposition. Temperature profiles measured experimentally at the inlet were applied as thermal boundary conditions to the simulation. For deposition modeling, an Eulerian-Lagrangian particle tracking model was utilized to track the ash particles through the flow. An experimentally tuned version of the critical viscosity sticking model was implemented, with predicted deposition rates matching experimental results well. Comparing overall deposition rates to results from previous studies indicate that the combined effect of non-uniform inlet temperatures and film cooling cannot be accurately simulated by simple superposition of the two independent effects, thus inclusion of both conditions in experiments is necessary for realistic simulation of external deposition.

The Effects of High Mainstream Turbulence and Turbine Vane Film Cooling on the Dispersion of a Simulated Hot Streak

2003 ◽  
Author(s):  
Sean Jenkins ◽  
Krishnakumar Varadarajam ◽  
David G. Bogard
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Suction Side ◽  
Peak Temperature ◽  
Nozzle Guide Vane ◽  
Turbulence Effects ◽  
High Turbulence ◽  
Nozzle Guide ◽  
Hot Streak ◽  
Film Cooling Holes

This paper presents the combined effects of high turbulence and film cooling on the dispersion of a simulated hot streak as it passes over a scaled-up nozzle guide vane. Experimental data demonstrates a considerable decay in the strength of a hot streak due to turbulence effects alone. Film cooling further reduces the peak temperature values resulting in a reduction of the peak temperature in the hot streak on the order of 75% relative to the upstream peak temperature in the hot streak. Comparisons are made between high turbulence (Tu = 20%) and moderate turbulence (Tu = 3.5%) as well as between different blowing conditions for the suction side, showerhead, and pressure side film cooling holes on a simulated nozzle guide vane.

scholarly journals An Enhanced Flow-Thermo-Structural Modeling and Validation for the Integrated Analysis of a Film Cooling Nozzle Guide Vane

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2775 ◽  
Author(s):  
Peng Guan ◽  
Yan-Ting Ai ◽  
Cheng-Wei Fei
Keyword(s):  
Thermal Stress ◽  
Film Cooling ◽  
Guide Vane ◽  
Integrated Design ◽  
Integrated Analysis ◽  
Inlet Temperature ◽  
Temperature Sensitive ◽  
Computational Accuracy ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

The target of this paper is to develop an enhanced flow-thermo-structural (FTS) model with high computational accuracy, to perform the integrated analysis of film cooling nozzle guide vane (NGV). An efficient turbulence model and weak spring approach are utilized in the enhanced FTS model. In respect of the power balance principle of aeroengine rotor shaft and temperature test of a typical combustor, the mean temperature inlet and five normalization temperature curves were confirmed, respectively. The temperature-sensitive paint (TSP) technology was used to verify the numerical simulation. From this study, we find that the predicted temperature caters for the TSP test well, between which the maximum error is less than 6%, and the maximum thermal stress is 758 MPa around the hole edges and the location of stress concentration keeps the consistency with that of the cracks. The maximum thermal stress increases by 10% with the increasing inlet temperature and reduces by about 16% with the shifting of flame peak from the outer to inner hub. The prediction provides general information on the initiation of cracks on a vane segment. The developed enhanced FTS model is validated to be workable and precise in the integrated analysis of film cooling NGV. The efforts of this study provide an integrated analysis approach of film cooling NGV and are promising to provide guidance for the integrated design of film cooling components besides NGV.

Behavior of a Coolant Film With Two Rows of Holes Along the Pressure Side of a High-Pressure Nozzle Guide Vane

1990 ◽  
Vol 112 (3) ◽  
pp. 512-520 ◽  
Author(s):  
T. Arts ◽  
A. E. Bourguignon
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Free Stream ◽  
Guide Vane ◽  
Internal Flow ◽  
Pressure Side ◽  
Free Stream Turbulence ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

The purpose of this paper is to quantify the influence on external convective heat transfer of a coolant film whose position varies along the pressure side of a high-pressure turbine nozzle guide vane. The measurements were performed in the short-duration Isentropic Light Piston Compression Tube facility of the von Karman Institute. The effects of external and internal flow are considered in terms of Mach number, Reynolds number, free-stream turbulence intensity, blowing rate, and coolant to free-stream temperature ratio. The way to evaluate these results in terms of film cooling efficiency and heat transfer coefficient is finally discussed.

Effect of Nozzle Guide Vane Lean Under Influence of Inlet Temperature Traverse

2013 ◽  
Vol 136 (7) ◽  
Author(s):  
A. Rahim ◽  
B. Khanal ◽  
L. He ◽  
E. Romero
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Tangential Displacement ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Hot Streak ◽  
The Impact

