Heat Transfer Technology for Internal Passages of Air‐Cooled Blades for Heavy‐Duty Gas Turbines

Semmler, Klaus; Wolfersdorf, Jens von

doi:10.1111/j.1749-6632.2001.tb05851.x

Cited by 28 publications

(6 citation statements)

References 72 publications

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“…2, there is a strong dependency on the downstream position in the driving fluid temperature T f and consequently the defined dimensionless temperature ratio Θ w does not reflect the real behavior far downstream using Eqn. (2). In order to avoid an excessive instrumentation of the model while considering local dimensionless temperature ratios, a data reduction procedure was suggested by von Wolfersdorf et al [4].…”

Section: Data Analysis Modelmentioning

confidence: 99%

“…Nowadays complex multipass systems using several cooling methods in combination are widely used. Since such systems are often developed by combining results achieved from simplified single-pass experiments, there is a high demand for understanding such a system altogether [1][2][3]. Full cooling circuits of a blade differ from their single-pass predecessors mainly in geometrical complexity.…”

Section: Introductionmentioning

confidence: 99%

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Transient Heat Transfer Experiments in Complex Passages

Poser

Wolfersdorf

Semmler

2005

Heat Transfer: Volume 1

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Transient heat transfer experiments were performed in a model of a multi-pass gas turbine blade cooling circuit. The inner surface of the Plexiglas model was coated with thermochromic liquid crystals in order to determine the internal heat transfer coefficients. A change in inlet temperature is applied using a precooled heat exchanger. As for simple geometries the analytical solution of Fourier's equation can often be directly used for data evaluation, one ought to pay attention to complex passages. The reason has to be seen that the flow in complex passages has to be characterized by local and time dependent fluid temperatures. As a direct consequence data evaluation might be limited to small evaluation areas especially far downstream. Otherwise the uncertainties in the heat transfer results will increase substantially. In the present study the sensitivity of the transient method for complex passages has been analyzed theoretically and applied experimentally.1

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Section: Data Analysis Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transient Heat Transfer Experiments in Complex Passages

Poser

Wolfersdorf

Semmler

2005

Heat Transfer: Volume 1

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“…Due to these high thermal loads, an efficient and reliable turbine blade cooling is necessary. Ligrani et al (2003) and Weigand et al (2001) reviewed different internal cooling techniques like ribs, turbulators, impingement cooling and swirl chambers to enhance the convective heat transfer in cooling passages. Swirl chambers are least investigated from the above given cooling methods and the subject of this paper.…”

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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“…Compared to the heat transfer requirements for aero-engine blades, the cooling schemes of blades for large industrial gas turbines differ in some aspects (see e.g. Weigand et al [12]). An important difference is that blades for heavy-duty gas turbines are subjected to much higher Reynolds numbers in the internal cooling passages mainly due to their much larger dimensions.…”

Section: Introductionmentioning

confidence: 99%