Evolution of jets effusing from inclined holes into crossflow

Jessen, Wilhelm; Schröder, Wolfgang; Klaas, Michael

doi:10.1016/j.ijheatfluidflow.2007.06.010

Cited by 28 publications

(9 citation statements)

References 15 publications

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“…The flow is fully detached if the IR is higher than 0.8. Jessen et al [7] reported that a higher velocity ratio (VR) enlarges the size of the recirculation region leading to a more pronounced entrainment of crossflow fluid into the wake of the jet. Velocity effects dominate the flow field in the vicinity of the jet hole.…”

Section: Review Of Past Researchmentioning

confidence: 99%

“…The DR alone cannot determine the effectiveness and the primary factor influencing the film effectiveness is claimed to be the IR instead. Nevertheless, Jessen et al [7] found that the lateral spreading of the coolant downstream, which is crucial for the cooling efficiency, is strongly increased by increasing the DR.…”

Section: Review Of Past Researchmentioning

confidence: 99%

“…Based on an extensive literature survey, the experimental and simulation studies of Jessen et al [7] of single-hole cooling is chosen as the benchmark for verification. They investigated the turbulent flow structure and vortex dynamics of a jet-in-a-cross flow problem that is directly related to gas turbine blade film cooling.…”

Section: Modeling Approach and Verificationmentioning

confidence: 99%

“…They investigated the turbulent flow structure and vortex dynamics of a jet-in-a-cross flow problem that is directly related to gas turbine blade film cooling. Jessen et al [7] experimentally studied the problem using particle-image velocimetry (PIV) technique, as well as numerically using the Large Eddy Simulation (LES) turbulence model. A cooling jet emanating from a pipe interacted with a turbulent flat plate boundary layer at a Reynolds number (Re) of 400,000.…”

Section: Modeling Approach and Verificationmentioning

confidence: 99%

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The Effects of Coolant Pipe Geometry and Flow Conditions on Turbine Blade Film Cooling

Akbar¹

2017

Journal of Thermal Engineering

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The performance of gas turbine engines can be improved by increasing the inlet gas temperature. Turbine blades can be damaged by high gas temperature, unless additional cooling mechanisms are incorporated to maintain the blades below an acceptable temperature limit. Film cooling techniques are often used to cool the blades to avoid damages. The performance of film cooling depends on several parameters, however. In this paper past research on film cooling is reviewed and areas in need of further investigation are identified. Computational fluid dynamics (CFD) simulations are then conducted on the widely-used single-hole film cooling arrangements in which coolant jets are injected into air flows inside a straight channel before issuing onto the blades. Cooling pipe-blade configurations and flow conditions are varied and the resulting flow hydrodynamics are examined. Counter rotating vortex pairs (CRVPs) formed in the flow strongly influence the film cooling performance. Small coolant inclination angles, exit holes enlargement in span wise direction, higher injected fluid density, and higher injectedambient fluid velocity ratios are all found to maintain the CRVPs away from each other and close to wall -both of which promote cooling. Pipe curvature can be used for enhancing cooling by exploiting the centrifugal force effect.

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Section: Review Of Past Researchmentioning

confidence: 99%

Section: Review Of Past Researchmentioning

confidence: 99%

Section: Modeling Approach and Verificationmentioning

confidence: 99%

Section: Modeling Approach and Verificationmentioning

confidence: 99%

See 2 more Smart Citations

The Effects of Coolant Pipe Geometry and Flow Conditions on Turbine Blade Film Cooling

Akbar¹

2017

Journal of Thermal Engineering

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“…The cooling performance was determined in terms of the induced recirculation bubble. Jessen et al (2007) assessed this cooling performance experimentally by means of particle image velocimetry (PIV) measurements, in terms of the developed turbulent flow structures and vortex dynamics, under variable injection, density, and mass fraction ratios. A higher mass flux ratio enlarges the size of the recirculation region, leading to a more pronounced entrainment of hot outer fluid into the wake of the jet and a higher density ratio enhances the lateral spreading of the coolant downstream, which is crucial for the cooling efficiency.…”

Section: Introductionmentioning

confidence: 99%

The Near Field in the Mixing of a Three-Dimensional Inclined Pollutant Jet With a Crossflow

Mahjoub¹,

Habli

Bournot

et al. 2012

J Enh Heat Transf

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An experimental investigation was carried out to study the structure of the flow field resulting from the interaction of an inclined pollutant jet with a crossflow. The study of the flow field was conducted in a wind tunnel test by means of particle image velocimetry (PIV) system. As the jet was discharged with a variable angle, the resulting flow has been found to be quite complex owing to its three-dimensional nature and the interaction between several flow regions. Results showed the dependence of the emerging jet flow structure on its ratio velocity and the Reynolds number. Extensive wind tunnel experimental results are presented; they concern the Kelvin-Helmholtz vortical structures and the effect of the velocity ratio v0/u∞ on the interacting zone. A three-dimensional numerical model with a second-order turbulent model (RSM) and a nonuniform grid system is used to examine the behavior of the emerging jet. The comparison of the numerical and experimental results gives satisfactory agreement.

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