Aerothermal Performance of Shielded Vane Design

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Ioanna Aslanidou ◽  
Budimir Rosic
Keyword(s):  
Heat Transfer ◽  
Total Pressure ◽  
High Speed ◽  
Guide Vane ◽  
Leading Edge ◽  
Experimental Facility ◽  
Numerical Studies ◽  
Nozzle Guide Vane ◽  
Inlet Conditions ◽  
Nozzle Guide

This paper presents an experimental investigation of the concept of using the combustor transition duct wall to shield the nozzle guide vane leading edge. The new vane is tested in a high-speed experimental facility, demonstrating the improved aerodynamic and thermal performance of the shielded vane. The new design is shown to have a lower average total pressure loss than the original vane, and the heat transfer on the vane surface is overall reduced. The peak heat transfer on the vane leading edge–endwall junction is moved further upstream, to a region that can be effectively cooled as shown in previously published numerical studies. Experimental results under engine-representative inlet conditions showed that the better performance of the shielded vane is maintained under a variety of inlet conditions.

Effect of the Combustor Wall on the Aerothermal Field of a Nozzle Guide Vane

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Ioanna Aslanidou ◽  
Budimir Rosic
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Guide Vane ◽  
Leading Edge ◽  
Flow Structures ◽  
Experimental Facility ◽  
Aerodynamic Loss ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Processing Techniques

In gas turbines with can combustors, the trailing edge (TE) of the combustor transition duct wall is found upstream of every second vane. This paper presents an experimental and numerical investigation of the effect of the combustor wall TE on the aerothermal performance of the nozzle guide vane. In the measurements carried out in a high-speed experimental facility, the wake of this wall is shown to increase the aerodynamic loss of the vane. On the other hand, the wall alters secondary flow structures and has a protective effect on the heat transfer in the leading edge-endwall junction, a critical region for component life. The different clocking positions of the vane relative to the combustor wall are tested experimentally and are shown to alter the aerothermal field. The experimental methods and processing techniques adopted in this work are used to highlight the differences between the different cases studied.

Heat Transfer Studies on the Interior Surfaces of Cooled Nozzle Guide Vane in a Linear Cascade

2015 ◽  
Author(s):  
Arun Kumar Pujari ◽  
Bhamidi Prasad ◽  
Nekkanti Sitaram
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Guide Vane ◽  
Internal Heat ◽  
Leading Edge ◽  
Internal Surface ◽  
Transfer Coefficients ◽  
Computational Data ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Experimental and computational heat transfer investigations are reported in the interior side of a nozzle guide vane (NGV) subjected to combined impingement and film cooling. The domain of study is a two dimensional five-vane cascade having four passages. Each vane has a chord length of 228 mm and the pitch distance between the vanes is 200 mm. The vane internal surface is cooled by dry air supplied through the two impingement inserts: the front and the aft. The mass flow through the impingement chamber is varied, for a fixed spacing (H) to jet diameter (d) ratio of 1.2. The surface temperature distributions, at certain locations of the vane interior, are measured by pasting strips of liquid crystal sheets. The vane interior surface temperature distribution is also obtained by computations carried out by using Shear stress transport (SST) k-ω turbulence model in the ANSY FLUENT-14 flow solver. The computational data are in good agreement with the measured values of temperature. The internal heat transfer coefficients are thence determined along the leading edge and the mid span region from the computational data.

Effects of an Axisymmetric Contoured Endwall on a Nozzle Guide Vane: Convective Heat Transfer Measurements

2010 ◽  
Author(s):  
A. A. Thrift ◽  
K. A. Thole ◽  
S. Hada
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Leading Edge ◽  
Critical Factor ◽  
Suction Side ◽  
Leakage Flow ◽  
Cross Sectional ◽  
Nozzle Guide Vane ◽  
Linear Slope ◽  
Nozzle Guide

