Application of Film Cooling to an Unshrouded HP Turbine Casing

2016 ◽  
Author(s):  
Matthew Collins ◽  
Kamaljit Chana ◽  
Thomas Povey
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Experimental Testing ◽  
Validation Data ◽  
Time Resolved ◽  
Leakage Flows ◽  
Acoustic Pressure Wave ◽  
Turbine Casing ◽  
And Performance ◽  
Tip Leakage Flows

In this paper we describe the design, modelling and experimental testing of a film cooling scheme employed on an unshrouded HP rotor casing. The casing region has high thermal loads at both low and high frequency, with the flow being dominated by the potential field of the rotor and over-tip leakage flows. Increasingly high turbine entry temperatures necessitate internal and film cooling of the casing to ensure satisfactory service life and performance. There are, however, very few published studies presenting CFD and experimental data for cooled rotor casings. Experimental testing was performed on a film cooled rotor casing in the Oxford Turbine Research Facility (OTRF) — a rotating transonic facility of engine scale. Unsteady CFD of a HP rotor blade row with a film cooled casing was performed with a domain utilizing a sliding interface in the tip gap. Specific advances in validation data and understanding include: 1. A discussion of the challenges faced in the design of a casing film cooling scheme. We show that the seemingly hostile film cooling environment can be managed with the use of holes shaped to utilize acoustic pressure wave reflections. 2. Time resolved and time averaged predictions of adiabatic film effectiveness on the rotor casing are presented. Mechanisms for interaction of the coolant with the rotor tip are proposed and discussed. 3. Acoustic effects due to the passing of the rotor are demonstrated on a 3D CFD geometry, supporting conclusions drawn by Collins and Povey [1] on the importance of this effect in a casing film cooling system. 4. Time-resolved and time-mean measurements of TAW and η’ taken using a high density array of thin film heat flux gauges are presented and compared to CFD predictions for the casing region (−30 % to +125 % CAX).

Application of Film Cooling to an Unshrouded High-Pressure Turbine Casing

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Matthew Collins ◽  
Kamaljit Chana ◽  
Thomas Povey
Keyword(s):  
High Pressure ◽  
Film Cooling ◽  
Cooling System ◽  
Experimental Testing ◽  
Adiabatic Wall ◽  
Time Resolved ◽  
Film Cooling Effectiveness ◽  
Leakage Flows ◽  
And Performance ◽  
Tip Leakage Flows

In this paper, we describe the design, modeling, and experimental testing of a film cooling scheme employed on an unshrouded high-pressure (HP) rotor casing. The casing region has high thermal loads at both low and high frequency, with the flow being dominated by the potential field of the rotor and over-tip leakage flows. Increasingly high turbine entry temperatures necessitate internal and film cooling of the casing to ensure satisfactory service life and performance. There are, however, very few published studies presenting computational fluid dynamics (CFD) and experimental data for cooled rotor casings. Experimental testing was performed on a film-cooled rotor casing in the Oxford Turbine Research Facility (OTRF)—a rotating transonic facility of engine scale. Unsteady CFD of an HP rotor blade row with a film-cooled casing was undertaken, uniquely with a domain utilizing a sliding interface in the tip gap. A high density array of thin film heat flux gauges (TFHFGs) was used to obtain time-resolved and time-mean results of adiabatic wall temperature and film cooling effectiveness on the film-cooled rotor casing between −30% and +125% rotor tip axial chord. Results are compared to CFD predictions, and mechanisms for interaction of the coolant with the rotor tip are proposed and discussed. Acoustic effects within casing coolant holes due to the passing of the rotor are demonstrated on a 3D CFD geometry, supporting conclusions drawn in earlier work by the authors on the importance of this effect in a casing film cooling system.

