Overall Cooling Effectiveness of Effusion Cooled Can Combustor Liner under Reacting and Non-Reacting Conditions

Abstract Emphasis on lean premixed combustion in modern low NOX combustion chambers limits the air available for cooling the combustion liner. Hence the development of optimized liner cooling designs is imperative for effective usage of available coolant. An effective way to cool a gas turbine combustor liner is through effusion cooling. Effusion cooling (also known as full-coverage film cooling) involves uniformly spaced holes distributed throughout the liner's curved surface area. This paper presents findings from an experimental study on the characterization of the overall cooling effectiveness of an effusion-cooled liner wall, which was representative of a can combustor under heated flow (non-reacting) and lean-combustion (reacting) conditions. The model can-combustor was equipped with an industrial swirler, which subjected the liner walls to engine representative flow and combustion conditions. In this study, two different effusion cooling liners with an inline and staggered arrangement of effusion holes have been studied. These configurations were tested for five different blowing ratios ranging from 0.7 to 4.0 under both reacting and non-reacting conditions. Infrared Thermography (IRT) was used to measure the liner outer surface temperature, and detailed overall effectiveness values were determined under steady-state conditions. From this study, it is clear that the coolant-flame interaction for the reacting experiments significantly impacted the liner cooling effectiveness and led to different overall cooling effectiveness distribution on the liner as compared to the non-reacting experiments.

Overall Cooling Effectiveness of Effusion Cooled Can Combustor Liner Under Reacting and Non-Reacting Conditions

Volume 7A: Heat Transfer ◽

10.1115/gt2020-15221 ◽

2020 ◽

Author(s):

Shoaib Ahmed ◽

Kishore Ranganath Ramakrishnan ◽

Srinath Ekkad ◽

Prashant Singh ◽

Federico Liberatore ◽

...

Keyword(s):

Film Cooling ◽

Combustion Chambers ◽

Cooling Effectiveness ◽

Lean Premixed Combustion ◽

Lean Combustion ◽

Staggered Arrangement ◽

Low Nox Combustion ◽

Combustor Liner ◽

Overall Effectiveness

Abstract Emphasis on lean premixed combustion in modern low NOx combustion chambers limits the availability of air for cooling the combustion liner. Hence the development of optimized liner cooling designs is imperative for effective usage of available coolant. Effusion cooling (also known as full-coverage film cooling) is a common method to cool the combustor liner, which involves uniformly spaced holes distributed throughout the liner curved surface area. This paper presents findings from an experimental study on the characterization of overall cooling effectiveness of an effusion-cooled liner wall, which was representative of a can combustor under heated flow (non-reacting) and lean-combustion (reacting) conditions. The model can-combustor was equipped with an industrial swirler, which subjected the liner walls to engine representative flow and combustion conditions. Inline and staggered arrangement of effusion holes have been studied. These configurations were tested for five different blowing ratios ranging from 0.7 to 4, under both reacting and non-reacting conditions. The experiments were carried out at a constant Reynolds number (based on combustor diameter) of 12,500. Infrared Thermography (IRT) was used to measure the liner outer surface temperature and detailed overall effectiveness values were determined under steady-state conditions. Under non-reacting conditions, the staggered configuration was found to be 9–25% more effective compared to inline configuration. Under reacting conditions, the staggered configuration was be 4–8% more effective compared to inline configuration. It is clear that the coolant-flame interaction for the reacting cases had a significant impact on the liner cooling effectiveness as compared to the non-reacting cases and results in less variation between inline and staggered configurations.

Numerical Investigation of Gas Turbine Combustor Liner Film Cooling Slots

Volume 5C: Heat Transfer ◽

10.1115/gt2018-75608 ◽

2018 ◽

Author(s):

Firat Kiyici ◽

Ahmet Topal ◽

Ender Hepkaya ◽

Sinan Inanli

Keyword(s):

