High Intensity, Large Length-Scale Freestream Turbulence Generation in a Transonic Turbine Cascade

2002 ◽  
Author(s):  
A. C. Nix ◽  
A. C. Smith ◽  
T. E. Diller ◽  
W. F. Ng ◽  
K. A. Thole
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
High Intensity ◽  
Turbine Engines ◽  
Length Scale ◽  
Gas Turbine Engines ◽  
Freestream Turbulence ◽  
Large Length ◽  
Scale Turbulence ◽  
Large Length Scale

Heat transfer predictions in gas turbine engines have focused on cooling techniques and on the effects of various flow phenomena. The effects of wakes, passing shock waves and freestream turbulence have all been of primary interest to researchers. The focus of the work presented in this paper is to develop a turbulence grid capable of generating high intensity, large-scale turbulence for use in experimental heat transfer measurements in a transonic facility. The grid is desired to produce freestream turbulence characteristic of the flow exiting the combustor of advanced gas turbine engines. A number of techniques are discussed in this paper to generate high intensity, large length-scale turbulence for a transonic facility. Ultimately, the passive grid design chosen is capable of producing freestream turbulence with intensity of approximately 10–12% near the entrance of the cascade passages with an integral length-scale of 2 cm.

Algorithm of Numerical Checking Calculation of Turbine Cooled Blades of Gas Turbine Engines Using Experimental Data on Heat Transfer and Resistance

2019 ◽  
Vol 62 (2) ◽  
pp. 298-303
Author(s):  
A. V. Il’inkov ◽  
A. M. Ermakov ◽  
V. V. Takmovtsev ◽  
A. V. Shchukin ◽  
A. M. Erzikov
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Gas Turbine ◽  
Turbine Engines ◽  
Gas Turbine Engines

Numerical Investigation of Aerothermal Characteristics of the Blade Tip and Near-Tip Regions of a Transonic Turbine Blade

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
A. Arisi ◽  
S. Xue ◽  
W. F. Ng ◽  
H. K. Moon ◽  
L. Zhang
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Rotor Blade ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Tip Leakage Flow ◽  
Blade Tip ◽  
Exit Mach Number

In modern gas turbine engines, the blade tips and near-tip regions are exposed to high thermal loads caused by the tip leakage flow. The rotor blades are therefore carefully designed to achieve optimum work extraction at engine design conditions without failure. However, very often gas turbine engines operate outside these design conditions which might result in sudden rotor blade failure. Therefore, it is critical that the effect of such off-design turbine blade operation be understood to minimize the risk of failure and optimize rotor blade tip performance. In this study, the effect of varying the exit Mach number on the tip and near-tip heat transfer characteristics was numerically studied by solving the steady Reynolds averaged Navier Stokes (RANS) equation. The study was carried out on a highly loaded flat tip rotor blade with 1% tip gap and at exit Mach numbers of Mexit = 0.85 (Reexit = 9.75 × 105) and Mexit = 1.0 (Reexit = 1.15 × 106) with high freestream turbulence (Tu = 12%). The exit Reynolds number was based on the rotor axial chord. The numerical results provided detailed insight into the flow structure and heat transfer distribution on the tip and near-tip surfaces. On the tip surface, the heat transfer was found to generally increase with exit Mach number due to high turbulence generation in the tip gap and flow reattachment. While increase in exit Mach number generally raises he heat transfer over the whole blade surface, the increase is significantly higher on the near-tip surfaces affected by leakage vortex. Increase in exit Mach number was found to also induce strong flow relaminarization on the pressure side near-tip. On the other hand, the size of the suction surface near-tip region affected by leakage vortex was insensitive to changes in exit Mach number but significant increase in local heat transfer was noted in this region.