Time-Resolved Flow Field Analysis of Effusion Cooling System With Representative Swirling Main Flow

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
T. Lenzi ◽  
L. Palanti ◽  
A. Picchi ◽  
T. Bacci ◽  
L. Mazzei ◽  
...  
Keyword(s):  
Film Cooling ◽  
Swirling Flow ◽  
Cooling System ◽  
Life Time ◽  
Open Loop ◽  
Main Flow ◽  
Field Analysis ◽  
Ansys Fluent ◽  
Time Resolved ◽  
Film Development

Abstract Film-cooling jets behavior in a combustor chamber is deeply affected by swirling flow interactions and unsteadiness; on the other hand, the jets behavior has a direct impact on different phenomena such as cooling capabilities and ignition. For these reasons, an in-depth characterization of the film-cooling flows in the presence of a swirling main flow and demands dedicated time-resolved analyses. The experimental setup consists of a nonreactive single-sector linear combustor simulator installed in an open-loop wind tunnel. It is equipped with a swirler and a multiperforated plate to simulate the effusion cooling system of the liner. The rig is scaled with respect to the engine configuration to increase spatial resolution and to reduce the characteristic frequencies of the unsteady phenomena. Time-resolved particle image velocimetry (TRPIV) was exploited for the investigation testing different values of liner pressure drop. In addition, numerical investigations were carried out to gain a deeper insight of the behavior highlighted by the experiments and to assess the capability of computational fluid dynamics (CFD) in predicting the flow physics. In this work, the stress-blended eddy simulation (SBES) approach implemented in ansys fluent was adopted. Oscillations of the jets and intermittent interactions of the mainstream with the wall of the liner and hence with the film development have been investigated in detail. The results demonstrate how an unsteady analysis of the flow structures that characterize the jets, the turbulent mixing of coolant flows, and the interaction between mainstream and cooling jets is strictly necessary to have a complete knowledge of the behavior of the coolant, which in turn affects combustor operability and life time.

Controlling Leakage Flows Over a Rotor Blade Tip Using Air-Curtain Injection: Part II — Rotor Casing Film Cooling

2019 ◽  
Author(s):  
Qiang Zhao ◽  
Xing Yang ◽  
Zhao Liu ◽  
Zhenping Feng ◽  
Terrence W. Simon
Keyword(s):  
Film Cooling ◽  
Leading Edge ◽  
Cooling Effectiveness ◽  
Air Curtain ◽  
Film Cooling Effectiveness ◽  
Tip Leakage ◽  
Leakage Flows ◽  
Blade Tip ◽  
Tip Injection ◽  
Tip Leakage Flows

Abstract In modern gas turbine engines, the rotor casing region experiences high thermal loads due to complex flow structures and aerothermal effects. Thus, casing cooling is one of essential measures to ensure turbine service lifetime and performance. However, studies on heat transfer and cooling over the rotor casing with tip leakage flows are limited in the open literature during the past decades. The present work aims at controlling leakage flows over the blade tip and decreasing heat loads on the rotor casing. A novel approach proposed in a companion paper (GT2019-90232) is adopted in this paper as Part II by introducing an air-curtain injection from the rotor casing through a pair of inclined rows of discrete holes positioned in the range of 30% and 50% axial chord downstream of the blade leading edge in the casing. This air-curtain injection approach is applied to flat and recessed tips with and without tip injection to evaluate its sealing capability on tip leakage flows and film cooling effectiveness on the casing for two injection ratios of 0.7% and 1.0%. In this paper, Reynolds-averaged Navier-Stokes (RANS) simulations with Shear Stress Transport (SST) k-ω turbulence model and γ-Reθ transition model, which are validated with relevant experimental data, are performed to investigate tip leakage flows and film cooling effectiveness on the casing in a single-stage, high-pressure gas turbine engine. Results show that casing injection can reduce tip leakage mass flow effectively by changing the development and migration of tip leakage mass flows, especially when the recessed tip is applied. Adding tip injection would further reduces the tip leakage. The casing injection also provides an excellent cooling effect on the casing across rotor middle chord through trailing edge regions. In the presence of the recessed tip, coolant spreads out well on the rotor tip and the casing surfaces, resulting in better film cooling effectiveness on the casing over rotor tip leading edge. In addition, the tip injection could provide an extra cooling effect in some other regions of the casing.

