The Experimental Studies of Improving the Aerodynamic Performance of a Turbine Exhaust System

2014 ◽  
Author(s):  
Stephen Guillot ◽  
Wing F. Ng ◽  
Hans D. Hamm ◽  
Ulrich E. Stang ◽  
Kevin T. Lowe
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Experimental Studies ◽  
Experimental Result ◽  
Test Facility ◽  
Test Rig ◽  
Blow Down ◽  
Recovery Coefficient ◽  
Scale Test ◽  
Turbine Exhaust

Analysis and testing was conducted to optimize an axial diffuser-collector gas turbine exhaust. Two subsonic wind tunnel facilities were designed and built to support this program. A 1/12th scale test rig enabled rapid and efficient evaluation of multiple geometries. This test facility was designed to run continuously at an inlet Mach number of 0.41 and an inlet hydraulic diameter-based Reynolds number of 3.4 × 105. A 1/4th geometric scale test rig was designed and built to validate the data in the 1/12th scale rig. This blow-down rig facilitated testing at a nominally equivalent inlet Mach number, while the Reynolds number was matched to realistic engine conditions via back pressure. Multi-hole pneumatic pressure probes, particle image velocimetry and surface oil flow visualization was deployed in conjunction with computational tools to explore physics-based alterations to the exhaust geometry. The design modifications resulted in a substantial increase in the overall pressure recovery coefficient of +0.07 (experimental result) above the baseline geometry. The optimized performance, first measured at 1/12th scale and obtained using CFD was validated at the full scale Reynolds number.

The Experimental Studies of Improving the Aerodynamic Performance of a Turbine Exhaust System

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Stephen Guillot ◽  
Wing F. Ng ◽  
Hans D. Hamm ◽  
Ulrich E. Stang ◽  
Kevin T. Lowe
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Experimental Studies ◽  
Experimental Result ◽  
Test Facility ◽  
Test Rig ◽  
Blow Down ◽  
Recovery Coefficient ◽  
Scale Test ◽  
Turbine Exhaust

Analysis and testing were conducted to optimize an axial diffuser–collector gas turbine exhaust. Two subsonic wind tunnel facilities were designed and built to support this program. A 1/12th scale test rig enabled rapid and efficient evaluation of multiple geometries. This test facility was designed to run continuously at an inlet Mach number of 0.41 and an inlet hydraulic diameter-based Reynolds number of 3.4 × 105. A 1/4th geometric scale test rig was designed and built to validate the data in the 1/12th scale rig. This blow-down rig facilitated testing at a nominally equivalent inlet Mach number, while the Reynolds number was matched to realistic engine conditions via back pressure. Multihole pneumatic pressure probes, particle image velocimetry (PIV), and surface oil flow visualization were deployed in conjunction with computational tools to explore physics-based alterations to the exhaust geometry. The design modifications resulted in a substantial increase in the overall pressure recovery coefficient of +0.07 (experimental result) above the baseline geometry. The optimized performance, first measured at 1/12th scale and obtained using computational fluid dynamics (CFD) was validated at the full scale Reynolds number.

Temperature Control of Blow-Down, Supersonic Tunnels

1956 ◽  
Vol 60 (541) ◽  
pp. 67-70
Author(s):  
T. A. Thomson
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Reynolds Number ◽  
Mach Number ◽  
Reynolds Numbers ◽  
Stagnation Temperature ◽  
Blow Down ◽  
High Reynolds Numbers ◽  
Experimental Errors ◽  
High Reynolds

The blow-down type of intermittent, supersonic tunnel is attractive because of its simplicity and because relatively high Reynolds numbers can be obtained for a given size of test section. An adverse characteristic, however, is the fall of stagnation temperature during runs, which can affect experiments in several ways. The Reynolds number varies and the absolute velocity is not constant, even if the Mach number and pressure are; heat-transfer cannot be studied under controlled conditions and the experimental errors arising from the effect of heat-transfer on the boundary layer vary in time. These effects can become significant in quantitative experiments if the tunnel is large and the variation of temperature very rapid; the expense required to eliminate them might then be justified.

Investigations of Influential Factors on the Aerodynamic Performance of a Steam Turbine Exhaust System

2010 ◽  
Author(s):  
Jing-Lun Fu ◽  
Jian-Jun Liu
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Exhaust System ◽  
Aerodynamic Performance ◽  
Full Scale ◽  
Small Scale ◽  
Flow Angle ◽  
Fluid Properties ◽  
Turbine Exhaust ◽  
Exhaust Systems