One of the most widely studied parameters in turbine blade shaping is blade lean, i.e., the tangential displacement of spanwise sections. However, there is a lack of published research that investigates the effect of blade lean under nonuniform temperature conditions (commonly referred to as a “hot-streak”) that are present at the combustor exit. Of particular interest is the impact of such an inflow temperature profile on heat transfer when the nozzle guide vane (NGV) blades are shaped. In the present work, a computational study has been carried out for a transonic turbine stage using an efficient unsteady Navier–Stokes solver (HYDRA). The configurations with a nominal vane and a compound leaned vane under uniform and hot-streak inlet conditions are analyzed. After confirming the typical NGV loading and aeroloss redistributions as seen in previous literature on blade lean, the focus has been directed to the rotor aerothermal behavior. While the overall stage efficiencies for the configurations are largely comparable, the results show strikingly different rotor heat transfer characteristics. For a uniform inlet, a leaned NGV has a detrimental effect on the rotor heat transfer. However, once the hot-streak is introduced, the trend is reversed; the leaned NGV leads to favorable heat transfer characteristics in general and for the rotor tip region in particular. The possible causal links for the observed aerothermal features are discussed. The present findings also highlight the significance of evaluating NGV shaping designs under properly conditioned inflow profiles, rather than extrapolating the wisdom derived from uniform inlet cases. The results also underline the importance of including rotor heat transfer and coolability during the NGV design process.

The Effects of High Mainstream Turbulence and Turbine Vane Film Cooling on the Dispersion of a Simulated Hot Streak

2004 ◽  
Vol 126 (1) ◽  
pp. 203-211 ◽  
Author(s):  
Sean Jenkins ◽  
Krishnakumar Varadarajan ◽  
David G. Bogard
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Suction Side ◽  
Peak Temperature ◽  
Nozzle Guide Vane ◽  
Turbulence Effects ◽  
High Turbulence ◽  
Nozzle Guide ◽  
Hot Streak ◽  
Film Cooling Holes

This paper presents the combined effects of high turbulence and film cooling on the dispersion of a simulated hot streak as it passes over a scaled-up nozzle guide vane. Experimental data demonstrates a considerable decay in the strength of a hot streak due to turbulence effects alone. Film cooling further reduces the peak temperature values resulting in a reduction of the peak temperature in the hot streak on the order of 75% relative to the upstream peak temperature in the hot streak. Comparisons are made between high turbulence Tu=20% and moderate turbulence Tu=3.5% as well as between different blowing conditions for the suction side, showerhead, and pressure side film cooling holes on a simulated nozzle guide vane.

Endwall Film Cooling Using the Staggered Combustor-Turbine Gap Leakage Flow

2014 ◽  
Author(s):  
Yang Zhang ◽  
Xin Yuan
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Inlet Temperature ◽  
Local Pressure ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Blind Area ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

A key technology of gas turbine performance improvement was the increase in the turbine inlet temperature, which brought high thermal loads to the Nozzle Guide Vane (NGV) components. Strong pressure gradients in the NGVs and the complex secondary flow field had made thermal protection more challenging. As for the endwall surface near the pressure side gill region, the relatively higher local pressure and cross flow apparently decreased the film-cooling effectiveness. The aim of this investigation was to evaluate a new design, improving the film-cooling performance in a cooling blind area with upstream staggered slot, simulating the combustor-turbine leakage gap flow. The test cascades model was manufactured according to the GE-E3 nozzle guide vane scaled model, with a scale ratio of 2.2. The experiment was performed under the inlet Mach number 0.1 and the Reynolds number 3.5×105 based on an axial chord length of 78 mm. The staggered slots were positioned upstream of the cascades to simulate the combustor-turbine gap leakage. The Pressure Sensitive Painting (PSP) technique was used to detect the film cooling effectiveness distribution on the endwall surface. Through the investigation, the following results could be achieved: 1) the film-cooling effectiveness on the endwall surface downstream the slot and along the pitchwise direction increased, with the highest parameter at Z/Pitch = 0.6; 2) a larger cooled region developed towards the suction side as the blowing ratio increased; 3) the advantage of the staggered slot was apparent on the endwall surface near the inlet area, while the coolant film was obviously weakened along the axial chord at a low blowing ratio. The influence of the staggered slots could only be detected in the downstream area of the endwall surface at the higher blowing ratio.

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.

scholarly journals Behaviour of a Two Rows of Holes Coolant Film Along the Pressure Side of a High Pressure Nozzle Guide Vane

1989 ◽  
Author(s):  
T. Arts ◽  
A. E. Bourguignon
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Guide Vane ◽  
Internal Flow ◽  
Pressure Side ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Film Cooling Efficiency ◽  
Pressure Nozzle

The purpose of this paper is to quantify the influence on external convective heat transfer of a coolant film whose position varies along the pressure side of a high pressure turbine nozzle guide vane. The measurements were performed in the short duration Isentropic Light Piston Compression Tube facility of the von Karman Institute. The effects of external and internal flow are considered in terms of Mach number, Reynolds number, freestream turbulence intensity, blowing rate and coolant to freestream temperature ratio. The way to evaluate these results in terms of film cooling efficiency and heat transfer coefficient is finally discussed.

Numerical Investigation of Ash Deposition on Nozzle Guide Vane Endwalls

2012 ◽  
Author(s):  
B. Casaday ◽  
A. Ameri ◽  
J. P. Bons
Keyword(s):  
Guide Vane ◽  
Leading Edge ◽  
Secondary Flows ◽  
Turbulent Dispersion ◽  
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 Langrangian 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 numbers 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.

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