Endwall heat transfer and pressure loss measurements in staggered arrays of adiabatic pin fins

Axtmann, Meriam; Poser, Rico; Wolfersdorf, Jens von; Bouchez, Marc

doi:10.1016/j.applthermaleng.2016.04.066

Cited by 40 publications

(11 citation statements)

References 20 publications

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“…helpful in enhancement of heat transfer. Axtmann et al [1] focused their studies on thermally inactive pinfins and presented the heat transfer results in terms of Nusselt number (Nu) and also discussed about other individualities like pressure drop and thermal performance parameter of investigated configurations. Şara [2], experimentally investigated the heat transfer, pressure and performing individualities for the array of staggered square pin fins attached on a flat surface in a rectangular duct and compared it with those for the inline arrangement.…”

Section: A Parametric Thermal Analysis Of Triangular Fins For Improvementioning

confidence: 99%

A parametric thermal analysis of triangular fins for improved heat transfer in forced convection

2018

SV-JME

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Thermal management systems in electronic devices require a reduction in size due to improve the overall performance of the system. The aim is to improve the heat transfer with reduction in weight of the system. Fins are the extended surfaces that ease the heat transfer process by increasing the wetted surface area. The thermal diffusion in a fin is always affected by parameters like the size, the shape, the material, the relative arrangement, orientation and position of the fins, the working fluid and its velocity, etc. Moreover, an extended surface may affect the pressure gradient in the flow domain. In this article, a three dimensional (3D) system of aluminium fin system has been numerically modelled. Simulations are done for conjugate heat transfer problem with fins of triangular shape. The thermal analysis is performed for various input parameters viz., arrangements, orientation and the number of fins. The effect of these parameters are analysed based on Nusselt number, convective heat transfer coefficient, coefficient of friction and coefficient of pressure.

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Section: A Parametric Thermal Analysis Of Triangular Fins For Improvementioning

confidence: 99%

A parametric thermal analysis of triangular fins for improved heat transfer in forced convection

2018

SV-JME

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“…Thus, the local velocity and pressure distribution are changed and the secondary flow loss is suppressed. 16 Various nonaxisymmetric endwall modelling methods have subsequently been proposed by Germain et al, 17 Harvey et al, 18 Hartland et al, 19 Ingram et al 20 and Axtmann et al 21 ; these methods were applied to turbine guide vanes. 12,13 Moreover, the concave streamline curvature can raise the local static pressure and reduce the flow velocity.…”

Section: Introductionmentioning

confidence: 99%

“…In 1981, Kopper et al studied the effect of the nonaxisymmetric endwall on secondary flow loss control. 16 Various nonaxisymmetric endwall modelling methods have subsequently been proposed by Germain et al, 17 Harvey et al, 18 Hartland et al, 19 Ingram et al 20 and Axtmann et al 21 ; these methods were applied to turbine guide vanes. Through numerical simulation and a straight cascade blower test, a nonaxisymmetric endwall was found to have an inhibitory effect on the secondary flow loss.…”

Section: Introductionmentioning

confidence: 99%

Effect of the nonaxisymmetric endwall on wet steam condensation flow in a stator cascade

Han

et al. 2019

Energy Science & Engineering

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Steam turbines are critical pieces of power equipment in the electric power industry, and the study of wet steam condensation flow is important for improving the efficiency and safety of steam turbines. Wet steam nucleation, which is the main reason for thermodynamic losses, usually occurs downstream of the stator cascade. The mechanism of secondary flow loss control by the nonaxisymmetric endwall is the change of pressure distribution in the cascade channel. This mechanism also affects the wet steam condensation phenomenon. The positive/cosine function was proposed for endwall modification in the nucleation stage of a steam turbine. The design method presented in this paper can be used to produce endwall protrusions with different heights at different axial chords. To analyze the influence of the endwall protrusion design parameters on the condensation flow, nine endwall protrusion models were set up at varied axial positions. In comparison with the original cascade, the total pressure loss coefficient and outlet wetness were found to be ideal when the endwall protrusion maximum height was located at the 50% axial chord length of the stator and the protrusion was 3% of the blade height. The ideal incidence angle of this modified cascade was from −2° to + 10°.

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“…In addition, the wake flow shedding influences the heat transfer process in the pin-fin arrays. (a) z/H = 0 (b) z/H = 0.625 (c) z/H = 1.Turbulence levels.According to Axtmann et al[56], flow across the internal cooling passage can be characterized by pin-fin wake and horseshoe vortices. Additionally, the typical topology of flow around the pinfins array could be corner vortex, the secondary vortex, tertiary vortex and von Karman VortexStreet.…”

mentioning

confidence: 99%

Detached eddy simulation of blade trailing-edge cutback cooling performance at various ejection slot angles

Effendy

Yao

et al. 2019

International Journal of Heat and Fluid Flow

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Detached eddy simulation (DES) has been carried out to study a three-dimensional trailing-edge (TE) cutback turbine blade model with five rows of staggered circular pin-fin arrays inside the cooling passage, in order to evaluate the cooling performance in relation to coolant ejection slot angle. Simulations were performed by adopting a shear-stress transport k-ω turbulence model, and the effects of three different ejection slot angles 5°, 10° and 15° were investigated in terms of the characteristics of adiabatic film-cooling effectiveness, coefficient of discharge, and vortex shedding frequencies, respectively. The results obtained have shown that the TE cutback blade cooling with a 5° coolant ejection slot angle produced a better heat transfer coefficient than the other two ejection slot angles tested. The distributions of adiabatic film-cooling effectiveness along the cutback walls were found to be sensitive to the coolant ejection slot angle, e.g. the increase of ejection slot angle to 15 o yielded near unity of cooling effectiveness along the entire breakout walls, whereas the decrease of ejection slot angle caused a drastic decay of cooling effectiveness after the maximum effectiveness has been reached. Of the three angles studied, a TE cutback blade model with a 15° ejection slot angle produced an optimum film-cooling effectiveness. In the breakout region, vortex shedding was observed along the shear layer between the hot gas and the coolant airflow. The shedding frequencies were evaluated to be 2.93, 2.21, and 2.18 kHz for the ejection slot angles of 5°, 10° and 15°, respectively. The findings from this study

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Endwall heat transfer and pressure loss measurements in staggered arrays of adiabatic pin fins

Cited by 40 publications

References 20 publications

A parametric thermal analysis of triangular fins for improved heat transfer in forced convection

A parametric thermal analysis of triangular fins for improved heat transfer in forced convection

Effect of the nonaxisymmetric endwall on wet steam condensation flow in a stator cascade

Detached eddy simulation of blade trailing-edge cutback cooling performance at various ejection slot angles

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