Development of high intensity CDC combustor for gas turbine engines

2011 ◽  
Vol 88 (3) ◽  
pp. 963-973 ◽  
Author(s):  
Vaibhav K. Arghode ◽  
Ashwani K. Gupta
Keyword(s):  
Gas Turbine ◽  
High Intensity ◽  
Turbine Engines ◽  
Gas Turbine Engines

Inlet Fogging of Gas Turbine Engines: Part A — Fog Droplet Thermodynamics, Heat Transfer and Practical Considerations

2002 ◽  
Author(s):  
Mustapha Chaker ◽  
Cyrus B. Meher-Homji ◽  
Thomas Mee
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Droplet Size ◽  
Gas Turbines ◽  
Turbine Engines ◽  
Theoretical Studies ◽  
Gas Turbine Engines ◽  
Size Measurement ◽  
The Past ◽  
Experimental And Theoretical Studies

The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade yet not a single technical paper treating the physics and engineering of the fogging process, droplet size measurement, droplet kinetics, or the duct behavior of droplets, from a gas turbine perspective, is available. This paper provides the results of extensive experimental and theoretical studies conducted over several years coupled with practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines ranging in power from 5 to 250 MW. Part A of the paper covers the underlying theory of droplet thermodynamics and heat transfer, and provides several practical pointers relating to the implementation and application of inlet fogging to gas turbine engines.

Numerical Investigation of Aerothermal Characteristics of the Blade Tip and Near-Tip Regions of a Transonic Turbine Blade

2014 ◽  
Author(s):  
A. Arisi ◽  
S. Xue ◽  
W. F. Ng ◽  
H. K. Moon ◽  
L. Zhang
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Rotor Blade ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Tip Leakage Flow ◽  
Blade Tip ◽  
Exit Mach Number

In modern gas turbine engines, the blade tips and near-tip regions are exposed to high thermal loads caused by the tip leakage flow. The rotor blades are therefore carefully designed to achieve optimum work extraction at engine design conditions without failure. However, very often gas turbine engines operate outside these design conditions which might result in sudden rotor blade failure. Therefore, it is critical that the effect of such off-design turbine blade operation be understood to minimize the risk of failure and optimize rotor blade tip performance. In this study, the effect of varying the exit Mach number on the tip and near-tip heat transfer characteristics was numerically studied by solving the steady Reynolds Averaged Navier Stokes (RANS) equation. The study was carried out on a highly loaded flat tip rotor blade with 1% tip gap and at exit Mach numbers of Mexit = 0.85 (Reexit = 9.75 × 105) and Mexit = 1.0 (Reexit = 1.15 × 106) with high freestream turbulence (Tu = 12%). The exit Reynolds number was based on the rotor axial chord. The numerical results provided detailed insight into the flow structure and heat transfer distribution on the tip and near-tip surfaces. On the tip surface, the heat transfer was found to generally increase with exit Mach number due to high turbulence generation in the tip gap and flow reattachment. While increase in exit Mach number generally raises he heat transfer over the whole blade surface, the increase is significantly higher on the near-tip surfaces affected by leakage vortex. Increase in exit Mach number was found to also induce strong flow relaminarisation on the pressure side near-tip. On the other hand, the size of the suction surface near-tip region affected by leakage vortex was insensitive to changes in exit Mach number but significant increase in local heat transfer was noted in this region.

Inlet Fogging of Gas Turbine Engines—Part I: Fog Droplet Thermodynamics, Heat Transfer, and Practical Considerations

2004 ◽  
Vol 126 (3) ◽  
pp. 545-558 ◽  
Author(s):  
Mustapha Chaker ◽  
Cyrus B. Meher-Homji ◽  
Thomas Mee
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Droplet Size ◽  
Gas Turbines ◽  
Turbine Engines ◽  
Theoretical Studies ◽  
Gas Turbine Engines ◽  
Size Measurement ◽  
The Past ◽  
Experimental And Theoretical Studies

The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade yet not a single technical paper treating the physics and engineering of the fogging process, droplet size measurement, droplet kinetics, or the duct behavior of droplets, from a gas turbine perspective, is available. This paper provides the results of extensive experimental and theoretical studies conducted over several years coupled with practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines ranging in power from 5 to 250 MW. Part I of the paper covers the underlying theory of droplet thermodynamics and heat transfer, and provides several practical pointers relating to the implementation and application of inlet fogging to gas turbine engines.

scholarly journals A Review of the Bases of Predicting Heat Transfer to Gas Turbine Rotor Blades

