scholarly journals Transient Aero-Thermo-Mechanical Multidimensional Analysis of a High Pressure Turbine Assembly Through a Square Cycle

2021 ◽  
Author(s):  
Vladislav Ganine ◽  
John W. Chew ◽  
Nicholas Hills ◽  
Sulfi Noor Mohamed ◽  
Matthew Miller
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Network Code ◽  
Multidimensional Analysis ◽  
High Pressure Turbine ◽  
Time Step ◽  
Local Flow ◽  
Area Of Interest ◽  
Engine Components ◽  
Cooling Air

Abstract Better understanding and more accurate prediction of heat transfer and cooling flows in aero engine components in steady and transient operating regimes are essential to modern engine designs aiming at reduced cooling air consumption and improved engine efficiencies. This paper presents a simplified coupled transient analysis methodology that allows assessment of the aerothermal and thermomechanical responses of engine components together with cooling air mass flow, pressure and temperature distributions in an automatic fully integrated way. This is achieved by assembling a fluid network with contribution of components of different geometrical dimensions coupled to each other through dimensionally heterogeneous interfaces. More accurate local flow conditions, heat transfer and structural displacement are resolved on a smaller area of interest with multidimensional surface coupled CFD/FE codes. Contributions of the whole engine air-system are predicted with a faster mono dimensional flow network code. Matching conditions at the common interfaces are enforced at each time step exactly by employing an efficient iterative scheme. The coupled simulation is performed on an industrial high pressure turbine disk component run through a square cycle. Predictions are compared against the available experimental data. The paper proves the reliability and performance of the multidimensional coupling technique in a realistic industrial setting. The results underline the importance of including more physical details into transient thermal modelling of turbine engine components.

scholarly journals Transient Aero-Thermo-Mechanical Multidimensional Analysis of a High Pressure Turbine Assembly Through a Square Cycle

2020 ◽  
Author(s):  
Vlad Ganine ◽  
John W. Chew ◽  
Nicholas J. Hills ◽  
Sulfi N. Mohamed ◽  
Matthew M. Miller
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Network Code ◽  
Multidimensional Analysis ◽  
High Pressure Turbine ◽  
Time Step ◽  
Local Flow ◽  
Area Of Interest ◽  
Engine Components ◽  
Cooling Air

Abstract Better understanding and more accurate prediction of heat transfer and cooling flows in aero engine components in steady and transient operating regimes are essential to modern engine designs aiming at reduced cooling air consumption and improved engine efficiencies. This paper presents a simplified coupled transient analysis methodology that allows assessment of the aerothermal and thermomechanical responses of engine components together with cooling air mass flow, pressure and temperature distributions in an automatic fully integrated way. This is achieved by assembling a fluid network with contribution of components of different geometrical dimensions coupled to each other through dimensionally heterogeneous interfaces. More accurate local flow conditions, heat transfer and structural displacement are resolved on a smaller area of interest with multidimensional surface coupled CFD/FE codes. Contributions of the whole engine air-system are predicted with a faster mono dimensional flow network code. Matching conditions at the common interfaces are enforced at each time step exactly by employing an efficient iterative scheme. The coupled simulation is performed on an industrial high pressure turbine disk component run through a square cycle. Predictions are compared against the available experimental data. The paper proves the reliability and performance of the multidimensional coupling technique in a realistic industrial setting. The results underline the importance of including more physical details into transient thermal modelling of turbine engine components.

Flow Topology Optimization of a Cooling Passage for a High Pressure Turbine Blade

2017 ◽  
Author(s):  
J. Iseler ◽  
T. J. Martin
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Topology Optimization ◽  
Pressure Loss ◽  
High Pressure Turbine ◽  
Flow Topology ◽  
Local Flow ◽  
Design Modification ◽  
Cooling Passage ◽  
The Impact

This paper deals with a topology optimization of internal cooling passages within high pressure turbine blades in order to deliver fully three dimensional designs that optimize the local flow physics. By applying the implemented optimality criteria, a new individual passage design with minimized amount of recirculation is achieved, leading to a reduced total pressure loss. In contrary to traditional parametric approaches, where a CFD run is needed after each design modification, the applied topology optimization acts as a co-simulation and is finished after a single run where the initial geometry represents the available design space. The CFD runs for optimization and the subsequent verification of the flow passages assume steady state take-off conditions. The verification includes a flow simulation to check the pressure loss of the optimized passage design. In a second step, a loosely coupled conjugate heat transfer procedure including external turbine flow, coolant flow and heat conduction of the solid (blade, platform and attachment) is applied to predict the impact on the heat transfer. By running a FEM simulation afterwards, the stresses are computed and compared with those from the reference design.

