Investigation of Velocity Profiles for Effusion Cooling of a Combustor Liner

Scrittore, J. J.; Thole, Karen A.; Burd, Steven W.

doi:10.1115/gt2006-90532

Cited by 21 publications

(9 citation statements)

References 15 publications

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“…For a single-walled effusion liner without dilution jets, Scrittore et al [10] found that the velocity profiles and turbulence levels of the effusion jets scaled with the blowing ratio of the effusion jets. In addition, they found that once the flow was fully developed, the momentum flux ratio of the effusion jets did not affect the penetration height.…”

Section: Relevant Past Studiesmentioning

confidence: 99%

Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner: Part 2 — Flowfield Measurements

Shrager

Thole

Mongillo

2018

Volume 5C: Heat Transfer

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The complex flowfield inside a gas turbine combustor creates a difficult challenge in cooling the combustor walls. Many modern combustors are designed with a double-wall that contain both impingement cooling on the backside of the wall and effusion cooling on the external side of the wall. Complicating matters is the fact that these double-walls also contain large dilution holes whereby the cooling film from the effusion holes is interrupted by the high-momentum dilution jets. Given the importance of cooling the entire panel, including the metal surrounding the dilution holes, the focus of this paper is understanding the flow in the region near the dilution holes. Near-wall flowfield measurements are presented for three different effusion cooling hole patterns near the dilution hole. The effusion cooling hole patterns were varied in the region near the dilution hole and include: no effusion holes; effusion holes pointed radially outward from the dilution hole; and effusion holes pointed radially inward toward the dilution hole. Particle image velocimetry (PIV) was used to capture the time-averaged flowfield at approaching freestream turbulence intensities of 0.5% and 13%. Results showed evidence of downward motion at the leading edge of the dilution hole for all three effusion hole patterns. In comparing the three geometries, the outward effusion holes showed significantly higher velocities toward the leading edge of the dilution jet relative to the other two geometries. Although the flowfield generated by the dilution jet dominated the flow downstream, each cooling hole pattern interacted with the flowfield uniquely. Approaching freestream turbulence did not have a significant effect on the flowfield.

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Section: Relevant Past Studiesmentioning

confidence: 99%

Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner: Part 2 — Flowfield Measurements

Shrager

Thole

Mongillo

2018

Volume 5C: Heat Transfer

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“…Conceming the investigation of combustor typical effusion cooling schemes, Scrittore et al [7,8] conducted studies on velocity profiles along an effusion cooled liner and about the effect of combustor typical features like dilution jets on the cooling effectiveness. These studies show that the streamwise velocity and turbulence level directly scale with the blowing ratio and that a full-coverage effusion cooling develops into a fully-developed velocity profile at a nominal location of 15 film-cooling hole rows downstream.…”

Section: Related Past Investigationsmentioning

confidence: 99%

Impact of Swirl Flow on the Cooling Performance of an Effusion Cooled Combustor Liner

Wurm¹,

Schulz²,

Bauer

et al. 2012

Journal of Engineering for Gas Turbines and Power

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An experimental study on combustor liner cooling of modern direct lean injection combustion chambers using coolant ejection from both effusion cooling holes and a starter film has been conducted. The experimental setup consists of a generic scaled three sector planar rig in an open loop hot gas wind tunnel, which has been described earlier in Wurm et al. (2009, “A New Test Facility for Investigating the Interactions Between Swirl Flow and Wall Cooling Films in Combustors, Investigating the Interactions Between Swirl Flow and Wall Cooling Films in Combustors,” ASME Paper No. GT2009-59961). Experiments are performed without combustion. Realistic engine conditions are achieved by applying engine-realistic Reynolds numbers, Mach numbers, and density ratios. A particle image velocimetry (PIV) measurement technique is employed, which has been adjusted to allow for high resolution near wall velocity measurements with and without coolant ejection. As the main focus of the present study is a deeper understanding of the interaction of swirl flows and near wall cooling flows, wall pressure measurements are performed for the definition of local blowing ratios and to identify the impact on the local cooling performance. For thermal investigations an infrared thermography measurement technique is employed that allows high resolution thermal studies on the effusion cooled liner surface. The effects of different heat shield geometry on the flow field and performance of the cooling films are investigated in terms of near wall velocity distributions and film cooling effectiveness. Two different heat shield configurations are investigated which differ in shape and inclination angle of the so called heat shield lip. Operating conditions for the hot gas main flow are kept constant. The pressure drop across the effusion cooled liner is varied between 1% and 3% of the total pressure. Results show the impact of the swirled main flow on the stability of the starter film and on the effusion cooling performance. Stagnation areas which could be identified by wall pressure measurements are confirmed by PIV measurements. Thermal investigations reveal reduced cooling performance in the respective stagnation areas.

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“…An interesting attempt to characterize the effects of the swirled flow on combustor heat transfer is conducted by Patil et al [11] which, studying an air spray nozzle with a swirl number of 0.7, pointed out how increasing Reynolds number does not change the position of the peak in heat flux due to the impingement of the swirl flow on the liner, whereas the intensity of the peak is reduced. However, as already mentioned, most studies devoted to effusion cooling deal with flat plates which have been quite exten sively studied both singularly and with additional cooling features such as impingement jets [12,13], slot cooling [14], and dilution holes [15,16]. Focusing on effusion systems only, Behrendt et al [4] showed that shallow angles promote cooling effectiveness due to reduced jet penetration and increased heat removal within the perforations.…”

Section: Introductionmentioning

confidence: 98%

Investigation on the Effect of a Realistic Flow Field on the Adiabatic Effectiveness of an Effusion-Cooled Combustor

Andrei

Andreini

Bianchini

et al. 2015

Journal of Engineering for Gas Turbines and Power

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Effusion cooling represents the state of the art of liner cooling technology for modern combustors. This technique consists of an array of closely spaced discrete film cooling holes and contributes to lower the metal temperature by the combined protective effect of coolant film and heat removal through forced convection inside each hole. Despite many efforts reported in literature to characterize the cooling performance of these devices, detailed analyses of the mixing process between coolant and hot gas are difficult to per form, especially when superposition and density ratio effects as well as the interaction with complex gas side flow field become significant. Furthermore, recent investigations on the acoustic properties of these perforations pointed out the challenge to maintain optimal cooling performance also with orthogonal holes, which showed higher sound absorption. The objective of this paper is to investigate the impact of a realistic flow field on the adiabatic effectiveness performance of effusion cooling liners to verify the findings available in literature, which are mostly based on effusion flat plates with aligned cross flow, in case of swirled hot gas flow. The geometry consists of a tubular combustion chamber, equipped with a double swirler injection system and characterized by 22 rows of cooling holes on the liner. The liner cooling system employs slot cooling as well: its interactions with the cold gas injected through the effusion plate are investigated too. Taking advantage of the rotational periodicity of the effusion geometry and assuming axisymmetric conditions at the combustor inlet, steady state RANS calculations have been performed with the commercial code ansys® CFX simulating a single circumferential pitch. Obtained results show how the effusion perforation angle deeply affects the flowfield around the corner of the combustor, in particular, with a strong reduction of slot effectiveness in case o f 90deg angle value.

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Investigation of Velocity Profiles for Effusion Cooling of a Combustor Liner

Cited by 21 publications

References 15 publications

Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner: Part 2 — Flowfield Measurements

Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner: Part 2 — Flowfield Measurements

Impact of Swirl Flow on the Cooling Performance of an Effusion Cooled Combustor Liner

Investigation on the Effect of a Realistic Flow Field on the Adiabatic Effectiveness of an Effusion-Cooled Combustor

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