Heat transfer is a critical factor in the durability of gas turbine components, particularly in the first vane. An axisymmetric contour is sometimes used to contract the cross sectional area from the combustor to the first stage vane in the turbine. Such contouring can lead to significant changes in the endwall flows thereby altering the heat transfer. This paper investigates the effect of axisymmetric contouring on endwall heat transfer of a nozzle guide vane. Heat transfer measurements are performed on the endwalls of a planar and contoured passage whereby one endwall is modified with a linear slope in the case of the contoured passage. Included in this study is upstream leakage flow issuing from a slot normal to the inlet axis. Each of the endwalls within the contoured passage presents a unique flowfield. For the contoured passage, the flat endwall is subject to an increased acceleration through the area contraction while the contoured endwall includes both increased acceleration and a turning of streamlines due to the slope. Results indicate heat transfer is reduced on both endwalls of the contoured passage relative to the planar passage. In the case of all endwalls, increasing leakage mass flow rate leads to an increase in heat transfer near the suction side of the vane leading edge.

Effect of Simulated Combustor Temperature Nonuniformity on HP Vane and Endwall Heat Transfer: An Experimental and Computational Investigation

2010 ◽  
Author(s):  
Imran Qureshi ◽  
Arrigo Beretta ◽  
Thomas Povey
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Research Programme ◽  
Test Facility ◽  
Inlet Temperature ◽  
Computational Investigation ◽  
Nozzle Guide Vane ◽  
Inlet Conditions ◽  
Nozzle Guide ◽  
Computational Predictions

This paper presents experimental measurements and computational predictions of surface and endwall heat transfer for a high-pressure (HP) nozzle guide vane (NGV) operating as part of a full HP turbine stage in an annular rotating turbine facility, with and without inlet temperature distortion (hot-streaks). A detailed aerodynamic survey of the vane surface is also presented. The test turbine was the unshrouded MT1 turbine, installed in the Turbine Test Facility (previously called Isentropic Light Piston Facility) at QinetiQ, Farnborough UK. This is a short duration facility, which simulates engine representative M, Re, non-dimensional speed and gas-to-wall temperature ratio at the turbine inlet. The facility has recently been upgraded to incorporate an advanced second-generation combustor simulator, capable of simulating well-defined, aggressive temperature profiles in both the radial and circumferential directions. This work forms part of the pan-European research programme, TATEF II. Measurements of HP vane and endwall heat transfer obtained with inlet temperature distortion are compared with results for uniform inlet conditions. Steady and unsteady CFD predictions have also been conducted on vane and endwall surfaces, using the Rolls-Royce CFD code HYDRA to complement the analysis of experimental results. The heat transfer measurements presented in this paper are the first of their kind in the respect that the temperature distortion is representative of an extreme cycle point measured in the engine situation, and was simulated with good periodicity and with well defined boundary conditions in the test turbine.

Effects of an Axisymmetric Contoured Endwall on a Nozzle Guide Vane: Convective Heat Transfer Measurements

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
A. A. Thrift ◽  
K. A. Thole ◽  
S. Hada
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Leading Edge ◽  
Critical Factor ◽  
Suction Side ◽  
Leakage Flow ◽  
Cross Sectional ◽  
Nozzle Guide Vane ◽  
Linear Slope ◽  
Nozzle Guide

Heat transfer is a critical factor in the durability of gas turbine components, particularly in the first vane. An axisymmetric contour is sometimes used to contract the cross sectional area from the combustor to the first stage vane in the turbine. Such contouring can lead to significant changes in the endwall flows, thereby altering the heat transfer. This paper investigates the effect of axisymmetric contouring on the endwall heat transfer of a nozzle guide vane. Heat transfer measurements are performed on the endwalls of a planar and contoured passage whereby one endwall is modified with a linear slope in the case of the contoured passage. Included in this study is upstream leakage flow issuing from a slot normal to the inlet axis. Each of the endwalls within the contoured passage presents a unique flow field. For the contoured passage, the flat endwall is subject to an increased acceleration through the area contraction, while the contoured endwall includes both increased acceleration and a turning of streamlines due to the slope. Results indicate heat transfer is reduced on both endwalls of the contoured passage relative to the planar passage. In the case of all endwalls, increasing leakage mass flow rate leads to an increase in heat transfer near the suction side of the vane leading edge.

