Nozzle Passage Endwall Effectiveness Values With Various Combustor Coolant Flowrates—Part 2: Endwall and Vicinity Surface Effectiveness Measurements

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Kedar P. Nawathe ◽  
Rui Zhu ◽  
Enci Lin ◽  
Yong W. Kim ◽  
Terrence W. Simon
Keyword(s):  
Gas Turbines ◽  
Guide Vane ◽  
Suction Surface ◽  
Turbine Engine ◽  
Pressure Surface ◽  
Coolant Injection ◽  
Measurement Results ◽  
Nozzle Guide Vane ◽  
Effectiveness Measurement ◽  
Nozzle Guide

Abstract Effective coolant schemes are required for providing cooling to the first-stage stator vanes of gas turbines. To correctly predict coolant performance on the endwall and vane surfaces, these coolant schemes should also consider the effects of coolant streams introduced upstream in the combustor section of a gas turbine engine. This two-part paper presents measurements taken on a first-stage nozzle guide vane cascade that includes combustor coolant injection. The first part of this paper explains how coolant transport and coolant-mainstream interaction in the vane passage is affected by changing the combustor coolant and endwall film coolant flowrates. This paper explains how those flows affect the coolant effectiveness on the endwall and vane surfaces. Part one showed that a significant amount of coolant injected upstream of the endwall is present along the pressure surface of the vanes as well as over the endwall. Part two shows effectiveness measurement results taken in this study on the endwall and pressure and suction surfaces of the vanes. Sustained endwall coolant effectiveness is observed along the whole passage for all cases. It is uniform in the pitch-wise direction. Combustor coolant flow significantly affects cooling performance even near the trailing edge. The modified flowfield results in the pressure surface being cooled more effectively than the suction surface. While the effectiveness distribution on the pressure surface varies with combustor and film coolant flowrates, the distribution along the suction surface remains largely unchanged.

Nozzle Passage Endwall Effectiveness Values With Various Combustor Coolant Flow Rates: Part 2 — Endwall and Vicinity Surface Effectiveness Measurements

2020 ◽  
Author(s):  
Kedar P. Nawathe ◽  
Rui Zhu ◽  
Enci Lin ◽  
Yong W. Kim ◽  
Terrence W. Simon
Keyword(s):  
Gas Turbines ◽  
Guide Vane ◽  
Coolant Flow ◽  
Suction Surface ◽  
Flow Rates ◽  
Turbine Engine ◽  
Pressure Surface ◽  
Measurement Results ◽  
Effectiveness Measurement ◽  
Nozzle Guide

Abstract Effective coolant schemes are required for providing cooling to the first stage stator vanes of gas turbines. To correctly predict coolant performance on the endwall and vane surfaces, these coolant schemes should also consider the effects of coolant streams introduced upstream in the combustor section of a gas turbine engine. This two-part paper presents measurements taken on a first-stage nozzle guide vane cascade that includes combustor coolant injection. The first part of this paper explains how coolant transport and coolant-mainstream interaction in the vane passage is affected by changing the combustor coolant and endwall film coolant flow rates. This paper explains how those flows affect the coolant effectiveness on the endwall. Part one showed that a significant amount of coolant injected upstream of the endwall is present along the pressure surface of the vanes as well as over the endwall. Part two shows effectiveness measurement results taken in this study on the endwall and pressure and suction surfaces of the vanes. Sustained endwall coolant effectiveness is observed along the whole passage for all cases. It is uniform in the pitch-wise direction. Combustor coolant flow significantly affects cooling performance even near the trailing edge. The modified flow field results in the pressure surface being cooled more effectively than the suction surface. While the effectiveness distribution on the pressure surface varies with combustor and film coolant flow rates, the suction surface remains largely unchanged.

scholarly journals Secondary Flow Reduction in a Nozzle Guide Vane Cascade by Non-Axisymmetric End-Wall Profiling

1999 ◽  
Author(s):  
J. Yan ◽  
D. G. Gregory-Smith ◽  
P. J. Walker
Keyword(s):  
Secondary Flow ◽  
Static Pressure ◽  
Guide Vane ◽  
Suction Surface ◽  
Linear Cascade ◽  
Pressure Surface ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
End Wall

