Convective heat transfer in the entry region of an annular channel with slotted rotating inner cylinder

Fénot, Matthieu; Dorignac, Eva; Giret, Antoine; Lalizel, Gildas

doi:10.1016/j.applthermaleng.2012.10.039

Cited by 37 publications

(13 citation statements)

References 26 publications

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“…However, their measurements show again a similar behaviour of the heat transfer rate with a sudden increase at T a m ≈ 3 × 10 3 . More recently the heat transfer in an annulus between coaxial cylinders with slots had been studied [13], [30], [14]. However, these works analyse a Taylor-Couette-Poiseuille flow, meaning that an axial air flux is superimposed across the Taylor-Couette flow generated by the rotation of the internal or external cylinder.…”

Section: Literature Reviewmentioning

confidence: 99%

Air-gap convection in a switched reluctance machine

Romanazzi

Howey

2015

2015 Tenth International Conference on Ecological Vehicles and Renewable Energies (EVER)

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Switched reluctance machines (SRMs) have recently become popular in the automotive market as they are a good alternative to the permanent magnet machines commonly employed for an electric powertrain. Lumped parameter thermal networks are usually used for thermal analysis of motors due to their low computational cost and relatively accurate results. A critical aspect to be modelled is the rotor-stator air-gap heat transfer, and this is particularly challenging in an SRM due to the salient pole geometry. This work presents firstly a review of the literature including the most relevant correlations for this geometry, and secondly, numerical CFD simulations of air-gap heat transfer for a typical configuration. A new correlation has been derived: Nu = 0.181 Ta 0.207 m . This paper is part of the ADvanced Electric Powertrain Technology (ADEPT) project which is an EU funded Marie Curie ITN project, grant number 607361. Within ADEPT a virtual and hardware tool are created to assist the design and analysis of future electric propulsion, especially within the context of the paradigm shift from fuel powered combustion engines to alternative energy sources (e.g. fuel cells, solar cells, and batteries) in vehicles like motorbikes, cars, trucks, boats, planes. The design of these high performance, low cost and clean propulsion systems has stipulated an international cooperation of multiple disciplines such as physics, mathematics, electrical engineering, mechanical engineering and specialisms like control engineering and safety. By cooperation of these disciplines in a structured way, the ADEPT program provides a virtual research lab community from labs of European universities and industries [1].

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Section: Literature Reviewmentioning

confidence: 99%

Air-gap convection in a switched reluctance machine

Romanazzi

Howey

2015

2015 Tenth International Conference on Ecological Vehicles and Renewable Energies (EVER)

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“…More recently the heat transfer in an annulus between coaxial cylinders with slots had been studied [24][25][26]. Fénot et al [27] were interested in convective exchanges in the gap in the case where only the rotor is grooved (4 slots). They did their studies on an open synchronous motor with 4 poles; the authors studied the influence of the air flow on the convective transfer and they noticed thus, that it is dependent on the speed of axial rotation and that of the rotor.…”

Section: Introductionmentioning

confidence: 99%

Impact of the grooves on the enhancement of heat transfer in an annular space of a rotor-stator

Attou¹,

Zineddine²,

Meghdir³

2018

IJHT

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This work concerns a numerical study of heat transfer by convection in an annulocylindrical space of an axial air flow between a rotor rotating at constant angular velocity and a fixed stator. We used the Fluent software to simulate the thermal influence on the groove. We propose to study four geometric configurations of the rotor and stator. The first is to take the surfaces of the rotor and the stator as smooth. In the second configuration, the stator wall is grooved along the cylinder and the rotor is smooth. For the third, it is considered that the rotor and the stator are provided with grooves of the same geometrical shape as regards the last case; it is only on the rotor that the same types of grooves are considered. The numerical results obtained in rotational flow for different rotational speeds of the rotor and for different air injection rates through grooves of different depth values have shown that the presence of grooves enhances the heat transfer at as speed increases. In the presence of an axial flow of air, the results obtained in a turbulent flow show that the case of the grooved rotor is interesting from the thermal point of view with respect to the others (smooth, grooved stator, and grooved rotor-stator). This numerical study is based on the use of an SST (Shear-Stress-Transport) type turbulence model to evaluate heat exchanges in the various rotor-stator configurations.

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“…They indicated that the heat transfer level on the endwall was well predicted before the two legs of the horseshoe vortex system meeting, but the code under-predicted the influence of the corner vortex and over-predicted the heat transfer level associated with the cross-flow. Fe´not et al 12 experimentally studied the convective heat transfer characteristic in the entry region of an annular channel with a slotted rotating inner cylinder. The results confirmed the importance of axial ratio and inlet velocity profile on the heat transfer performance.…”

Section: Introductionmentioning

confidence: 99%

“…Fénot et al. 12 experimentally studied the convective heat transfer characteristic in the entry region of an annular channel with a slotted rotating inner cylinder. The results confirmed the importance of axial ratio and inlet velocity profile on the heat transfer performance.…”

Section: Introductionmentioning

confidence: 99%

Effects of tip cavity geometries on the aerothermal performance of the transonic turbine blade with cavity tip

Song

2016

Proceedings of the Institution of Mechanical Engineers, Part A:

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The inevitable transonic tip leakage flow in unshrouded high pressure gas turbines induces aerodynamic loss and gives rise to heavy thermal loads on the blade tip. In the pursuit of superior gas turbine engine, cavity tips are widely used in high-pressure turbines to reduce the over-tip leakage flow. The present research aims to numerically investigate the influence of the depth of cavity and thickness of squealer rim on the aerothemal performance of the transonic turbine blade. Three-dimensional (3D) Reynolds-Averaged Navier-Stokes (RANS) equations with Spalart-Allmaras turbulence were solved to perform the simulation. The obtained results indicate that the variations of the cavity depth and squealer rim thickness have significant effects on the aerothermal performance of the transonic turbine blade tip regions. The phenomena in this transonic setup are different from the results obtained in subsonic condition. This study quantified that the improvement of aerodynamic efficiency contributed to the enhancement of heat flux on the blade tip in transonic condition by changing the geometry of tip cavity.

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Convective heat transfer in the entry region of an annular channel with slotted rotating inner cylinder

Cited by 37 publications

References 26 publications

Air-gap convection in a switched reluctance machine

Air-gap convection in a switched reluctance machine

Impact of the grooves on the enhancement of heat transfer in an annular space of a rotor-stator

Effects of tip cavity geometries on the aerothermal performance of the transonic turbine blade with cavity tip

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