Design of a High Pressure Turbine Nozzle Guide Vane with Effective Film Cooling System on Leading Edge

2016 ◽  
Author(s):  
Firat Kiyici ◽  
Tekin Aksu ◽  
Sitki Uslu
Keyword(s):  
High Pressure ◽  
Film Cooling ◽  
Cooling System ◽  
Guide Vane ◽  
Leading Edge ◽  
High Pressure Turbine ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Multi-Fidelity Modelling of a Fully-Featured HP Turbine Stage

2017 ◽  
Author(s):  
Giorgio Occhioni ◽  
Shahrokh Shahpar ◽  
Haidong Li
Keyword(s):  
High Pressure ◽  
Film Cooling ◽  
State Of The Art ◽  
Guide Vane ◽  
Phase Lag ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Film Cooling Holes

An improvement in overall efficiency and power output for gas turbine engines can be obtained by increasing the combustor exit temperature, but the thermal management of metal parts exposed to hot gases is challenging. Discrete film cooling, combined with internal convective cooling is the current state-of-the-art available to aerothermal designers of these components. To simplify the simulation problem in the aerodynamic design phase, it is common practice to replace the cooling holes with source strips applied to the blade. This could lead to inaccuracies in high pressure turbine performance prediction. This study has been carried out on a fully-featured high pressure turbine stage using high-fidelity simulations. The film cooling holes on the nozzle guide vane and on the rotor are initially modelled using a strip model approach. Then, to increase the model fidelity, the strips on the suction side of the rotor are replaced with discrete fan shaped film cooling holes. A rigid body rotation is also applied to the nozzle guide vane to vary the stage capacity and reaction. The effects of the mesh topology & resolution are also taken into account. The results obtained with these two approaches are then compared, giving the designers a better understanding on film cooling modelling and relationship between capacity, reaction and performance. The accurate prediction of the complex interaction between cavity inflows and the main-flow, still represent a challenge for the state of the art RANS solvers. Hence, an unsteady phase-lag approach has been used to overcome the RANS limitations. A validation of the unsteady solutions has been carried out with respect to experimental data.

Comprehensive Geometric Description of Manufacturing Scatter of High-Pressure Turbine Nozzle Guide Vanes for Probabilistic CFD Analysis

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Paul Voigt ◽  
Lars Högner ◽  
Barbara Fiedler ◽  
Matthias Voigt ◽  
Ronald Mailach ◽  
...  
Keyword(s):  
High Pressure ◽  
Film Cooling ◽  
Guide Vane ◽  
Input Parameter ◽  
Three Dimensional ◽  
Leading Edge ◽  
Scanning System ◽  
High Pressure Turbine ◽  
Pressure Loss Coefficient ◽  
Nozzle Guide

The increasing demands on jet engines require progressive thermodynamic process parameters, which typically lead to higher aerothermal loadings and accordingly to designs with high complexity. State-of-the-art high-pressure turbine (HPT) nozzle guide vane (NGV) design involves vane profiles with three-dimensional features including a high amount of film cooling and profiled endwalls (PEWs). Typically, the specific mass flow, also called capacity, which governs the engine's operation, is set by the HPT NGV. Hence, geometric variations due to manufacturing scatter of the HPT NGV's passage can affect relevant aerodynamic quantities and the entire engine behavior. Within the traditional deterministic design approach, the influences of those geometric variations are covered by conservative assumptions and engineering experience. This paper addresses the consideration of variability due to the manufacturing of HPT NGVs through probabilistic CFD investigations. To establish a statistical database, 80 HPT NGVs are digitized with a high precision optical 3D scanning system to record the outer geometry. The vane profiles are parametrized by a section-based approach. For this purpose, traditional profile theory is combined with a novel method that enables the description of NGV profile variability taking the particular leading edge (LE) shape into account. Furthermore, the geometric variability of PEWs is incorporated by means of principle component analysis (PCA). On this basis, a probabilistic system assessment including a sensitivity analysis in terms of capacity and total pressure loss coefficient is realized. Sampling-based methods are applied to conduct a variety of 3D CFD simulations for a typical population of profile and endwall geometries. This probabilistic investigation using realistic input parameter distributions and correlations contributes to a robust NGV design in terms of relevant aerodynamic quantities.