A Large Scale Turbine Test Rig for the Investigation of High Pressure Turbine Aerodynamics and Heat Transfer With Variable Inflow Conditions

2015 ◽  
Author(s):  
Alexander Krichbaum ◽  
Holger Werschnik ◽  
Manuel Wilhelm ◽  
Heinz-Peter Schiffer ◽  
Knut Lehmann
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Large Scale ◽  
Measurement Techniques ◽  
Air Injection ◽  
Test Rig ◽  
High Pressure Turbine ◽  
Film Cooling Effectiveness ◽  
Cooling Air ◽  
Inflow Conditions

Focusing on the experimental analysis of the effect of variable inlet flows on aerodynamics, efficiency and heat transfer of a modern high pressure turbine, the Large Scale Turbine Rig (LSTR) at Technische Universität Darmstadt has been extensively redesigned. The LSTR is a full annular, rotating low speed turbine test rig carrying a scaled 1.5-stage (NGV1 - Rotor - NGV2) axial high-pressure turbine geometry designed by Rolls-Royce Deutschland to match engine-realistic Reynolds numbers. To simulate real turbine inflow conditions, the LSTR is equipped with a combustor simulator module including exchangeable swirlers. Other inflow conditions include axial or turbulent inflow as well as altered relative positions of swirl cores and NGVs by traversing. To investigate combustor-turbine interaction, the LSTR offers a large variety of optical and physical access ports as well as high flexibility to the application of measurement techniques. An elaborate secondary air system enables the simulation of various cooling air flows. The turbine section is equipped with film-cooled NGVs, a hub side seal air injection between NGVs and rotor, as well as a hub side RIDN cooling air injection module designed to provide realistic turbine flow conditions. Exchangeable hub side RIDN-plates allow for investigation of different coolant injection geometries. Measurement capabilities include 5-hole-probes, Pitot and total temperature rakes, as well as static pressure taps distributed along NGV radial sections and at the hub side passage endwall. The NGV passage flow can be visualized by means of Particle Image Velocimetry (PIV). Hot Wire Anemometry (HWA) will be used for time-resolved measurements of the turbulence level at several positions. The distributions of heat transfer and film cooling effectiveness are acquired using infrared thermography and CO2-gas tracing.

Effects of Combustor Exit Profiles on Vane Aerodynamic Loading and Heat Transfer in a High Pressure Turbine

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
M. D. Barringer ◽  
K. A. Thole ◽  
M. D. Polanka
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Total Pressure ◽  
Temperature Profiles ◽  
High Pressure Turbine ◽  
Local Flow ◽  
Aerodynamic Loading ◽  
Turbine Inlet ◽  
Pressure Profiles ◽  
Total Temperature

The flow and thermal fields exiting gas turbine combustors dictate the overall performance of the downstream turbine. The goal of this work was to investigate the effects of engine representative combustor exit profiles on high pressure turbine vane aerodynamics and heat transfer. The various profiles were produced using a nonreacting turbine inlet profile generator in the Turbine Research Facility (TRF) located at the Air Force Research Laboratory (AFRL). This paper reports how the pressure loading and heat transfer along the vane surface was affected by different turbine inlet pressure and temperature profiles at different span locations. The results indicate that the inlet total pressure profiles affected the aerodynamic loading by as much as 10%. The results also reveal that the combination of different total pressure and total temperature profiles significantly affected the vane heat transfer relative to a baseline test with uniform inlet total pressure and total temperature. Near the inner diameter endwall, the baseline heat transfer was reduced 30–40% over the majority of the vane surface. Near the outer dimeter endwall, it was found that certain inlet profiles could increase the baseline heat transfer by 10–20%, while other profiles resulted in a decrease in the baseline heat transfer by 25–35%. This study also shows the importance of knowing an accurate prediction of the local flow driving temperature when determining vane surface heat transfer.

