KTH Royal Institute of Technology

Project description

Electric machines where the stator is wound using so called hairpin windings has become a common choice in automotive applications thanks to the high slot-fill factor and compactness of the end windings that can be realized. In order to realize the level of compactness that is required in automotive applications, these electric machines are typically liquid (water/glycol or oil) cooled using cooling channels inserted in the stator housing. The end-space region can, however, be cooled using different means including air cooling (using wafters mounted on the rotor) or arrangements where oil is sprayed on the end-winding region directly by dripping/spraying oil on it or, through the centrifugal force, spraying oil on the end-winding region using a hollow-shaft rotor. While substantial work has been put on modeling spray-cooling arrangements, relatively little attention has been put on this specific application which renders an evaluation of the cooling capability of the electric machine difficult for a machine designer.

The overall aim of this post-doctoral project is to implement and study CFD-based models (using software available through KTH’s already available licenses) of different cooling arrangements of hairpin-wound electric machinery. Focus is, hence, put on model implementation for an emerging application rather than on development of new modeling approaches. The planned activities include:

  • Implementation of parameterized hairpin-winding and end-space geometries in three dimensions.
  • Implementation of the above mentioned cooling methods for the end-space regime.
  • Using the implemented models, determination of selected figure of merits including cooling capability, pump requirements, equivalent heat-transfer coefficients, etc. that can be used by a machine designer in order to select a suitable cooling arrangement for a specific automotive application. Rotor speed ranges and machine dimensions applicable both to passenger vehicles and long-haulage vehicles should be considered.
  • If time allows, analysis of the electromagnetic losses arising in the end-winding region.

KTH has a strong collaboration with several actors in the Swedish automotive industry and it is planned that industrial input from some of these manufacturers will be provided in order to study relevant applications. The project is further planned to be associated with the Swedish Electromobility Centre (SEC) to enable a contact network for the involved researcher with relevant industrial actors. This post-doctoral research project is funded by the STandUP for Energy research collaboration.

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Qualifications

Requirements

  • A doctoral degree or an equivalent foreign degree, obtained within the last three years prior to the application deadline.

We believe that a suitable candidate holds a PhD degree (or equivalent) and has a strong background in the use of CFD-based modeling in applications that could be modified to address the models outlined above. Expertise in the field of electric machinery is not mandatory and we, hence, also welcome applicants with a strong background in CFD-based modeling and with a desire in learning a new and interesting application field with great interest to Swedish industry. As a post-doctoral researcher, you are expected to lead your research in a very independent manner and you should be able to convey your research results in form of publications but also to colleague researchers focusing on electromagnetic design and control but not necessarily with a strong background in modeling fluid dynamics.

Great emphasis will be placed on personal competence and suitability.

Trade union representatives

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Application

Log into KTH's recruitment system in order to apply to this position. You are the main responsible to ensure that your application is complete according to the ad.

Your complete application must be received at KTH no later than the last day of application, midnight CET/CEST (Central European Time/Central European Summer Time).

Fixed term employment /temporary contract up to two years. 

About the employment

The position offered is for, at the most, two years

A position as a postdoctoral fellow is a time-limited qualified appointment focusing mainly on research, intended as a first career step after a dissertation.

Others

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Disclaimer: In case of discrepancy between the Swedish original and the English translation of the job announcement, the Swedish version takes precedence.

Type of employment Temporary position
Contract type Full time
First day of employment According to agreement
Salary Monthly salary
Number of positions 1
Full-time equivalent 100 %
City Stockholm
County Stockholms län
Country Sweden
Reference number J-2019-3288
Contact
  • Maria Forslycke, HR-handläggare, rekrytering@eecs.kth.se
  • Oskar Wallmark, Lektor, owa@kth.se
Published 18.Dec.2019
Last application date 01.Mar.2020 11:59 PM CET

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