COMPARISON OF FILM COOLING PERFORMANCE FOR DIFFERENT PURGE SLOT CONFIGURATIONS IN A CYLINDRICAL AND STATE-OF-THE-ART NOZZLE GUIDE VANE

2021 ◽  
pp. 1-13
Author(s):  
Christian Landfester ◽  
Gunther Mueller ◽  
Robert Krewinkel ◽  
Clemens Domnick ◽  
Martin Böhle
Keyword(s):  
High Pressure ◽  
Film Cooling ◽  
State Of The Art ◽  
Guide Vane ◽  
High Pressure Turbine ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Abstract This comparative study is concerned with the advances in nozzle guide vane (NGV) design developments and their influence on endwall film cooling performance by injecting coolant through the purge slot. This experimental study compares the film cooling effectiveness and the aerodynamic effects for different purge slot configurations on both a flat and an axisymmetrically contoured endwall of a NGV. While the flat endwall cascade was equipped with cylindrical vanes, the contoured endwall cascade consisted of modern NGVs which represent state-of-the-art high-pressure turbine design standards. Geometric variations, e.g. the slot width and injection angle, as well as different blowing ratios were realized. The mainstream flow parameters were set to meet real engine conditions with regard to Reynolds and Mach numbers. Pressure Sensitive Paint was used to determine the adiabatic film cooling effectiveness. Five-hole probe measurements were performed to measure the flow field in the vane wake region. For a more profound insight into the origin of the secondary flows, oil dye visualizations were carried out. The results show that the advances in NGV design have a significantly positive influence on the distribution of the coolant. This has to be attributed to lesser disturbance of the coolant propagation by secondary flow for the optimized NGV design, since the design features are intended to suppress the formation of secondary flow. It is therefore advisable to take these effects into account when designing the film cooling system of a modern high-pressure turbine.

Comprehensive Geometric Description of Manufacturing Scatter of High Pressure Turbine Nozzle Guide Vanes for Probabilistic CFD Analysis

2018 ◽  
Author(s):  
Paul Voigt ◽  
Lars Högner ◽  
Barbara Fiedler ◽  
Matthias Voigt ◽  
Ronald Mailach ◽  
...  
Keyword(s):  
High Pressure ◽  
Film Cooling ◽  
Guide Vane ◽  
Input Parameter ◽  
Three Dimensional ◽  
Leading Edge ◽  
Scanning System ◽  
High Pressure Turbine ◽  
Pressure Loss Coefficient ◽  
Nozzle Guide

The increasing demands on jet engines require progressive thermodynamic process parameters, which typically lead to higher aerothermal loadings and accordingly to designs with high complexity. State of the art high pressure turbine (HPT) nozzle guide vane (NGV) design involves vane profiles with three-dimensional features including a high amount of film cooling and profiled endwalls (PEW). Typically, the specific massflow, also called capacity, which governs the engine’s operation, is set by the HPT NGV. Hence, geometric variations due to manufacturing scatter of the HPT NGV’s passage can affect relevant aerodynamic quantities and the entire engine behavior. Within the traditional deterministic design approach, the influences of those geometric variations are covered by conservative assumptions and engineering experience. This paper addresses the consideration of variability due to manufacturing of HPT NGVs through probabilistic CFD investigations. In order to establish a statistical database, 80 HPT NGVs are digitized with a high precision optical 3D scanning system to record the outer geometry. The vane profiles are parametrized by a section based approach. For this purpose, traditional profile theory is combined with a novel method that enables the description of NGV profile variability taking the particular leading edge (LE) shape into account. Furthermore, the geometric variability of PEWs is incorporated by means of principle component analysis (PCA). On this basis, a probabilistic system assessment including a sensitivity analysis in terms of capacity and total pressure loss coefficient is realized. Sampling-based methods are applied in order to conduct a variety of 3D CFD simulations for a typical population of profile and endwall geometries. This probabilistic investigation using realistic input parameter distributions and correlations contributes to a robust NGV design in terms of relevant aerodynamic quantities.