Heat Transfer and Aerodynamics of Over-Shroud Leakage Flows in a High-Pressure Turbine

2009 ◽  
Author(s):  
Knut Lehmann ◽  
Richard Thomas ◽  
Howard Hodson ◽  
Vassilis Stefanis
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Large Scale ◽  
Suction Side ◽  
Surface Flow ◽  
Tip Clearance ◽  
Flow Visualisation ◽  
Leakage Flow ◽  
High Pressure Turbine ◽  
High Heat Transfer

An experimental study has been conducted to investigate the distribution of the convective heat transfer on the shroud of a high pressure turbine blade in a large scale rotating rig. A continuous thin heater foil technique has been adapted and implemented on the turbine shroud. Thermochromic Liquid Crystals were employed for the surface temperature measurements to derive the experimental heat transfer data. The heat transfer is presented on the shroud top surfaces and the three fins. The experiments were conducted for a variety of Reynolds numbers and flow coefficients. The effects of different inter-shroud gap sizes and reduced fin tip clearance gaps were also investigated. Details of the shroud flow field were obtained using an advanced Ammonia-Diazo surface flow visualisation technique. CFD predictions are compared with the experimental data and used to aid interpretation. Contour maps of the Nusselt number reveal that regions of highest heat transfer are mostly confined to the suction side of the shroud. Peak values exceed the average by as much as 100 percent. It has been found that the interaction between leakage flow through the inter-shroud gaps and the fin tip leakage jets are responsible for this high heat transfer. The inter-shroud gap leakage flow causes a disruption of the boundary layer on the turbine shroud. Furthermore, the development of the large recirculating shroud cavity vortices is severely altered by this leakage flow.

Numerical Simulations of Heat Transfer and Fluid Flow for a Rotating High-Pressure Turbine

2006 ◽  
Author(s):  
F. Mumic ◽  
L. Ljungkruna ◽  
B. Sunden
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Fluid Flow ◽  
Numerical Study ◽  
Three Dimensional ◽  
Turbulence Models ◽  
High Pressure Turbine ◽  
Experimental Heat ◽  
Commercial Code ◽  
Stator Vane

In this work, a numerical study has been performed to simulate the heat transfer and fluid flow in a transonic high-pressure turbine stator vane passage. Four turbulence models (the Spalart-Allmaras model, the low-Reynolds-number realizable k-ε model, the shear-stress transport (SST) k-ω model and the v2-f model) are used in order to assess the capability of the models to predict the heat transfer and pressure distributions. The simulations are performed using the FLUENT commercial software package, but also two other codes, the in-house code VolSol and the commercial code CFX are used for comparison with FLUENT results. The results of the three-dimensional simulations are compared with experimental heat transfer and aerodynamic results available for the so-called MT1 turbine stage. It is observed that the predictions of the vane pressure field agree well with experimental data, and that the pressure distribution along the profile is not strongly affected by choice of turbulence model. It is also shown that the v2-f model yields the best agreement with the measurements. None of the tested models are able to predict transition correctly.

The Influence of Purge Flow Parameters on Heat Transfer and Film Cooling in Turbine Center Frames

2021 ◽  
Author(s):  
Patrick R. Jagerhofer ◽  
Marios Patinios ◽  
Tobias Glasenapp ◽  
Emil Göttlich ◽  
Federica Farisco
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Convective Heat Transfer Coefficient ◽  
Density Ratio ◽  
Constant Heat Flux ◽  
High Pressure Turbine ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Purge Flow

Abstract Due to stringent environmental legislation and increasing fuel costs, the efficiencies of modern turbofan engines have to be further improved. Commonly, this is facilitated by increasing the turbine inlet temperatures in excess of the melting point of the turbine components. This trend has reached a point where not only the high-pressure turbine has to be adequately cooled, but also components further downstream in the engine. Such a component is the turbine center frame (TCF), having a complex aerodynamic flow field that is also highly influenced by purge-mainstream interactions. The purge air, being injected through the wheelspace cavities of the upstream high-pressure turbine, bears a significant cooling potential for the TCF. Despite this, fundamental knowledge of the influencing parameters on heat transfer and film cooling in the TCF is still missing. This paper examines the influence of purge-to-mainstream blowing ratio, purge-to-mainstream density ratio and purge flow swirl angle on the convective heat transfer coefficient and the film cooling effectiveness in the TCF. The experiments are conducted in a sector-cascade test rig specifically designed for such heat transfer studies using infrared thermography and tailor-made flexible heating foils with constant heat flux. The inlet flow is characterized by radially traversing a five-hole-probe. Three purge-to-mainstream blowing ratios and an additional no purge case are investigated. The purge flow is injected without swirl and also with engine-similar swirl angles. The purge swirl and blowing ratio significantly impact the magnitude and the spread of film cooling in the TCF. Increasing blowing ratios lead to an intensification of heat transfer. By cooling the purge flow, a moderate variation in purge-to-mainstream density ratio is investigated, and the influence is found to be negligible.