A linear cascade of HP steam turbine nozzle guide vanes was designed and built in order to study the effect of a non-axisymmetric profile for the endwall. The profile was designed by using CFD for the purpose of reducing the secondary flow. The method was to use convex curvature near the pressure surface to reduce the static pressure and concave curvature near the suction surface to increase it. Thus the cross passage pressure gradient which drives the secondary flow would be reduced. Detailed investigations of the flow field with a flat end-wall and the profiled end-wall were conducted. The effect of the profiled end-wall on the secondary flow development was determined and also compared with the CFD design predictions. It was found that the secondary loss and secondary kinetic energy were both reduced by about 20% with the shaped endwall, and a more uniform exit flow was also achieved.

Failure Analysis of Nozzle Guide Vane of a Low Pressure Turbine in an Aero Gas Turbine Engine

2014 ◽  
Vol 14 (5) ◽  
pp. 578-587 ◽  
Author(s):  
R. K. Mishra ◽  
Johney Thomas ◽  
K. Srinivasan ◽  
Vaishakhi Nandi ◽  
Raghavendra Bhat
Keyword(s):  
Failure Analysis ◽  
Gas Turbine ◽  
Guide Vane ◽  
Low Pressure ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Low Pressure Turbine ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

scholarly journals Gas Turbine Testing on Naval Distillate Fuel

1971 ◽  
Author(s):  
J. S. Siemietkowski
Keyword(s):  
Gas Turbine ◽  
Diesel Fuel ◽  
Guide Vane ◽  
Engine Operation ◽  
Accelerated Corrosion ◽  
Turbine Engine ◽  
Base Materials ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Distillate Fuel

A Pratt & Whitney FT4A Marine Gas Turbine Engine rated at 22,600 hp, 3600 rpm was run at the Naval Ship Engineering Center, Philadelphia Division for 1000 hr. Fuel used was naval distillate having a vanadium level of 0.5 ppm. Basically there was no problem with engine operation on naval distillate when compared to diesel fuel. The smoke level was barely visible at high powers. Coalescent fuel filters are a problem due to their relatively short (100–130 hr) life. The corrosion rate was accelerated when compared to navy diesel fuel. The fuel parameter suspect is vanadium, however other parameters may be at fault. Additional efforts are required into definitely determining the cause of accelerated corrosion and also into optimizing nozzle guide vane and turbine blade base materials and coatings.

Effects of Endwall Film Coolant Flowrate on Secondary Flows and Coolant Mixing in a First Stage Nozzle Guide Vane

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Mahmood H. Alqefl ◽  
Kedar P. Nawathe ◽  
Pingting Chen ◽  
Rui Zhu ◽  
Yong W. Kim ◽  
...  
Keyword(s):  
Test Section ◽  
Film Cooling ◽  
Gas Turbines ◽  
Thermal Loading ◽  
Guide Vane ◽  
Secondary Flows ◽  
Cooling Flows ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Endwall Film Cooling

Abstract Modern gas turbines are subjected to very high thermal loading. This leads to a need for aggressive cooling to protect components from damage. Endwalls are particularly challenging to cool due to a complex system of secondary flows near them that wash and disrupt the protective coolant films. This highly three-dimensional flow not only affects but is also affected by the momentum of film cooling flows, whether injected just upstream of the passage to intentionally cool the endwall or as combustor cooling flows injected further upstream in the engine. This complex interaction between the different cooling flows and passage aerodynamics has been recently studied in a first stage nozzle guide vane. The present paper presents a detailed study on the sensitivity of aero-thermal interactions to endwall film cooling mass flow to mainstream flow ratio. The test section represents a first stage nozzle guide vane with a contoured endwall and endwall film cooling injected just upstream of it. The test section also includes an engine-representative combustor–turbine interface geometry with combustor cooling flows injected at a constant rate. The approach flow conditions represent flow exiting a low-NOx combustor. Adiabatic surface thermal measurements and in-passage velocity and thermal field measurements are presented and discussed. The results show the dynamics of passage vortex suppression and the increase of impingement vortex strength as MFR changes. The effects of these changes of secondary flows on coolant distribution are presented.