Heat Transfer ◽

Prandtl Number ◽

Surface Temperature ◽

Gas Turbine ◽

Film Cooling ◽

Turbulent Prandtl Number ◽

Surface Cooling ◽

Gas Turbine Combustor ◽

Cooling Effectiveness ◽

A numerical study, based on experimental work of Inanli et al. [1] is conducted to understand the heat transfer characteristics of film cooled test plates that represent the gas turbine combustor liner cooling system. Film cooling tests are conducted by six different slot geometries and they are scaled-up model of real combustor liner. Three different blowing ratios are applied to six different geometries and surface cooling effectiveness is determined for each test condition by measuring the surface temperature distribution. Effects of geometrical and flow parameters on cooling effectiveness are investigated. In this study, Conjugate Heat Transfer (CHT) simulations are performed with different turbulence models. Effect of the turbulent Prandtl Number is also investigated in terms of heat transfer distribution along the measurement surface. For this purpose, turbulent Prandtl number is calculated with a correlation as a function of local surface temperature gradient and its effect also compared with the constant turbulent Prandtl numbers. Good agreement is obtained with two-layered k–ϵ with modified Turbulent Prandtl number.

Account of Film Turbulence for Predicting Film Cooling Effectiveness in Gas Turbine Combustors

Volume 1B: Gas Turbines ◽

10.1115/79-gt-200 ◽

1979 ◽

Author(s):

G. J. Sturgess

Keyword(s):

Gas Turbine ◽

Film Cooling ◽

Cooling Effectiveness ◽

Turbine Engine ◽

Wide Range ◽

Engine Combustion ◽

Turbulence Effects ◽

The Impact ◽

The paper deals with a small but important part of the overall gas turbine engine combustion system and continues earlier published work on turbulence effects in film cooling to cover the case of film turbulence. Film cooling of the gas turbine combustor liner imposes certain geometric limitations on the coolant injection device. The impact of practical film injection geometry on the cooling is one of increased rates of film decay when compared to the performance from idealized injection geometries at similar injection conditions. It is important to combustor durability and life estimation to be able to predict accurately the performance obtainable from a given practical slot. The coolant film is modeled as three distinct regions, and the effects of injection slot geometry on the development of each region are described in terms of film turbulence intensity and initial circumferential non-uniformity of the injected coolant. The concept of the well-designed slot is introduced and film effectiveness is shown to be dependent on it. Only slots which can be described as well-designed are of interest in practical equipment design. A prediction procedure is provided for well-designed slots which describes growth of the film downstream of the first of the three film regions. Comparisons of predictions with measured data are made for several very different well-designed slots over a relatively wide range of injection conditions, and good agreement is shown.

Enhancement of Full Coverage Film Cooling Effectiveness with Mixed Injection Holes

International Journal of Turbo and Jet Engines ◽

10.1515/tjj-2018-0025 ◽

2018 ◽

Vol 0 (0) ◽

Author(s):

Mukesh Prakash Mishra ◽

A K Sahani ◽

Sunil Chandel ◽

R K Mishra

Keyword(s):

Film Cooling ◽

Numerical Study ◽

Velocity Ratio ◽

Perforated Plate ◽

Combustion Chambers ◽

Cooling Effectiveness ◽

Full Coverage ◽

Upstream Direction ◽

The Difference

Abstract In the present work numerical study of full coverage film cooling on an adiabatic flat plate is carried out. Cooling performance of three configurations of cylindrical holes is studied with downstream injection, upstream injection and mixed injection. In mixed injection configuration one column of holes inject in downstream direction and the holes in the adjacent column inject in the upstream direction. Numerical simulations are carried out at different velocity ratios and circumferentially averaged value of adiabatic film cooling effectiveness is estimated. Simulation results indicate that the mixed injection configuration has better and more uniform cooling, throughout the perforated plate, than with downstream injection. The difference is greater with increase in the velocity ratio. Configuration with upstream injection gives better cooling than mixed injection at front few rows of cooling holes but it shows poorer performance with downstream injection in the downstream rows of cooling holes. The obtained results from this study can be an invaluable input for highly loaded combustion chambers.

Leading Edge Film Cooling of a Turbine Blade Model Through Single and Double Row Injection: Effects of Coolant Density

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration ◽

10.1115/94-gt-002 ◽

1994 ◽

Cited By ~ 8

Author(s):

M. Salcudean ◽

I. Gartshore ◽

K. Zhang ◽

Y. Barnea

Keyword(s):