An Internal Heat Transfer Study in a Cooled Nozzle Guide Vane of a Linear Cascade

2014 ◽  
Author(s):  
Arun Kumar Pujari ◽  
Prasad B. V. S. S. Subrahmanyaa ◽  
Sitaram Nekkanti
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Film Cooling ◽  
Guide Vane ◽  
Internal Heat ◽  
Leading Edge ◽  
Internal Surface ◽  
Structure Variation ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Experimental and computational heat transfer investigations are reported in the interior mid span of the pressure surface of a Nozzle Guide Vane (NGV) subjected to combined impingement and film cooling. The study is carried out by considering a two dimensional cascade domain having four passages formed between the five vane each has a chord length of 228 mm and spacing (between the blades) of 200 mm. The vane internal surface is cooled by two impingement inserts namely front and aft impingement tubes. The front impingement tube is used to cool the internal side of the leading edge of the NGV whereas the aft impingement tube is used to cool mainly the mid span of the internal surface. The mass flow through the impingement chamber is varied for a fixed target plate distance to jet diameter ratio of 1.12. The surface temperature at the mid chord region was measured by liquid crystal technique. The surface temperature obtained from both experiments and computations are compared and the computationally obtained average heat transfer coefficient distribution along chord reported. The flow structure variation along the chord and its effect on Nusselt number distribution is presented. The computation is carried out by using Shear stress transport (SST) k-ω turbulence model in the ANSY FLUENT-14 flow solver.

scholarly journals Numerical Study on the Effect of Thermocouple Mounting Coating on Temperature Measurement of Nozzle Guide Vane

2020 ◽  
Vol 38 (1) ◽  
pp. 95-103
Author(s):  
Peng Guan ◽  
Yanting Ai ◽  
Yi Xu ◽  
Ming Zhao ◽  
Jing Tian
Keyword(s):  
Heat Transfer ◽  
Temperature Measurement ◽  
Coating Thickness ◽  
Measurement Accuracy ◽  
Guide Vane ◽  
Leading Edge ◽  
Suction Side ◽  
Middle Surface ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

To analyze the measurement error of thermocouple covered by mounting coating, which is mainly used in air-engine nozzle guide vane temperature test, a mathematical model of the temperature measurement structure was established referring to Mark Ⅱ nozzle guide vane. Based on the heat-flow coupling theory and conjugate heat transfer analysis, the Navier-Stokes equations and heat transfer problem were solved by using SST γ-θ turbulence model. The effects of coating position, coating thickness and coating edge fillet on the temperature of test positions were investigated, respectively. From this study, we find that the temperature predicted by SST γ-θ turbulence model well caters for the test data. The maximum error between calculation and test result is less than 10%. When the leading edge coating is near to the transition point of the suction side, the temperature error will increase. Comparing with that on the middle surface of the pressure side and the leading surface of the suction side, the thermocouple coating has slight effect on the temperature measurement accuracy of the middle surface and the trailing surface of the suction side. If the coating thickness is less than the total temperature boundary layer thickness, the measurement accuracy is almost unaffected. To apply a fillet to the leading edge of thermocouple coating is an effective method to improve the measurement accuracy.

Influence of Leading Edge Fillet and Nonaxisymmetric Contoured Endwall on Turbine NGV Exit Flow Structure and Interactions With the Rim Seal Flow

2013 ◽  
Author(s):  
Özhan H. Turgut ◽  
Cengiz Camcı
Keyword(s):  
Flow Structure ◽  
Total Pressure ◽  
Guide Vane ◽  
Axial Flow ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Constant Thickness ◽  
Computational Evaluation ◽  
Nozzle Guide

Three different ways are employed in the present paper to reduce the secondary flow related total pressure loss. These are nonaxisymmetric endwall contouring, leading edge (LE) fillet, and the combination of these two approaches. Experimental investigation and computational simulations are applied for the performance assessments. The experiments are carried out in the Axial Flow Turbine Research Facility (AFTRF) having a diameter of 91.66cm. The NGV exit flow structure was examined under the influence of a 29 bladed high pressure turbine rotor assembly operating at 1300 rpm. For the experimental measurement comparison, a reference Flat Insert endwall is installed in the nozzle guide vane (NGV) passage. It has a constant thickness with a cylindrical surface and is manufactured by a stereolithography (SLA) method. Four different LE fillets are designed, and they are attached to both cylindrical Flat Insert and the contoured endwall. Total pressure measurements are taken at rotor inlet plane with Kiel probe. The probe traversing is completed with one vane pitch and from 8% to 38% span. For one of the designs, area averaged loss is reduced by 15.06%. The simulation estimated this reduction as 7.11%. Computational evaluation is performed with the rotating domain and the rim seal flow between the NGV and the rotor blades. The most effective design reduced the mass averaged loss by 1.28% over the whole passage at the NGV exit.

