Flow Phenomena in Swirl Chambers

Ligrani, Phillip M.; Hedlund, C. R.; Thambu, R.; Babinchak, B. T.; Moon, Hee Koo; Glezer, B.

doi:10.1115/97-gt-530

Cited by 17 publications

(8 citation statements)

References 20 publications

(13 reference statements)

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“…Based on the test [7] where air was injected tangentially, the heat transfer enhancement of vortex cooling is attributed to high axial velocity near the wall and high turbulence level. Ligrani et al [8] experimentally investigated the flow phenomena of vortex cooling passages. They captured the Görtler vortex pairs in the vortex chamber and determined their pronounced influences on heat transfer improvement.…”

Section: Introductionmentioning

confidence: 99%

Effect of jet nozzle geometry on flow and heat transfer performance of vortex cooling for gas turbine blade leading edge

et al. 2016

Applied Thermal Engineering

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Section: Introductionmentioning

confidence: 99%

Effect of jet nozzle geometry on flow and heat transfer performance of vortex cooling for gas turbine blade leading edge

et al. 2016

Applied Thermal Engineering

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“…Glezer et al, 6 Ligrani et al, 7 and Moon et al 8 investigated the advantages of induced swirl in circular channels for heat transfer enhancement. They create swirl by injecting air into the tube throughtangentialslotsalong the wall.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer in Two-Pass Turbulated Channels Connected by Holes

Ekkad

Kontrovitz

Nasir

et al. 2002

Journal of Thermophysics and Heat Transfer

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This is part of a continuing study of a new internal channel cooling design for modern gas-turbine blades. In previous studies, the enhanced cooling in the second pass of a serpentine channel was achieved by a combination of impingement and cross ow-induced swirl. A holed or slotted divider wall replaced the 180-deg U turn connecting the two legs of the serpentine channel. Flow from one coolant pass to the adjoining coolant pass was achieved through a series of straight and angled holes and a two-dimensional slot placed along the dividing wall. The focus is to enhance the heat transfer in the rst pass of the two-pass channel using traditional rib turbulators. The effect of ribs in the rst pass on the overall second pass heat transfer enhancement is compared to channels with no rib turbulators. Heat transfer distributions are compared for three channel ow Reynolds numbers ranging between 1:0 £ £ 10 4 and 5:0 £ £ 10 4 . Three different rib con gurations, 90-deg ribs, 60-deg angled forward facing toward the divider wall, and 60-deg angled backward facing away from divider wall, are studied for all Reynolds numbers and divider wall geometries. The presence of ribs in the rst pass does not only decrease the enhanced heat transfer in the second pass, but also provides higher heat transfer enhancement in the rst pass, resulting in an increase in overall heat transfer enhancement for the entire two-pass channel. Nomenclatureb = divider wall thickness D = square channel width or height D h = channel hydraulic diameter d = hole diameter f = Darcy friction factor, 21P.D h =L/=.½ N V 2 / f 0 = Darcy friction factor in all-smooth wall channel, 0:046Re ¡0:2 f N N = total channel averaged friction factor h = convective heat transfer coef cient k = thermal conductivity of test surface material k a = thermal conductivity of air L = length of each pass P m = mass-ow rate Nu = Nusselt number, hD h =k a Nu 0 = fully developed ow Nusselt number, 0:023Re 0:8 Pr 0:4 Nu = span averaged Nusselt number N N N u = area averaged Nusselt number P = pressure Pr = Prandtl number p = hole spacing Re = channel Reynolds number, ½ N V D=¹ T = temperature t = time of color change N V = average ow velocity X = axial distance from middle of turn ® = thermal diffusivity of test surface material

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“…They studied the influence of representative rotation numbers and determined the heat transfer coefficients using an axial interpolated local fluid temperature based on the inlet and outlet temperature. Ligrani et al (1998), Thambu et al (1999, Hedlund and Ligrani (2000) investigated the local flow structure and heat transfer in large-scale swirling flows in tubes at different Reynolds numbers. The heat transfer in the swirl chamber with two axial displaced tangential inlets and one radial outlet was measured using infrared thermography in conjunction with thermocouples.…”

Section: Introductionmentioning

confidence: 99%

Flow and heat transfer measurements in a swirl chamber with different outlet geometries

Biegger¹,

Weigand²

2015

Exp Fluids

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Nomenclature A Area [m 2 ] c Heat capacity [J/(kg K)] D Tube diameter [m] f Friction factor = ∆pD/(qL) h Height [m] h Heat transfer coefficient [W/(m 2 K)] I φ Angular momentum [kg m 2 /s 2 ] I z Axial momentum [kg m/s 2 ] k Turbulent kinetic energy [m 2 /s 2 ] k Thermal conductivity [W/(m K)] L Length [m] m Mass flow [kg/s] n Number of inlet ducts Nu Nusselt number = hD/k p Pressure [kg/(m s 2 )] q Dynamic pressure [kg/(m s 2 )] r Recovery factor R Tube radius [m] Re Reynolds numberGreek symbolsAbstract In technical applications, an efficient cooling is necessary for high thermal load components such as turbine blades. One potential and promising technique is a swirling tube flow in comparison with an axial flow. The additional circumferential velocity and enhanced turbulent mixing increase the heat transfer. But the complex flow field and heat transfer mechanisms are still under research. Furthermore, the reliability of a swirl chamber regarding different outlet conditions is of great interest for a robust cooling design. Therefore, we investigated the influence of a straight, a tangential and a 180 • bend outlet. To gain understanding of the flow phenomena, we measured the velocity field by means of stereo-PIV (particle image velocimetry). We experimentally studied the cooling capability measuring the heat transfer coefficients using thermochromic liquid crystals. For an accurate cooling design, we used the local adiabatic wall temperature as the correct reference temperature for calculating the heat transfer coefficients. We will show the velocity field, the pressure loss and the heat transfer results for realistic Reynolds numbers from 10,000 to 40,000 and for swirl numbers between 2.36 and 5.3. The obtained heat transfer is more than four times higher compared to an axial tube flow. Our measurements indicate that the here investigated outlet redirection has no significant influence on the flow field and the heat transfer coefficients.

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Flow Phenomena in Swirl Chambers

Cited by 17 publications

References 20 publications

Effect of jet nozzle geometry on flow and heat transfer performance of vortex cooling for gas turbine blade leading edge

Effect of jet nozzle geometry on flow and heat transfer performance of vortex cooling for gas turbine blade leading edge

Heat Transfer in Two-Pass Turbulated Channels Connected by Holes

Flow and heat transfer measurements in a swirl chamber with different outlet geometries

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