Flow of cooling air in an electric generator model – An experimental and numerical study

Moradnia, Pirooz; Golubev, Maxim; Chernoray, Valery; Nilsson, Håkan

doi:10.1016/j.apenergy.2013.10.033

Cited by 27 publications

(12 citation statements)

References 3 publications

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“…Figure 1 shows the general appearance of a vacuum pump unit (VALUE, Delhi, India), which included the tested single-phase electric motor whose speed is controlled by a frequency inverter. the results can be carried out by using experimental data [7]. In general, after validation, the accuracy of the obtained results can be considered as satisfied when the complexity of the geometrical model is taken into account [8].…”

Section: Methodsmentioning

confidence: 99%

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Investigation of Heat Loss from the Finned Housing of the Electric Motor of a Vacuum Pump

Wernik

2017

Applied Sciences

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Investigation of the heat transfer by conduction and convection through a finned housing of an electric motor rated 373 W operated in the drive unit of a vacuum pump was carried out. As the speed is changed, so is the velocity of air flow, and consequently, the coefficient of heat transfer across the housing surface is changed too. To predict the values of the average heat transfer coefficient and to determine the heat flow that was dissipated at variable motor speed is a complex task, for which no reliable tools can be found in the literature. Using finite element approximation, the heat transfer was numerically simulated and the temperature distribution on the housing surface was determined. In order to validate the simulation model, an experimental set-up was assembled, including the vacuum pump complete with its driving unit, that is, electrical motor and frequency converter, and FLIR SC7600 thermovision camera. Using the validated simulation model, the heat flux transferred through the housing to the environment and the share of heat dissipation in the power consumed by the vacuum pump drive was determined. The combination of numerical simulation and thermographic measurements is an effective tool.

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Section: Methodsmentioning

confidence: 99%

“…Examples of application of the FEM in the field of heat exchange can be found in [5,6]. Validation of the results can be carried out by using experimental data [7]. In general, after validation, the accuracy of the obtained results can be considered as satisfied when the complexity of the geometrical model is taken into account [8].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Heat Loss from the Finned Housing of the Electric Motor of a Vacuum Pump

Wernik

2017

Applied Sciences

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“…The geometry used in the present work is based on the electric generator model studied by Moradnia et al [11]. This generator model has a rotor with 12 poles, a fan attached on top of the rotor, 4 rows of stator cooling channels along the axis of rotation, see Fig.…”

Section: Generator Model Specificationsmentioning

confidence: 99%

“…They mentioned that a rational design of the stator duct entrances can both reduce the pressure loss of the stator ventilation, and improve the cooling in the stator ducts. Moradnia et al [11][12][13] performed steady-state frozen rotor simulations of a simplified electric generator and validated the results with experimental measurements. They developed a fully predictive simulation method for a hydro-generator model.…”

Section: Introductionmentioning

confidence: 99%

“…Overall, the heat transfer at the end windings or the flow field inside the stator ducts can barely be computed using thermal networks, while the application of three-dimensional numerical methods makes these predictions possible. CFD offers a good potential to fully predict ventilation and cooling in generators [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. CFD has the advantage that it can be used to predict the flow and heat transfer in complex regions, without case-specific empirical correlations.…”

Section: Introductionmentioning

confidence: 99%

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CFD-based Design and Analysis of the Ventilation of an Electric Generator Model, Validated with Experiments

Jamshidi

Nilsson

Chernoray

2015

International Journal of Fluid Machinery and Systems

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The efficiency of the ventilation system is a key point for durable and reliable electric generators. The design of such system requires a detailed understanding of the air flow in the generator. Computational fluid dynamics (CFD) has the potential to resolve the lack of information in this field. The present work analyses the air flow inside a generator model. The model is designed using a CFD-based approach, and manufactured by taking into consideration the experimental and numerical requirements and limitations. The emphasis is on the possibility to accurately predict and experimentally measure the flow distribution inside the stator channels. A major part of the work is focused on the design of an intake and a fan that gives an evenly distributed flow with a high flow rate. The intake also serves as an accurate flowmeter. Experimental results are presented, of the total volume flow rate, the total pressure and velocity distributions. Steadystate CFD simulations are performed using the FOAM-extend CFD toolbox. The simulations are based on the multiple rotating reference frames method. The results from the frozen rotor and mixing plane rotor-stator coupling approaches are compared. It is shown that the fan design provides a sufficient flow rate for the stator channels, which is not the case without the fan or with a previous fan design. The detailed experimental and numerical results show an excellent agreement, proving that the results reliable.

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Assessment of the naphthalene sublimation technique for determination of convective heat transfer in fundamental and industrial applications

et al. 2019

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The naphthalene sublimation technique is an experimental method for indirectly determining convective heat transfer. The technique is here assessed for two different configurations: the local heat transfer distribution for a circular air jet impinging normal to a flat surface, and the heat transfer occurring in the stator core of an electric generator model. The turbulent impinging jet is fully developed. Two Reynolds numbers based on the nozzle exit condition, 15000 and 23000, and two nozzle diameter distances from the jet exit to the surface, 6 and 8, are considered. For the generator turbulent internal flow with Reynolds number of 4100 is considered, based on the hydraulic diameter of stator ventilation ducts. Modern surface scanning methods and imprints of the naphthalene specimens were used for measuring the naphthalene sublimation rate. The impinging jet results are compared with experimental data found in the literature. Results from the generator model and numerical simulations are compared. For the impinging jet, the results show agreement with the already published experimental data sets. For the generator model, heat transfer results from experiments differ by around 13% compared to numerical results if a scanning of the surface is used for measuring the naphthalene sublimation and around 5% if weights are used for measuring the sublimation rate. Therefore, the results depend on the way the sublimation rate is quantified. From this study, it is possible to affirm that with advanced scanning procedures, the heat transfer can be resolved with very small naphthalene sublimation in cases of both fundamental and complex industrial applications such as electric generators. NomenclatureSc Schmidt number. Pr Prandtl number. d Inner diameter of the nozzle, m. d h Hydraulic diameter, m. U Bulk velocity, m/s. ν Kinematic viscosity, m 2 /s. Re Reynolds number, Ud/ν. Re dh Reynolds number based on hydraulic diameter, Ud h /ν. H Nozzle exit to plate distance, m. Z Normal coordinate, m.

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Flow of cooling air in an electric generator model – An experimental and numerical study

Cited by 27 publications

References 3 publications

Investigation of Heat Loss from the Finned Housing of the Electric Motor of a Vacuum Pump

Investigation of Heat Loss from the Finned Housing of the Electric Motor of a Vacuum Pump

CFD-based Design and Analysis of the Ventilation of an Electric Generator Model, Validated with Experiments

Assessment of the naphthalene sublimation technique for determination of convective heat transfer in fundamental and industrial applications

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