1974 ◽  
Author(s):  
A. Brown ◽  
B. W. Martin
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Mainstream Flow ◽  
Streamwise Pressure Gradient

This paper reviews the methods for predicting boundary-layer behavior on flat and curved surfaces under conditions experienced in gas turbine engines and the resultant heat transfer to the turbine rotor blades. Particular attention is given to the effects of streamwise pressure gradient and the intensity of mainstream turbulence on transition phenomena. The time-mean heat transfer across a boundary-layer under unidirectional oscillatory mainstream flow, such as might be initiated in a combustion chamber, is considered. The relevance of flat plate predictions and correlations to rotating turbine blades is also discussed.

Understanding Unsteady Flow Behaviour in a Low Aspect Ratio Contra-Rotating Axial Fan Under Radially Distorted Inflow

2019 ◽  
Author(s):  
Manas Madasseri Payyappalli ◽  
A. M. Pradeep
Keyword(s):  
Aspect Ratio ◽  
Unsteady Flow ◽  
Gas Turbine ◽  
Pressure Sensors ◽  
Pressure Rise ◽  
Wire Mesh ◽  
Turbine Engines ◽  
Length Scale ◽  
Gas Turbine Engines ◽  
Low Aspect Ratio

Abstract Contra-rotation has several advantages like swirl-free discharge, high pressure-rise per stage, and possibility of operating both the rotors at different speeds. With these merits, contra-rotating fan emerges as a competent technology for future gas turbine engines. During operation, gas turbine engines undergo situations like high angle of attack manoeuvres, large cross-winds, bird-hits, etc. which distort the flow at the inlet of the engine. A thorough understanding of the effect of distortion on low aspect ratio contra-rotating fans is missing in literature. This paper reports the consequences of radial distortion on the performance of a low aspect ratio contra-rotating fan. The uniform inlet flow is distorted radially using wire mesh screens. The unsteady data obtained from high response pressure sensors are analysed using Discrete Spatial Fourier Series (DSFS) and Morlet wavelet transform. Both Long Length Scale Disturbances (LLSD) or modal waves and Short Length Scale Disturbances (SLSD) or spikes are observed for different inflow conditions. The stage stalls primarily due to the instabilities arising at the tip region of rotor-1. Rotor-2 shows poor coherence in the disturbances prior to stall compared to that of rotor-1. Tip-distorted flow is dominated with SLSDs in the pre-stall region and hence a stall precursor is not observed whereas clean and hub-distorted flows show prominent LLSDs prior to stall. The radial distortions get redistributed at the exit of rotor-1 and hence, the distorted inflows do not severely lead to instabilities on rotor-2. In summary, this work explains in detail the development of unsteady flow phenomena occurring in a low-aspect ratio contra-rotating fan stage leading to stall and the way in which the system responds to it.

scholarly journals Effect of High Freestream Turbulence With Large Length Scale on Blade Heat/Mass Transfer

1998 ◽  
Author(s):  
H. P. Wang ◽  
R. J. Goldstein ◽  
S. J. Olson
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Mass Transfer Rate ◽  
Reynolds Numbers ◽  
Boundary Layer Transition ◽  
Length Scale ◽  
Freestream Turbulence ◽  
Large Length ◽  
Large Length Scale

The naphthalene sublimation technique is used to investigate the influence of high freestream turbulence with large length scale on the heat/mass transfer from a turbine blade in a highly accelerated linear cascade. The experiments are conducted at four exit Reynolds numbers, ranging from 2.4 × 105 to 7.8 × 105, with freestream turbulence of 3%, 8.5% and 18% and corresponding integral length scales of 0.9 cm, 2.6 cm and 8 cm, respectively. On the suction surface, the heat/mass transfer rate is significantly enhanced by high freestream turbulence due to an early boundary layer transition. By contrast, the transition occurs very late, and may not occur at very low Reynolds numbers with low freestream turbulence. In the turbulent boundary layer, lower heat/mass transfer rates are found for the highest freestream turbulence level with large length scale than for the moderate turbulence levels with relatively small scales. Similar phenomena also occur at the leading edge. However, the effect of turbulence is not as pronounced in the laminar boundary layer.

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