A numerical study of high pressure turbine forced response in the presence of damaged nozzle guide vanes

2007 ◽  
Vol 111 (1125) ◽  
pp. 751-757 ◽  
Author(s):  
L.di Mare ◽  
M. Imregun ◽  
A. D. Smith ◽  
R. Elliott
Keyword(s):  
High Pressure ◽  
Numerical Study ◽  
Guide Vane ◽  
Flow Simulation ◽  
Forced Response ◽  
High Pressure Turbine ◽  
Simulation Code ◽  
Engine Order ◽  
Viscous Compressible Flow ◽  
Nozzle Guide

Abstract This paper reports results from numerical computations of low engine order and blade-passing forced response on the rotor of a high pressure turbine due to severe damage to a single nozzle guide vane. The computations are performed using a time-domain, nonlinear viscous compressible flow simulation code. The flow and the levels of forcing for a few selected modes are compared for the undamaged and the damaged configurations. The results show that the response in various modes is affected to a different extent by the damage. The main blade-passing response was found to be largely unaffected, if not marginally reduced. On the other hand, the vibration levels for some modes were seen to be up to eight times higher because of the low-order excitation harmonics created by the damaged passage.

Forced Response Experiments in a High Pressure Turbine Stage

2002 ◽  
Author(s):  
Holger Hennings ◽  
Robert Elliott
Keyword(s):  
High Pressure ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Forced Response ◽  
Flexible Rotor ◽  
High Pressure Turbine ◽  
Validation Data ◽  
Pressure Transducers ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

An experimental investigation was conducted on a single stage high pressure turbine in order to gain a deeper unterstanding of turbine blade forced response. In particular the main objective of this experiment was to obtain good quality validation data for the prediction methods used by major engine manufacturers. The stage investigated consists of an uncooled nozzle guide vane (NGV) and a rotor with 64 blades. To study the complete forced response problem a so called Flexible Rotor was designed and manufactured. This rotor has three modes of interest in the operating range of the stage: first torsion, second flap and second edge. The design of the experiment was supported by detailed CFD and structural analysis. The mechanical behavior of the Flexible Rotor is well known. In order to identify all interesting modes all blades are equipped with strain gauges individually calibrated. To check the unsteady pressures 18 unsteady pressure transducers were mounted at midspan. This paper deals with experiments only with the Flexible Rotor. Forced response results are presented for the first torsion mode at two different pressure ratios. The results obtained show a large scatter for the maximum response amplitudes at each pressure ratio. The distribution of the amplitudes around the disk is controlled by the mechanical properties of the rotor.

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.

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.

Vibration Analysis of a Mistuned Axial Turbine Blisk

2019 ◽  
Author(s):  
Bernd Beirow ◽  
Arnold Kühhorn ◽  
Felix Figaschewsky ◽  
Alfons Bornhorn
Keyword(s):  
Guide Vane ◽  
Forced Response ◽  
Impact Testing ◽  
Algorithm Optimization ◽  
Axial Turbine ◽  
Testing Procedures ◽  
Influence Coefficients ◽  
Engine Order ◽  
Turbine Blisk ◽  
Nozzle Guide

Abstract An axial turbine blisk for turbocharger applications is analyzed with respect to the effect of intentional mistuning on the forced response. Originally, the intentional mistuning pattern has been designed by employing a genetic algorithm optimization in order to reduce the forced response caused by low engine order excitation (LEO) of the fundamental flap mode. The solution found has been implemented in a prototype of that blisk. For the purpose of comparison, a second reference blisk has been manufactured without intentional mistuning. The actual mistuning distributions of the blisks have been identified by employing blade-by-blade impact testing. Alternatively, a new inverse approach has been employed, which is based on a least squares formulation and benefits from less experimental effort. Based on the information gained by the aforementioned testing procedures, subset of nominal systems (SNM)-models have been updated, which allow for considering the aeroelastic coupling by means of aerodynamic influence coefficients (AIC). Despite of small but unavoidable deviations from the design intention it could be proved within numerical simulations that the intended 70 per cent reduction of the maximum forced response is nevertheless achieved. In addition, the paper is addressing the effect of the aforementioned intentional mistuning pattern on a higher mode, which is relevant for the durability as well. Hence, new SNM-models have to be updated in order to calculate the forced response due to EO-excitation caused by the nozzle guide vane. Although the original mistuning pattern has been optimized solely for reducing the forced response of the fundamental flap mode, it hardly affects the higher mode forced response in a negative manner.

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.

scholarly journals Aero-thermal redesign of a high pressure turbine nozzle guide vane

2019 ◽  
Vol 8 (4) ◽  
pp. 310-319
Author(s):  
Hadi Yavari ◽  
Ali Khavari ◽  
Mohammad Alizadeh ◽  
Behrad Kashfi ◽  
Hiwa Khaledi
Keyword(s):  
High Pressure ◽  
Guide Vane ◽  
High Pressure Turbine ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

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.

scholarly journals Coupled Heat Transfer Simulation of a High-pressure Turbine Nozzle Guide Vane

2009 ◽  
Vol 22 (3) ◽  
pp. 230-236 ◽  
Author(s):  
Wang Qiang ◽  
Guo Zhaoyuan ◽  
Zhou Chi ◽  
Feng Guotai ◽  
Wang Zhongqi
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Guide Vane ◽  
High Pressure Turbine ◽  
Coupled Heat Transfer ◽  
Nozzle Guide Vane ◽  
Heat Transfer Simulation ◽  
Nozzle Guide
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