Numerical Prediction of Cooling Performance Sensitivity of 1st Stage Nozzle Guide Vane Under Aerothermal Conditions

2019 ◽  
Author(s):  
Prasert Prapamonthon ◽  
Bo Yin ◽  
Guowei Yang ◽  
Mohan Zhang
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
High Pressure ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
High Pressure Turbine ◽  
Cooling Performance ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Abstract To obtain high power and thermal efficiency, the 1st stage nozzle guide vanes of a high-pressure turbine need to operate under serious circumstances from burned gas coming out of combustors. This leads to vane suffering from effects of high thermal load, high pressure and turbulence, including flow-separated transition. Therefore, it is necessary to improve vane cooling performance under complex flow and heat transfer phenomena caused by the integration of these effects. In fact, these effects on a high-pressure turbine vane are controlled by several factors such as turbine inlet temperature, pressure ratio, turbulence intensity and length scale, vane curvature and surface roughness. Furthermore, if the vane is cooled by film cooling, hole configuration and blowing ratio are important factors too. These factors can change the aerothermal conditions of the vane operation. The present work aims to numerically predict sensitivity of cooling performances of the 1st stage nozzle guide vane under aerodynamic and thermal variations caused by three parameters i.e. pressure ratio, coolant inlet temperature and height of vane surface roughness using Computational Fluid Dynamics (CFD) with Conjugate Heat Transfer (CHT) approach. Numerical results show that the coolant inlet temperature and the vane surface roughness parameters have significant effects on the vane temperature, thereby affecting the vane cooling performances significantly and sensitively.

Comparison of Film Cooling Performance for Different Purge Slot Configurations in a Cylindrical and State-of-the-Art Nozzle Guide Vane

2021 ◽  
Author(s):  
Christian Landfester ◽  
Gunther Müller ◽  
Robert Krewinkel ◽  
Clemens Domnick ◽  
Martin Böhle
Keyword(s):  
Secondary Flow ◽  
Film Cooling ◽  
State Of The Art ◽  
Guide Vane ◽  
High Pressure Turbine ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Abstract This comparative study is concerned with the advances in nozzle guide vane (NGV) design developments and their influence on the film cooling performance by injecting coolant through the purge slot. An experimental study compares the film cooling effectiveness as well as the aerodynamic effects for different purge slot configurations on both a flat and an axisymmetrically contoured endwall of a NGV. While the flat endwall cascade was equipped with four cylindrical vanes, the contoured endwall cascade consisted of four modern NGVs which represent state-of-the-art high-pressure turbine design standards. Geometric variations, e.g. the purge slot width and injection angle, as well as different blowing ratios (BR) at an engine-like density ratio (DR = 1.6) were realized to investigate the real-life effect of thermal expansion, design modifications and the interaction between secondary flow and coolant. The mainstream flow parameters were set to meet real engine conditions with regard to Reynolds and Mach numbers. The Pressure Sensitive Paint (PSP) technique was used to determine the adiabatic film cooling effectiveness. Five-hole probe measurements (DR = 1.0) were performed to measure the flow field with its characteristic vortex structures as well as the loss distribution in the vane wake region. For a more profound insight into the origin and development of the secondary flows, oil dye visualizations were carried out on both endwalls. The measurement results will be discussed based on a side-by-side comparison of the distribution of film cooling effectiveness on the endwall, its area-averaged values as well as the two-dimensional distribution of total pressure losses and the secondary flow field. The results of this study show that the advances in NGV design development have had a significantly positive influence on the distribution of the coolant. This has to be attributed to lesser disturbance of the coolant propagation by secondary flow for the optimized NGV design, since the design features are intended to suppress the formation of secondary flow. In contrast to the results of the cylindrical profile, sufficient cooling can be already provided with a perpendicular injection in the case of the modern NGV. It is therefore advisable to take these effects into account when designing the film cooling system of a modern high-pressure turbine.

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.

Aero-Thermal Aspects of Film Cooled Nozzle Guide Vane Endwalls: Part 1 — Aerodynamics

2020 ◽  
Author(s):  
Mahmood H. Alqefl ◽  
Kedar P. Nawathe ◽  
Pingting Chen ◽  
Rui Zhu ◽  
Yong W. Kim ◽  
...  
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Three Dimensional ◽  
Leading Edge ◽  
Secondary Flows ◽  
Protective Film ◽  
Cooling Flows ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Endwall Film Cooling