Influence of Pre-History and Leading Edge Contouring on Aero-Performance of a 3D Nozzle Guide Vane

2013 ◽  
Author(s):  
Ranjan Saha ◽  
Boris I. Mamaev ◽  
Jens Fridh ◽  
Björn Laumert ◽  
Torsten H. Fransson
Keyword(s):  
Guide Vane ◽  
Three Dimensional ◽  
Leading Edge ◽  
Stagnation Line ◽  
Wide Range ◽  
Nozzle Guide Vane ◽  
Turbine Vane ◽  
Loss Coefficients ◽  
Exit Mach Number ◽  
Nozzle Guide

Experiments are conducted to investigate the effect of the pre-history in the aerodynamic performance of a three-dimensional nozzle guide vane with a hub leading edge contouring. The performance is determined with two pneumatic probes (5 hole and 3 hole) concentrating mainly on the endwall. The investigated vane is a geometrically similar gas turbine vane for the first stage with a reference exit Mach number of 0.9. Results are compared for the baseline and filleted cases for a wide range of operating exit Mach numbers from 0.5 to 0.9. The presented data includes loading distributions, loss distributions, fields of exit flow angles, velocity vector and vorticity contour, as well as, mass-averaged loss coefficients. The results show an insignificant influence of the leading edge fillet on the performance of the vane. However, the pre-history (inlet condition) affects significantly in the secondary loss. Additionally, an oil visualization technique yields information about the streamlines on the solid vane surface which allows identifying the locations of secondary flow vortices, stagnation line and saddle point.

Experimental Study of the Endwall Heat Transfer of a Transonic Nozzle Guide Vane With Upstream Jet Purge Cooling: Part 1 — Effect of Density Ratio

2020 ◽  
Author(s):  
Shuo Mao ◽  
Ridge A. Sibold ◽  
Stephen Lash ◽  
Wing F. Ng ◽  
Hongzhou Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Mass Flux ◽  
Guide Vane ◽  
Density Ratio ◽  
Momentum Ratio ◽  
Blowing Ratio ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
The Impact

Abstract Nozzle guide vane platforms often employ complex cooling schemes to mitigate ever-increasing thermal loads on endwall. Understanding the impact of advanced cooling schemes amid the highly complex three-dimensional secondary flow is vital to engine efficiency and durability. This study analyzes and describes the effect of coolant to mainstream blowing ratio, momentum ratio and density ratio for a typical axisymmetric converging nozzle guide vane platform with an upstream doublet staggered, steep-injection, cylindrical hole jet purge cooling scheme. Nominal flow conditions were engine representative and as follows: Maexit = 0.85, Reexit/Cax = 1.5 × 106 and an inlet large-scale freestream turbulence intensity of 16%. Two blowing ratios were investigated, each corresponding to upper and lower engine extrema at M = 3.5 and 2.5, respectively. For each blowing ratio, the coolant to mainstream density ratio was varied between DR = 1.2, representing typical experimental neglect of coolant density, and DR = 1.95, representative of typical engine conditions. An optimal coolant momentum ratio between = 6.3 and 10.2 is identified for in-passage film effectiveness and net heat flux reduction, at which the coolant suppresses and overcomes secondary flows but imparts minimal turbulence and remains attached to endwall. Progression beyond this point leads to cooling effectiveness degradation and increased endwall heat flux. Endwall heat transfer does not scale well with one single parameter; increasing with increasing mass flux for the low density case but decreasing with increasing mass flux of high density coolant. From the results gathered, both coolant to mainstream density ratio and blowing ratio should be considered for accurate testing, analysis and prediction of purge jet cooling scheme performance.

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