Development of New Single and High-Density Heat-Flux Gauges for Unsteady Heat Transfer Measurements for a Rotating Transonic Turbine

2020 ◽  
Author(s):  
Richard Celestina ◽  
Spencer Sperling ◽  
Louis Christensen ◽  
Randall Mathison ◽  
Hakan Aksoy ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
Pressure Ratio ◽  
High Density ◽  
Secondary Flows ◽  
Single Stage ◽  
High Pressure Turbine ◽  
Transonic Turbine ◽  
New Generation

Abstract This paper presents the development and implementation of a new generation of double-sided heat-flux gauges at The Ohio State University Gas Turbine Laboratory (GTL) along with heat transfer measurements for film-cooled airfoils in a single-stage high-pressure transonic turbine operating at design corrected conditions. Double-sided heat flux gauges are a critical part of turbine cooling studies, and the new generation improves upon the durability and stability of previous designs while also introducing high-density layouts that provide better spatial resolution. These new customizable high-density double-sided heat flux gauges allow for multiple heat transfer measurements in a small geometric area such as immediately downstream of a row of cooling holes on an airfoil. Two high-density designs are utilized: Type A consists of 9 gauges laid out within a 5 mm by 2.6 mm (0.20 inch by 0.10 inch) area on the pressure surface of an airfoil, and Type B consists of 7 gauges located at points of predicted interest on the suction surface. Both individual and high-density heat flux gauges are installed on the blades of a transonic turbine experiment for the second build of the High-Pressure Turbine Innovative Cooling program (HPTIC2). Run in a short duration facility, the single-stage high-pressure turbine operated at design-corrected conditions (matching corrected speed, flow function, and pressure ratio) with forward and aft purge flow and film-cooled blades. Gauges are placed at repeated locations across different cooling schemes in a rainbow rotor configuration. Airfoil film-cooling schemes include round, fan, and advanced shaped cooling holes in addition to uncooled airfoils. Both the pressure and suction surfaces of the airfoils are instrumented at multiple wetted distance locations and percent spans from roughly 10% to 90%. Results from these tests are presented as both time-average values and time-accurate ensemble averages in order to capture unsteady motion and heat transfer distribution created by strong secondary flows and cooling flows.

THE INFLUENCE OF PURGE FLOW PARAMETERS ON HEAT TRANSFER AND FILM COOLING IN TURBINE CENTER FRAMES

2021 ◽  
pp. 1-26
Author(s):  
Patrick René Jagerhofer ◽  
Marios Patinios ◽  
Tobias Glasenapp ◽  
Emil Goettlich ◽  
Federica Farisco
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Density Ratio ◽  
Constant Heat Flux ◽  
Inlet Temperature ◽  
High Pressure Turbine ◽  
Turbofan Engines ◽  
Blowing Ratio ◽  
Purge Flow

Abstract The imperative improvement in the efficiency of turbofan engines is commonly facilitated by increasing the turbine inlet temperature. This development has reached a point where also components downstream of the high-pressure turbine have to be adequately cooled. Such a component is the turbine center frame (TCF), known for a complex aerodynamic flow highly influenced by purge-mainstream interactions. The purge air, being injected through the wheelspace cavities of the upstream high-pressure turbine, bears a significant cooling potential for the TCF. Despite this, fundamental knowledge of the influencing parameters on heat transfer and film cooling in the TCF is still missing. This paper examines the influence of purge-to-mainstream blowing ratio, density ratio and purge swirl angle on heat transfer and film cooling in the TCF. The experiments are conducted in a sector-cascade test rig specifically designed for such heat transfer studies using infrared thermography and tailor-made flexible heating foils with constant heat flux. Three purge-to-mainstream blowing ratios and an additional no purge case are investigated. The purge flow is injected without swirl and also with engine-similar swirl angles. The purge swirl and blowing ratio significantly impact the magnitude and the spread of film cooling in the TCF. Increasing blowing ratios lead to an intensification of heat transfer. By cooling the purge flow, a moderate variation in purge-to-mainstream density ratio is investigated, and the influence is found to be negligible.

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