Analysis of Swirl number effects on effusion flow behaviour using time resolved PIV

2022 ◽  
pp. 1-33
Author(s):  
Tommaso Lenzi ◽  
Alessio Picchi ◽  
Antonio Andreini ◽  
Bruno Facchini
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Tangential Velocity ◽  
Particle Image Velocimetry System ◽  
Swirl Number ◽  
Time Resolved ◽  
Experimental Apparatus ◽  
Turbulence Length ◽  
The Impact ◽  
Near Wall

Abstract The analysis of the interaction between the swirling and liner film-cooling flows is a fundamental task for the design of turbine combustion chambers since it influences different aspects such as emissions and cooling capability. Particularly, high turbulence values, flow instabilities, and tangential velocity components induced by the swirlers deeply affect the behavior of effusion cooling jets, demanding for dedicated time-resolved near-wall analysis. The experimental setup of this work consists of a non-reactive single-sector linear combustor test rig scaled up with respect to engine dimensions; the test section was equipped with an effusion plate with standard inclined cylindrical holes to simulate the liner cooling system. The rig was instrumented with a 2D Time-Resolved Particle Image Velocimetry system, focused on different field of views. The degree of swirl is usually characterized by the swirl number, Sn, defined as the ratio of the tangential momentum to axial momentum flux. To assess the impact of such parameter on the near-wall effusion behavior, a set of three axial swirlers with swirl number equal to Sn = 0.6 − 0.8 − 1.0 were designed and tested in the experimental apparatus. An analysis of the main flow by varying the Sn was first performed in terms of average velocity, RMS, and Tu values, providing kinetic energy spectra and turbulence length scale information. Following, the analysis was focused on the near-wall regions: the effects of Sn on the coolant jets was quantified in terms of vorticity analysis and jet oscillation.

scholarly journals Unsteady Flow Field Characterization of Effusion Cooling Systems with Swirling Main Flow: Comparison Between Cylindrical and Shaped Holes

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4993
Author(s):  
Tommaso Lenzi ◽  
Alessio Picchi ◽  
Tommaso Bacci ◽  
Antonio Andreini ◽  
Bruno Facchini
Keyword(s):  
Flow Field ◽  
Film Cooling ◽  
Gas Turbines ◽  
Swirling Flow ◽  
Cooling System ◽  
Complete Characterization ◽  
Time Resolved ◽  
Staggered Arrangement ◽  
Unsteady Characteristics

The presence of injectors with strongly swirled flows, used to promote flame stability in the combustion chambers of gas turbines, influences the behaviour of the effusion cooling jets and consequently of the liner’s cooling capabilities. For this reason, unsteady behaviour of the jets in the presence of swirling flow requires a characterization by means of experimental flow field analyses. The experimental setup of this work consists of a non-reactive single-sector linear combustor test rig, scaled up with respect to the real engine geometry to increase spatial resolution and to reduce the frequencies of the unsteadiness. It is equipped with a radial swirler and multi-perforated effusion plates to simulate the liner cooling system. Two effusion plates were tested and compared: with cylindrical and with laid-back fan-shaped 7-7-7 holes in staggered arrangement. Time resolved Particle Image Velocimetry has been carried out: the unsteady characteristics of the jets, promoted by the intermittent interactions with the turbulent mainstream, have been investigated as their vortex structures and turbulent decay. The results demonstrate how an unsteady analysis is necessary to provide a complete characterization of the coolant behaviour and of its turbulent mixing with mainflow, which affect, in turn, the film cooling capability and liner’s lifetime.

Time-Resolved Flow Field Analysis of Effusion Cooling System With Representative Swirling Main Flow

2019 ◽  
Author(s):  
T. Lenzi ◽  
L. Palanti ◽  
A. Picchi ◽  
T. Bacci ◽  
L. Mazzei ◽  
...  
Keyword(s):  
Film Cooling ◽  
Swirling Flow ◽  
Cooling System ◽  
Life Time ◽  
Open Loop ◽  
Field Analysis ◽  
Ansys Fluent ◽  
Time Resolved ◽  
Eddy Simulation ◽  
Film Development

