Effects of Fan Blade Forward-Swept and Inclined Amounts in Electric Motors

Nakahama, T.; Ishibashi, Fuminori; Satō, Kazuo; Kawano, Kenji

doi:10.1109/tec.2010.2047042

Cited by 8 publications

(6 citation statements)

References 11 publications

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“…The axial arrangement is the most efficient, while the radial arrangement is common for small-size electric motor [41,42]. Numeric modeling has been intensively used to improve the blade profile design of the external fan in order to reduce noise and increase the cooling air speed at the motor's surface [31,55,56,59,61,89,134].…”

Section: The Air Cooling Systemmentioning

confidence: 99%

Recent Developments in Cooling Systems and Cooling Management for Electric Motors

Konovalov,

Tolstorebrov,

Eikevik

et al. 2023

Energies

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This study provides an overview of new trends in the development of cooling systems for electric motors. It includes a summary of academic research and patents for cooling systems implemented by leading motor manufacturers at TRL9. New trends in the cooling management of air and liquid cooling systems are discussed and analyzed with a focus on temperature distribution and its influence on the power-to-dimension ratio of electric motors. The prevailing cooling method for synchronous and asynchronous motors is air cooling using external fins, air circulation ducts, air gaps, and fan impellers to enhance efficiency and reliability. Internal cooling with rotor and stator ducts, along with optimized air duct geometry, shows potential to increase the power-to-dimension ratio and reduce motor size. Liquid cooling systems offer a power-to-dimension ratio of up to 25 kW/kg, achieved through redesigned cooling ducts, stator heat exchangers, and cooling tubes. However, liquid cooling systems are complex, requiring maintenance and high ingress protection ratings. They are advantageous for providing high power-to-dimension ratios in vehicles and aircraft. Discussions on using different refrigerants to improve efficient motor cooling are underway, with ozone-friendly natural refrigerants like CO2 considered to be promising alternatives to low-pressure refrigerants with high global warming potential.

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Section: The Air Cooling Systemmentioning

confidence: 99%

Recent Developments in Cooling Systems and Cooling Management for Electric Motors

Konovalov,

Tolstorebrov,

Eikevik

et al. 2023

Energies

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“…The bending of the fan characteristic curve is due to the energy losses, and can be improved by optimizing the aerodynamic structure of the blades. A new kind of axial fan with forward-swept and inclined blades is employed in [37][38][39] to reduce the ventilation resistance inside an electric motor, as is illustrated in Fig. 5.…”

Section: ) Forced Airmentioning

confidence: 99%

“…One of the major challenges associated with fan cooling is the emission of acoustic noise, especially at a high speed fan operation. Several noise mitigation methods have been proposed by the literature: a) using forward-swept inclined fans [37,38]; b) using a better aero-foil shape blade crosssection [41]; c) using inlet bell-mouth entry [42]; d) using composite materials for blades [42]; e) reducing the number of blades [41,42]; f) using irregular-pitch-blade fan [30,42,43]; g) using a mixed flow (both axial and radial) fan [41].…”

Section: ) Forced Airmentioning

confidence: 99%

“…In this paper, a detailed analysis of the active type cooling: the natural [21][22][23][24][25][26][27][28], forced air [29][30][31][32][33][34][35][36][37][38][39][40][41][42], forced liquid and phase change types [18,[66][67][68], are reviewed in Section II. On this basis, a comprehensive summary of the convection methods as applicable to the automotive traction motors cooling contexts have been provided with the advantages and disadvantages of each method being compared.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cooling of Automotive Traction Motors: Schemes, Examples, and Computation Methods

Gai

Kimiabeigi

Chong

et al. 2019

IEEE Trans. Ind. Electron.