The purpose of this paper is to investigate the influences of different parameters on the three-dimensional flow fields in the low-pressure steam turbine exhaust hood of a typical power station. The complex flows in both small-scale and full-scale turbine exhaust systems under different inlet flow conditions were simulated. The effects of inlet Reynolds number, inlet Mach number and fluid properties on the aerodynamic performance and flow fields in the exhaust systems were analyzed. The influential rules of inlet tangential flow angle distributions in the radial direction for a low speed small-scale model and a full speed full-scale exhaust system were summarized and compared. It is found that the inlet tangential flow angle at different radial position has different effects on the aerodynamic performance for both small-scale and full-scale exhaust systems. The influences of inlet Reynolds number on the aerodynamic performance depend on the inflow swirl conditions. The changing of inlet Mach number leads to the flow pattern variations in the exhaust system. The influences of fluid properties on the exhaust system performance are small.

scholarly journals Experimental Investigation of Stall and Surge in a Multistage Compressor

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Enrico Munari ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Alessio Suman
Keyword(s):  
Mass Flow ◽  
Flow Instability ◽  
Numerical Models ◽  
Characteristic Curve ◽  
Experimental Studies ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Test Facility ◽  
Extensive Literature ◽  
Test Rig

Flow instability conditions, in particular during surge and stall phenomena, have always influenced the operational reliability of turbocompressors and have attracted significant interest resulting in extensive literature. Nowadays, this subject is still one of the most investigated because of its high relevance on centrifugal and axial compressor operating flow range, performance, and efficiency. Many researchers approach this important issue by developing numerical models, whereas others approach it through experimental studies specifically carried out in order to better comprehend this phenomenon. The aim of this paper is to experimentally analyze the stable and unstable operating conditions of an aeronautic turboshaft gas turbine axial–centrifugal compressor installed on a brand new test rig properly designed for this purpose. The test facility is set up in order to obtain (i) the compressor performance maps at rotational speeds up to 25,000 rpm and (ii) the compressor transient behavior during surge. By using two different test rig layouts, instabilities occurring in the compressor, beyond the peak of the characteristic curve, are identified and investigated. These two types of analysis are carried out, thanks to pressure, temperature, and mass flow sensors located in strategic positions along the circuit. These measurement sensors are part of a proper control and acquisition system, characterized by an adjustable sampling frequency. Thus, the desired operating conditions of the compressor in terms of mass flow and rotational speed and transient of these two parameters are regulated by this dedicated control system.

Numerical and Experimental Studies of Reynolds Number and Stator Clocking Effect on Performance of a High-Loaded Two-Stage Compressor With 3.7 Total Pressure Ratio

2016 ◽  
Author(s):  
V. Mileshin ◽  
I. Druzhinin ◽  
N. Savin ◽  
P. Kozhemyako
Keyword(s):  
Reynolds Number ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Experimental Studies ◽  
Inlet Pressure ◽  
Test Facility ◽  
Aerodynamic Load ◽  
Two Stage ◽  
Compressor Efficiency ◽  
Total Pressure Ratio

One of the vital tasks related to the improvement of the efficiency of turbomachines is an increase in their operating altitude by reducing the influence of Reynolds numbers, Re, on the turbomachine parameters. Therefore, the results presented in this work on the effect of Re on parameters of an axial compressor composed of two high-loaded stages are attractive both from scientific and practical points of view. This work presents the results of experimental investigations of Re effect on gas-dynamic characteristics of a highly-loaded two-stage compressor (HPC-2), simulating the first two stages of the High Pressure Compressor, (HPC), for an advanced engine. The compressor has the following key gasdynamic parameters: – corrected mass flow rate: 31.8 kg/s – total pressure ratio: 3.7 – coefficient of aerodynamic load: 0.421 The experimental study of HPC-2 is carried out at the Central Institute of Aviation Motors, (CIAM), C-3 test facility. Reynolds number is changed by decreasing pressure at the inlet from 1 bar to 0.2 bar and changing the clocking position of stator rows at optimal points of performance for two rotational speeds, 0.7 and 0.88. Tests of HPC-2 compressor show that a stepwise decrease of the inlet pressure from 1.0 0.7, 0.4 down to 0.2 bar (a decrease in Re from 1785000 to 294000) leads to a smooth decrease in maximum compressor efficiency by 1% and a shift of compressor characteristics towards lower air flow rates (by 2%). The experimental studies of compressors for present-day engines show that unsteady processes play a key role in compressor efficiency and stability. One way to control unsteady flow in compressors is clocking effect. Recently clocking of stators and rotors has been investigated in details using the HPC-2 two-stage compressor (total pressure ratio 3.7) in H = 0; M = 0 conditions. The effect of Reynolds number on compressor characteristics is studied in this work for the HPC-2 compressor while also investigating stator clocking effect. The rotor clocking effect is not studied. Tests of HPC-2 compressor show that a decrease in the inlet pressure and changes in Re results in a stronger clocking effect, which is 0.5% in terms of efficiency under atmospheric conditions at the inlet and reaches 1% with a decrease in the inlet pressure from atmospheric pressure down to 0.2 bar.