Turbine Blade ◽

Mass Flow ◽

Film Cooling ◽

Leading Edge ◽

Spanwise Direction ◽

Double Row ◽

Cooling Effectiveness ◽

Stagnation Line ◽

Staggered Arrangement

Experiments have been conducted on a large model of a turbine blade. Attention has been focussed on the leading edge region, which has a semi-circular shape and four rows of film cooling holes positioned symmetrically about the stagnation line. The cooling holes were oriented in a spanwise direction with an inclination of 30° to the surface, and had streamwise locations of ±15° and ±44° from the stagnation line. Film cooling effectiveness was measured using a heat/mass analogy. Single row cooling from the holes at 15° and 44° showed similar patterns: spanwise averaged effectiveness which rises from zero at zero coolant mass flow to a maximum value η* at some value of mass flow ratio M*, then drops to low values of η at higher M. The trends can be quantitatively explained from simple momentum considerations for either air or CO2 as the coolant gas. Close to the holes, air provides higher η values for small M. At higher M, particularly farther downstream, the CO2 may be superior. The use of an appropriately defined momentum ratio G collapses the data from both holes using either CO2 or air as coolant onto a single curve. For η*, the value of G for all data is about 0.1. Double row cooling with air as coolant shows that the relative stagger of the two rows is an important parameter. Holes in line with each other in successive rows can provide improvements in spanwise averaged film cooling effectiveness of as much as 100% over the common staggered arrangement. This improvement is due to the interaction between coolant from rows one and two, which tends to provide complete coverage of the downstream surface when the rows are placed correctly with respect to each other.

Effects of Inlet Swirl on Pressure Side Film Cooling of Neighboring Vane Surface

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4043260 ◽

2019 ◽

Vol 11 (6) ◽

Cited By ~ 3

Author(s):

Yang Zhang ◽

Yifei Li ◽

Xiutao Bian ◽

Xin Yuan

Keyword(s):

Film Cooling ◽

Swirling Flow ◽

Density Ratio ◽

Suction Side ◽

Scale Model ◽

Cooling Effectiveness ◽

Lean Combustion ◽

Inlet Swirl ◽

Nozzle Guide

The lean combustion chamber of low NOx emission engines has a short distance between combustion outlet and nozzle guide vanes (NGVs), with strong swirlers located upstream of the turbine inlet to from steady circulation in the combustion region. Although the lean combustion design benefits emission control, it complicates the turbine’s aerodynamics and heat transfer. The strong swirling flow will influence the near-wall flow field where film cooling acts. This research investigates the influence of inlet swirl on the film cooling of cascades. The test cascades are a 1.95 scale model based on the GE-E3 profile, with an inlet Mach number of 0.1 and Reynolds number of 1.48 × 105. Film cooling effectiveness is measured with pressure-sensitive paint (PSP) technology, with nitrogen simulating coolant at a density ratio of near to 1.0. Two neighboring passages are investigated simultaneously, so that pressure and suction side the film cooling effectiveness can be compared. The inlet swirl is produced by a swirler placed upstream, near the inlet, with five positions along the pitchwise direction. These are as follows: blade 1 aligned, passage 1–2 aligned, blade 2 aligned, passage 2–3 aligned and blade 3 aligned. According to the experimental results, the near-hub region is strongly influenced by inlet swirl, where the averaged film cooling effectiveness can differ by up to 12% between the neighboring blades. At the spanwise location Z/Span = 0.7, when the inlet swirl is moved from blade 1 aligned (position 5) to blade 2 aligned (position 3), the film cooling effectiveness in a small area near the endwall can change by up to 100%.

Account of Film Turbulence for Predicting Film Cooling Effectiveness in Gas Turbine Combustors

Journal of Engineering for Power ◽

10.1115/1.3230295 ◽

1980 ◽

Vol 102 (3) ◽

pp. 524-534 ◽

Cited By ~ 7

Author(s):

G. J. Sturgess

Keyword(s):

Gas Turbine ◽

Film Cooling ◽

Cooling Effectiveness ◽

Turbine Engine ◽

Wide Range ◽

Engine Combustion ◽

Turbulence Effects ◽

The Impact ◽

Development of a 1300.DEG.C.-class gas turbine combustor burning coal-derined low BTU gaseous fuels. 2nd Report, Low NOx combustion technology by rich-lean combustion.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.56.3903 ◽

1990 ◽

Vol 56 (532) ◽

pp. 3903-3909 ◽

Author(s):

Mikio SATO ◽

Toru NINOMIYA ◽

Toshio ABE ◽

Toshiyuki YOSHINE ◽

Hiroshi HASEGAWA

Keyword(s):