211

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This paper presents a comprehensive overview of the latest studies and analyses of the cooling technologies and computation methods for the automotive traction motors. Various cooling methods, including the natural, forced air, forced liquid and phase change types, are discussed with the pros and cons of each method being compared. The key factors for optimizing the heat transfer efficiency of each cooling system are highlighted here. Furthermore, the real life examples of these methods, applied in the latest automotive traction motor prototypes and products, have been set out and evaluated. Finally, the analytical and numerical techniques describing the nature and performance of different cooling schemes have been explained and addressed. This paper provides guidelines for selecting the appropriate cooling methods and estimating the performance of them in the early stages of their design. Index Terms-Automotive applications, cooling, traction motors, thermal analysis, numerical analysis. NOMENCLATURECross section area of heat path (m 2 ). , Linear current density (kA/m). , Inlet and outlet cross section areas (m 2 ). Specific heat capacity (J/kg). Diameter (m). , Friction loss factor (dimensionless). Gravitational attraction force (m/s 2 ). Grashof number (dimensionless). Fin extension (m). ℎHeat transfer coefficient (W/m 2 K). ℎLatent heat (kJ/kg). Loss coefficient (dimensionless).

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“…In addition to the relative low cooling capacity of the forced convective airflow, the emission of acoustic noise from the fan was a major problem. Several attempts for mitigating the fan noise, especially at high speeds, were proposed by using the forward-swept blades [19], the aero-foil shaped blades [20], the bell-mouth fan entry, the irregular-pitch-blade fan and/or reducing the blade number [21]. With the forced convective liquid cooling schemes, the housing jackets embedded with a variety of coolant channels were commonly adopted.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer and Thermal Management of Interior Permanent Magnet Synchronous Electric Motor

Hsieh

Cai

et al. 2019

Inventions

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Geometric complexities and multi-physical phenomena add difficulties for predicting the thermal field and hence thermal management of an electric motor. A numerical design model that combined electromagnetic and thermal-fluid analysis was proposed for disclosing the detailed temperature distributions of each component in an electric motor. The thermal fluid analysis implemented ANSYS-Fluent code to unravel the thermal field of the interior permanent magnet synchronous electric motor fitted with a smooth or novel spirally twisted channel in the cooling water jacket of a stator with and without shaft cooling. In accordance with the thermal powers converted from the various electromagnetic losses of the electric motor, the complex heat conduction model with realistic thermal boundary conditions was formulated. Initially, the turbulent flow structures and channel averaged Nusselt numbers of the spiral channels without and with the sectional twist were comparatively examined for acquiring the convective thermal boundary conditions in the water jacket. With the high thermal conductivity of the aluminum water jacket, the heat-transfer improvements from the smooth-spiral-channel conditions by using the twisted spiral channel were effective for reducing the average temperatures by about 10% but less effective for altering the characteristic thermal field in the water jacket. At 1290 < Dn < 6455 or 5000 < Re < 25,000 for the spiral channel flows, the channel average Nusselt numbers ratios between the smooth and twisted spiral channels were elevated to 1.18–1.09 but decreased with the increase of Dn or Re. A set of heat-transfer correlations for estimating the Nusselt numbers of Taylor flow in the rotor-to-stator air gap was newly devised from the data available in the literature. While the cooling effectiveness of the water jacket and shaft was boosted by the sectional twists along the spiral channel of the water jacket, the presence of Taylor flow in the annual air gap prohibited the effective rotor-to-stator heat transmission, leading to hot spots in the rotor. By way of airflow cooling through the rotating hollow shaft, the high temperatures in the rotor were considerably moderated. As the development of Taylor flow between the rotor and stator was inevitable, the development of active or passive rotor cooling schemes was necessary for extending the power density of an electric motor. Unlike the previous thermal circuit or lumped-parameter thermal model that predicted the overall temperatures of motor components, the present coupled electromagnetic and thermal-fluid model can reveal the detailed temperature distributions in an electric motor to probe the local hot spots of each component in order to avoid overheating at the early design stage.

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Effects of Fan Blade Forward-Swept and Inclined Amounts in Electric Motors

Cited by 8 publications

References 11 publications

Recent Developments in Cooling Systems and Cooling Management for Electric Motors

Recent Developments in Cooling Systems and Cooling Management for Electric Motors

Cooling of Automotive Traction Motors: Schemes, Examples, and Computation Methods

Heat Transfer and Thermal Management of Interior Permanent Magnet Synchronous Electric Motor

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