A new experimental approach for heat transfer coefficient and adiabatic wall temperature measurements on a Nozzle Guide Vane with inlet temperature distortions

2021 ◽  
pp. 1-33
Author(s):  
Tommaso Bacci ◽  
Alessio Picchi ◽  
Bruno Facchini ◽  
Simone Cubeda
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Wall Temperature ◽  
Gas Turbines ◽  
Experimental Approach ◽  
Guide Vane ◽  
Adiabatic Wall ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Abstract Modern gas turbines lean combustors are used to limit NOx pollutant emissions; on the other hand, their adoption presents other challenges, especially concerning the combustor-turbine interaction. Turbine inlet conditions are generally characterized by severe temperature distortions and swirl degree, which is responsible for very high turbulence intensities. Past studies have focused on the description of the effects of these phenomena on the behavior of the high pressure turbine. Nevertheless, very limited experimental results are available when it comes to evaluate the heat transfer coefficient (HTC) on the nozzle guide vane surface, since relevant temperature distortions present a severe challenge for the commonly adopted measurement techniques. The work presented in this paper was carried out on a non-reactive, annular, three-sector rig, made by a combustor simulator and a NGV cascade. It can reproduce a swirling flow, with temperature distortions at the combustor-turbine interface plane. This test apparatus was exploited to develop an experimental approach to retrieve heat transfer coefficient and adiabatic wall temperature distributions simultaneously, to overcome the known limitations imposed by temperature gradients on state-of-the-art methods for HTC calculation from transient tests. A non-cooled mockup of a NGV doublet, manufactured using low thermal diffusivity plastic material, was used for the tests, carried out using IR thermography with a transient approach. In the authors' knowledge, this presents the first experimental attempt of measuring a nozzle guide vane heat transfer coefficient in the presence of relevant temperature distortions and swirl.

scholarly journals The Effects of Combustor Cooling Features on Nozzle Guide Vane Film Cooling Experiments

2018 ◽  
Author(s):  
Nicholas E. Holgate ◽  
Peter T. Ireland ◽  
Eduardo Romero
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Stagnation Region ◽  
Airfoil Surface ◽  
Cooling Performance ◽  
Nozzle Guide Vane ◽  
Effectiveness Measurement ◽  
Extraneous Radiation ◽  
Nozzle Guide ◽  
Endwall Film Cooling

Recent advances in experimental methods have allowed researchers to study nozzle guide vane film cooling in the presence of combustor dilution ports and endwall films. The dilution injection creates nonuniformities in temperature, velocity, and turbulence, and an understanding of the vane film cooling performance is complicated by competing influences. In this study, dilution port temperature profiles have been measured in the absence of vane film cooling and compared to film effectiveness measurements in the presence of both films and dilution, illustrating the effects of the dilution port turbulence on film cooling performance. It is found that dilution port injection can create significant effectiveness benefits at the difficult-to-cool vane stagnation region, due to the more turbulent hot mainstream enhancing the mixing of film coolant jets that have left the airfoil surface. Also explored are the implications of endwall film cooling for infrared vane surface temperature measurements. The reduced endwall temperatures reduce the thermal emissions from this surface, so reducing the amount of extraneous radiation reflected from the vane surface where measurements are being made. The results of a detailed calibration show that the maximum local film effectiveness measurement error could be up to 0.05 if this effect were to go unaccounted for.

Nozzle Guide Vane Assembly for Air-Cooled Retrofit Turbine Case Kit

2013 ◽  
Author(s):  
Venkata Rambabu Dabiru ◽  
Devidasa Pai Gorte ◽  
Simone Colantoni
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Guide Vane ◽  
Water Cooling ◽  
Actuation System ◽  
Nozzle Guide Vane ◽  
Turbine Casing ◽  
Nozzle Guide ◽  
Water Cooling System