Heat Transfer and Aerodynamics of a High Rim Speed Turbine Nozzle Guide Vane Tested in the RAE Isentropic Light Piston Cascade (ILPC)

1990 ◽  
Author(s):  
S. P. Harasgama ◽  
E. T. Wedlake
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Mach Number ◽  
Guide Vane ◽  
Weak Shock ◽  
Test Facility ◽  
Computational Techniques ◽  
Nozzle Guide ◽  
Annular Cascade ◽  
Nozzle Guide Vanes

Detailed heat transfer and aerodynamic measurements have been made on an annular cascade of highly loaded nozzle guide vanes. The tests were carried out in an Isentropic Light Piston test facility at engine representative Reynolds number, Mach number and gas-to-wall temperature ratio. The aerodynamics indicate that the vane has a weak shock at 65–70% axial chord (mid span) with a peak Mach number of 1.14. The influence of Reynolds number and Mach number on the Nusselt number distributions on the vane and endwall surfaces are shown to be significant. Computational techniques are used for the interpretation of test data.

Heat Transfer and Aerodynamics of a High Rim Speed Turbine Nozzle Guide Vane Tested in the RAE Isentropic Light Piston Cascade (ILPC)

1991 ◽  
Vol 113 (3) ◽  
pp. 384-391 ◽  
Author(s):  
S. P. Harasgama ◽  
E. T. Wedlake
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Mach Number ◽  
Guide Vane ◽  
Weak Shock ◽  
Test Facility ◽  
Computational Techniques ◽  
Nozzle Guide ◽  
Annular Cascade ◽  
Nozzle Guide Vanes

Detailed heat transfer and aerodynamic measurements have been made on an annular cascade of highly loaded nozzle guide vanes. The tests were carried out in an Isentropic Light Piston test facility at engine representative Reynolds number, Mach number, and gas-to-wall temperature ratio. The aerodynamics indicate that the vane has a weak shock at 65–70 percent axial chord (midspan) with a peak Mach number of 1.14. The influence of Reynolds number and Mach number on the Nusselt number distributions on the vane and endwall surfaces are shown to be significant. Computational techniques are used for the interpretation of test data.

Experimental and Numerical Similitude Study Using a Novel Turbocompressor Test Facility Operating With Helium-Neon Gas Mixtures

2021 ◽  
Author(s):  
Maxime Podeur ◽  
Damian M. Vogt
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Specific Heat ◽  
Gas Mixtures ◽  
Test Facility ◽  
Negative Contribution ◽  
Specific Heat Ratio ◽  
Neon Gas ◽  
The Individual ◽  
Helium Neon

Abstract A novel turbocompressor test facility has been designed for helium-neon gas mixtures and its specific features are presented. To account for the heat transfer originating from the motor coolant, a surrogate model has been derived. By combining these results with additional numerical ones, a similitude study is conducted quantifying the individual effects and contributions on efficiency of the Reynolds number, tip Mach number and specific heat ratio. Decoupling the effect of the different parameters shows that their respective contribution on efficiency variation is highly correlated to the Reynolds number actual value. The negative contribution of the tip Mach number and the positive effect of Reynolds number can be used to explain the efficiency variation with increasing tip Mach number. Specific heat ratio variation leads to minor changes in polytropic efficiency except at low tip Mach numbers.

scholarly journals Experimental Investigation of Stall and Surge in a Multistage Compressor

2016 ◽  
Author(s):  
Enrico Munari ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Alessio Suman
Keyword(s):  
Mass Flow ◽  
Flow Instability ◽  
Numerical Models ◽  
Characteristic Curve ◽  
Experimental Studies ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Test Facility ◽  
Extensive Literature ◽  
Test Rig

Flow instability conditions, in particular during surge and stall phenomena, have always influenced the operational reliability of turbo-compressors and have attracted significant interest resulting in extensive literature. Nowadays, this subject is still one of the most investigated because of its high relevance on centrifugal and axial compressor operating flow range, performance and efficiency. Many researchers approach this important issue by developing numerical models, whereas others approach it through experimental studies specifically carried out in order to better comprehend this phenomenon. The aim of this paper is to experimentally analyze the stable and unstable operating conditions of an aeronautic turbo-shaft gas turbine axial-centrifugal compressor installed on a brand new test-rig properly designed for this purpose. The test facility is set up in order to obtain i) the compressor performance maps at rotational speeds up to 25,000 rpm and ii) the compressor transient behavior during surge. By using two different test rig layouts, instabilities occurring in the compressor, beyond the peak of the characteristic curve, are identified and investigated. These two types of analysis are carried out thanks to pressure, temperature and mass flow sensors located in strategic positions along the circuit. These measurement sensors are part of a proper control and acquisition system, characterized by an adjustable sampling frequency. Thus, the desired operating conditions of the compressor, in terms of mass flow and rotational speed and transient of these two parameters are regulated by this dedicated control system.

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