Abstract The first stage turbine of a modern gas turbine is subjected to high thermal loads which lead to a need for aggressive cooling schemes to protect its components from melting. Endwalls are particularly challenging to cool due to the complex system of secondary flows near them that wash the protective film coolants into the mainstream. This paper shows that without including combustor cooling, the complex secondary flow physics are not representative of modern engines. Aggressive injection of all cooling flows upstream of the passage is expected to interact and change passage aerodynamics and, subsequently, mixing and transport of coolants. This study describes, experimentally, the aero-thermal interaction of cooling flows near the endwall of a first stage nozzle guide vane passage. The test section involves an engine-representative combustor-turbine interface geometry, combustor coolant flow and endwall film cooling flow injected upstream of a linear cascade. The approach flow conditions represent flow exiting a cooled, low-NOx combustor. This first part of this two-part study aims to understand the complex aerodynamics near the endwall through detailed measurements of passage three-dimensional velocity fields with and without endwall film cooling. The aerodynamic measurements reveal a dominant vortex in the passage, named here as the Impingement Vortex, that opposes the passage vortex formed at the airfoil leading edge plane. This Impingement Vortex completely changes our description of flow over a modern film cooled endwall.

Aero-thermal Aspects of Film Cooled Nozzle Guide Vane Endwall - Part 1: Aerodynamics

2021 ◽  
pp. 1-54
Author(s):  
Mahmood H. Alqefl ◽  
Kedar P. Nawathe ◽  
Pingting Chen ◽  
Rui Zhu ◽  
Yong W. Kim ◽  
...  
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Three Dimensional ◽  
Leading Edge ◽  
Secondary Flows ◽  
Protective Film ◽  
Cooling Flows ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Endwall Film Cooling

Abstract The first stage turbine of a modern gas turbine is subjected to high thermal loads which lead to a need for aggressive cooling schemes to protect its components from melting. Endwalls are particularly challenging to cool due to the complex system of secondary flows near them that wash the protective film coolants into the mainstream. This paper shows that without including combustor cooling, the complex secondary flow physics are not representative of modern engines. Aggressive injection of all cooling flows upstream of the passage is expected to interact and change passage aerodynamics and, subsequently, mixing and transport of coolants. This study describes, experimentally, the aero-thermal interaction of cooling flows near the endwall of a first stage nozzle guide vane passage. The test section involves an engine-representative combustor-turbine interface geometry, combustor coolant flow and endwall film cooling flow injected upstream of a linear cascade. The approach flow conditions represent flow exiting a cooled, low-NOx combustor. This first part of this two-part study aims to understand the complex aerodynamics near the endwall through detailed measurements of passage three-dimensional velocity fields with and without endwall film cooling. The aerodynamic measurements reveal a dominant vortex in the passage, named here as the Impingement Vortex, that opposes the passage vortex formed at the airfoil leading edge plane. This Impingement Vortex completely changes our description of flow over a modern film cooled endwall.

Experimental Evaluation of Cooling Effectiveness of High Pressure Turbine Nozzle Guide Vane

2012 ◽  
Author(s):  
S. Venkatasubramanya ◽  
S. A. Vasudev ◽  
Sunil Chandel
Keyword(s):  
High Pressure ◽  
Air Temperature ◽  
Guide Vane ◽  
Internal Cooling ◽  
Temperature Ratio ◽  
High Pressure Turbine ◽  
Cooling Effectiveness ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Cooling Air

High pressure turbine nozzle guide vane of a gas turbine engine, which operates at gas temperatures in excess of 1700 K, employs internal cooling, augmented convective cooling, impingement cooling and film cooling techniques to keep the vane in safe operating limits. Even though nozzle guide vanes are designed using heat transfer co-relations available in published papers and fundamental data, it is required to test the nozzle guide vane to ascertain the surface metal temperature and verify the adequacy of cooling. Adequacy of cooling is quantified by the term cooling effectiveness expressed and as percentage. The objective of the current work is to study the effect of gas to cooling air temperature ratio on cooling effectiveness. In the current study tests were first conducted to validate the test cascade in accordance with AGARD recommendations. Later tests were conducted to verify the constancy of cooling effectiveness across two gas temperatures and finally effect of gas to cooling air temperature ratio on cooling effectiveness was studied. The ratio was increased by a factor of 0.69 in leading edge and 0.72 in the trailing edge circuit and found that the cooling effectiveness remained constant.

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