Variable Guide Vanes are common to many of the Gas Turbines. Nozzle Guide Vane (NGV) is a variable nozzle present in the hot gas path of a twin-shaft gas turbine. In addition to guiding the hot gases onto the buckets, the NGV also controls the energy split between the high-pressure turbine and power turbine. The NGV is rotated to the desired position for different machine operability requirements through an actuation system. A twin shaft gas turbine equipped with NGV allows higher operational flexibility and higher efficiency at partial load/speed. MS3002F is a heavy duty gas turbine developed by GE in 1960’s with water cooling system for the turbine casing and the NGV. Over the period of time, technology has evolved and water cooling system in Gas Turbines has become obsolete, as it leads to uneven cooling of the casing and scaling that cause performance losses, unplanned outages and down-time. To cater the existing fleet with improved reliability and availability, a new product introduction program was launched to design air-cooled system to replace the water-cooled system, within the boundaries of retrofit ability. The air cooling is achieved by extracted secondary flow air; the reduction on performance due to this is compensated by increasing the firing temperature. Owing to the removal of water cooling and increased firing temperature, the turbine casing and hot gas path components including NGV have to be redesigned. The present paper discusses the redesign of the NGV assembly for new air-cooled configuration. This redesign includes geometry modification, assembly interface definition (contact geometry and coating), and material selection. The key challenge is to redesign the NGV with no cooling (neither water nor extracted secondary flow) while maintaining the steady state clearances of the NGV assembly as those of water-cooled kit. These redesigned components are validated for structural integrity under loads affecting fatigue, creep and oxidation. The verification of the functional integrity of NGV actuation system (that was originally designed for water-cooled system) for all operating conditions relevant to the new air-cooled turbine case kit is also discussed.

Impact of the Combustor-Turbine Interface Slot Orientation on the Durability of a Nozzle Guide Vane Endwall

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Alan Thrift ◽  
Karen Thole ◽  
Satoshi Hada
Keyword(s):  
Guide Vane ◽  
Leading Edge ◽  
Time Resolved ◽  
Turbine Engine ◽  
External Cooling ◽  
Image Velocimetry ◽  
Nozzle Guide Vane ◽  
Edge Vortex ◽  
Nozzle Guide ◽  
Stagnation Plane

The combustor-turbine interface is an essential component in a gas turbine engine as it allows for thermal expansion between the first stage turbine vanes and combustor section. Although not considered as part of the external cooling scheme, leakage flow from the combustor-turbine interface can be utilized as coolant. This paper reports on the effects of orientation of a two-dimensional leakage slot, simulating the combustor-turbine interface, on the net heat flux reduction to a nozzle guide vane endwall. In addition to adiabatic effectiveness and heat transfer measurements, time-resolved, digital particle image velocimetry (TRDPIV) measurements were performed in the vane stagnation plane. Four interface slot orientations of 90 deg, 65 deg, 45 deg, and 30 deg located at 17% axial chord upstream of a first vane in a linear cascade were studied. Results indicate that reducing the slot angle to 45 deg can provide as much as a 137% reduction to the average heat load experienced by the endwall. Velocity measurements indicate the formation of a large leading edge vortex for coolant injected at 90 deg and 65 deg while coolant injected at 45 deg and 30 deg flows along the endwall and washes up the vane surface at the endwall junction.

Life enhancement of Nozzle Guide Vane of an Aero Gas Turbine Engine through Pack Aluminization

2017 ◽  
Vol 0 (0) ◽  
Author(s):  
R K Mishra ◽  
Prashant Kumar ◽  
K Rajesh ◽  
C R Das ◽  
Ganapathi Sharma ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Aluminide Coating ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Nozzle Guide Vane ◽  
Life Enhancement ◽  
Nozzle Guide ◽  
Metallurgical Evaluation ◽  
Operating Cycles

AbstractPack aluminization of high pressure turbine nozzle guide vane of an aero gas turbine engine has been carried out following a well defined systematic procedure. The process parameters are first optimized on dummy vanes and optimized process is followed for the actual vanes for evaluation and testing. Visual and binocular examination followed by metallurgical evaluation have been carried out to validate the process and to establish the adequacy and correctness of the coating. The coated vanes are then evaluated through engine level tests for performance and durability. The results of engine level tests and inspection post accelerated mission test cycles ensure that the vanes with aluminide coating can withstand severe engine operating cycles without any damage or failure which would otherwise would have happened without the coating. The condition of vanes post endurance test is also an indication of enhanced life of the vanes with coating.

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