Abstract Film cooling jets behaviour in a combustor chamber is deeply affected by swirling flow interactions and unsteadiness; on the other hand, the jets behaviour has a direct impact on different phenomena such as cooling capabilities and ignition. For these reasons, an in-depth characterization of the film-cooling flows in the presence of a swirling mainflow, demands dedicated time-resolved analyses. The experimental setup consists of a non-reactive single-sector linear combustor simulator installed in an open loop wind tunnel. It is equipped with a swirler and a multiperforated plate to simulate the effusion cooling system of the liner. The rig is scaled with respect to the engine configuration, to increase spatial resolution and to reduce the characteristic frequencies of the unsteady phenomena. Time-Resolved Particle Image Velocimetry (TRPIV) was exploited for the investigation testing different values of liner pressure drop. In addition, numerical investigations were carried out to gain a deeper insight of the behaviour highlighted by the experiments and to assess the capability of CFD in predicting the flow physics. In this work, the Stress-Blended Eddy Simulation (SBES) approach implemented in ANSYS Fluent was adopted. Oscillations of the jets and intermittent interactions of the mainstream with the wall of the liner and hence with the film development have been investigated in detail. The results demonstrate how an unsteady analysis of the flow structures that characterize the jets, the turbulent mixing of coolant flows and the interaction between mainstream and cooling jets is strictly necessary to have a complete knowledge of the behaviour of the coolant which in turn affects combustor operability and life-time.

Spray Cooling for Time Resolved Emission Measurements of ICs

2004 ◽  
Author(s):  
Rama R. Goruganthu ◽  
David Bethke ◽  
Shawn McBride ◽  
Tom Crawford ◽  
Jonathan Frank ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Performance ◽  
Flip Chip ◽  
Cooling System ◽  
Spray Cooling ◽  
Junction Temperature ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
High Heat Flux ◽  
Time Resolved

Abstract Spray cooling is implemented on an engineering tool for Time Resolved Emission measurements using a silicon solid immersion lens to achieve high spatial resolution and for probing high heat flux devices. Thermal performance is characterized using a thermal test vehicle consisting of a 4x3 array of cells each with a heater element and a thermal diode to monitor the temperature within the cell. The flip-chip packaged TTV is operated to achieve uniform heat flux across the die. The temperature distribution across the die is measured on the 4x3 grid of the die for various heat loads up to 180 W with corresponding heat flux of 204 W/cm2. Using water as coolant the maximum temperature differential across the die was about 30 °C while keeping the maximum junction temperature below 95 °C and at a heat flux of 200 W/cm2. Details of the thermal performance of spray cooling system as a function of flow rate, coolant

Field Determined Live Load Distribution Factors for Modular Press-Brake-Formed Tub Girders

2021 ◽  
pp. 036119812098375
Author(s):  
Karl E. Barth ◽  
Gregory K. Michaelson ◽  
Adam D. Roh ◽  
Robert M. Tennant
Keyword(s):  
West Virginia ◽  
Experimental Testing ◽  
Field Performance ◽  
Live Load ◽  
Steel Bridge ◽  
Testing Procedures ◽  
Bending Capacity ◽  
Short Span ◽  
And Performance ◽  
Live Load Distribution

This paper is focused on the field performance of a modular press-brake-formed tub girder (PBFTG) system in short span bridge applications. The scope of this project to conduct a live load field test on West Virginia State Project no. S322-37-3.29 00, a bridge utilizing PBFTGs located near Ranger, West Virginia. The modular PBFTG is a shallow trapezoidal box girder cold-formed using press-brakes from standard mill plate widths and thicknesses. A technical working group within the Steel Market Development Institute’s Short Span Steel Bridge Alliance, led by the current authors, was charged with the development of this concept. Research of PBFTGs has included analyzing the flexural bending capacity using experimental testing and analytical methods. This paper presents the experimental testing procedures and performance of a composite PBFTG bridge.

Blade Lean and Tip Leakage Flows in Highly Loaded Compressor Cascades

2021 ◽  
Vol 30 (4) ◽  
pp. 1388-1405
Author(s):  
Zhiyuan Cao ◽  
Cheng Song ◽  
Xiang Zhang ◽  
Xi Gao ◽  
Bo Liu
Keyword(s):  
Tip Leakage ◽  
Leakage Flows ◽  
Tip Leakage Flows ◽  
Highly Loaded
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