Sensitivitätsanalyse der Wärmequellen- sowie Wärmetransportmodellierung in permanenterregten Synchronmaschinen

Beck, Christopher; Keller, Daniel; Echtle, Harald; Haug, Sebastian; Krüger, Christian; Bargende, Michael

doi:10.1007/s00502-019-0714-z

Cited by 5 publications

(2 citation statements)

References 12 publications

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“…This is done with a detailed three-dimensional finite volume solid model with analytical boundary conditions, which models the main cooling mechanisms and heat paths in the engine and relates the cooling performance to the flow conditions. 2 To reduce component temperatures, heat sinks should be close to heat sources.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigation of flow phenomena in rotating step-holes for direct-spray-cooled electric motors

Beck

Schorr

Echtle

et al. 2020

International Journal of Engine Research

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Despite their high efficiency, electric motors are thermally limited in some operating points by several types of losses. Whenever temperature–critical components threaten to overheat, the performance is reduced for component protection (derating). The use of a suitable cooling concept may reduce the derating. The design of efficient cooling concepts of electric motors in traction drives with increased power densities is challenging, caused by the fact that the heat releases in the components vary considerably with the operating point. One option to reduce the temperatures is to place the heat sinks close to heat sources. Therefore, direct spray cooling with nozzles located in the rotor shaft is often used for cooling the end windings. The dielectric fluid (e.g. oil) is introduced into the mainly air-filled interior of the electric motor. In the following study, the behavior of the jet in the rotating step-holes at different volumetric flow rates is examined. To carry out the investigation, a new test rig and a novel optically accessible electric motor were designed. In this specifically designed test environment, the shape of the jets of different operating points is investigated by direct high-speed visualization. The cinematography setup is made of a four-light-emitting diode system in combination with a high-speed camera. A combined approach of experiment and simulation is used to find basic mechanisms of spray formation produced by rotating step-holes. Depending on the volumetric flow rate and the rotational speed, the direction of the oil jet gets more curved in relation to the rotating nozzle after exiting the small bore. If the deflection is large, the jet impinges on the wall of the large bore before reaching the end of the nozzle. The jet formation at the exit of the step-hole is mainly driven by the divergent forces in the liquid caused by impingement and the counteracting Coriolis force. Depending on the volumetric flow rate with constant rotational speed, different cross-sectional shapes of the jet at the exit are observed. These characteristic shapes can be grouped as a round undisturbed jet, strands with a connecting lamella and a C-shaped cross-section.

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Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigation of flow phenomena in rotating step-holes for direct-spray-cooled electric motors

Beck

Schorr

Echtle

et al. 2020

International Journal of Engine Research

Self Cite

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“…More holistic thermal sensitivity studies, on the other hand, do not compare different cooling concept combinations but rather focus on parameters such as thermal conductivity, thermal contact resistance and convection inside an enclosed machine [11,12] or concentrate on a fixed cooling concept [13,14]. This does not, however, adequately cover all of the versatile influencing parameters: In addition to the combination of cooling concepts, the thermal designer must calculate the optimum geometry of the cooling system and choose the volume flow rates in order to find the best compromise between heat transfer, energy consumption of the coolant pumps and complexity of mechanical integration.…”

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confidence: 99%

Comparison of Commonly Used Cooling Concepts for Electrical Machines in Automotive Applications

et al. 2022

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The thermal design of electrical machines has numerous influencing factors. This paper compares different cooling methods, their volume flow rates and other machine parameters with regard to the continuous power of a PMSM. Understanding the characteristics of different heat sinks depending on their operating point is important for an expedient design in order to avoid derating due to overtemperatures. As a design guideline, this contribution shows the influence of stator cooling jackets, rotor shaft cooling and direct end winding cooling for different machine lengths and volume flow rates. Both water and oil are investigated as coolants. With increasing machine dimensions, end winding cooling becomes less effective for heat sources in the center of the machine while the heat transferred in the cooling jacket increases. A sensitivity study of other machine parameters, such as the maximum allowed magnet temperature or the coolant inlet temperature, improves the understanding of the reader as to how the continuous power of a PMSM can be increased when the rotor temperature limits the performance.

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Numerische Analyse einer nasslaufenden permanenterregten Synchronmaschine

Beck

Krüger

Schorr

2021

Elektrotech. Inftech.

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Sensitivitätsanalyse der Wärmequellen- sowie Wärmetransportmodellierung in permanenterregten Synchronmaschinen

Cited by 5 publications

References 12 publications

Numerical and experimental investigation of flow phenomena in rotating step-holes for direct-spray-cooled electric motors

Numerical and experimental investigation of flow phenomena in rotating step-holes for direct-spray-cooled electric motors

Comparison of Commonly Used Cooling Concepts for Electrical Machines in Automotive Applications

Numerische Analyse einer nasslaufenden permanenterregten Synchronmaschine

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