Gas Turbine ◽

Gas Turbine Combustor ◽

Gaseous Fuels ◽

Lean Combustion ◽

Combustion Technology ◽

Low Nox Combustion ◽

Burning Coal

Film Cooling Effectiveness From Two Rows of Compound Angled Cylindrical Holes Using Pressure-Sensitive Paint Technique

Journal of Heat Transfer ◽

10.1115/1.4042777 ◽

2019 ◽

Vol 141 (4) ◽

Author(s):

Nian Wang ◽

Mingjie Zhang ◽

Chao-Cheng Shiau ◽

Je-Chin Han

Keyword(s):

Flat Plate ◽

Film Cooling ◽

Density Ratio ◽

Pressure Sensitive Paint ◽

Cooling Effectiveness ◽

Blowing Ratio ◽

Pressure Sensitive ◽

Staggered Arrangement ◽

Cylindrical Holes

This study investigates the effects of blowing ratio, density ratio, and spanwise pitch on the flat plate film cooling from two rows of compound angled cylindrical holes. Two arrangements of two-row compound angled cylindrical holes are tested: (a) the first row and the second row are oriented in staggered and same compound angled direction (β = +45 deg for the first row and +45 deg for the second row); (b) the first row and the second row are oriented in inline and opposite direction (β = +45 deg for the first row and −45 deg for the second row). The cooling hole is 4 mm in diameter with an inclined angle of 30 deg. The streamwise row-to-row spacing is fixed at 3d, and the spanwise hole-to-hole (p) is varying from 4d, 6d to 8d for both designs. The film cooling effectiveness measurements were performed in a low-speed wind tunnel in which the turbulence intensity is kept at 6%. There are 36 cases for each design including four blowing ratios (M = 0.5, 1.0, 1.5, and 2.0), three density ratios (DR = 1.0, 1.5, and 2.0), and three hole-to-hole spacing (p/d = 4, 6, and 8). The detailed film cooling effectiveness distributions were obtained by using the steady-state pressure-sensitive paint (PSP) technique. The spanwise-averaged cooling effectiveness are compared over the range of flow parameters. Some interesting observations are discovered including blowing ratio effect strongly depending on geometric design; staggered arrangement of the hole with same orientation does not yield better effectiveness at higher blowing ratio. Currently, film cooling effectiveness correlation of two-row compound angled cylindrical holes is not available, so this study developed the correlations for the inline arrangement of holes with opposing angles and the staggered arrangement of holes with same angles. The results and correlations are expected to provide useful information for the two-row flat plate film cooling analysis.

Experimental Study on Analogy Principle of Overall Cooling Effectiveness for Composite Cooling Structures With Both Internal Cooling and Film Cooling

Volume 5A: Heat Transfer ◽

10.1115/gt2019-90705 ◽

2019 ◽

Author(s):

Gang Xie ◽

Cun-liang Liu ◽

Rui Wang ◽

Lin Ye ◽

Jiajia Niu

Keyword(s):

Film Cooling ◽

Momentum Flux ◽

Flux Ratio ◽

Theoretical Work ◽

Maximum Deviation ◽

Internal Cooling ◽

Cooling Effectiveness ◽

Impingement Cooling ◽

Staggered Arrangement ◽

Cooling Model

Abstract The previous theoretical work showed the matching principles of analogy parameters for effusion-impingement cooling model. The mismatch of temperature ratios Tg/Tc may result in different matching performance in laboratory condition. Thus, the analogy principles of overall cooling effectiveness were evaluated by experiments in different laboratory conditions for effusion-impingement cooling model. The film plate had 8 rows of cylinder film holes with staggered arrangement and the impingement holes was also employed staggered pattern. Four kinds of cases with different temperature ratios, varied from 1.1 to 2, were tested under three momentum flux ratios and corresponding blowing ratios. The 2D contours of overall cooling effectiveness were measured by using IR thermography. The results for cases with the same mainstream side Biot number and momentum flux ratio show similar contours and values of overall cooling effectiveness, although temperature ratios of these cases are different. And the maximum deviation of overall cooling effectiveness is within 0.02 for these cases. However, there were 0.04∼0.08 difference in the overall cooling effectiveness when the blowing ratios were matched. The overall cooling effectiveness significantly decreases under each blowing ratios with the increase of temperature ratios.