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Job Record #15393
Titlepost-doc
CategoryJob in Academia
EmployerChalmers University of Technology
LocationSweden, Gothenburg
InternationalYes, international applications are welcome
Closure DateMonday, December 31, 2018
Description:
As a new way for transportation, electric aircrafts have been attracting extensive attention due to low CO2 emission. However, low noise emission is crucial for electrical aircrafts to be accepted to transport in urban areas. Electric propulsion systems therefore need to be improved to reach this goal. Since the propellers of the systems are known to dominant the noise generation, we are doing esearch on reduction of propeller noise at Chalmers, particularly for electric aircrafts.

Boxprop, developed by Prof. Grönstedt’s group at Chalmers ( US patent, "Air propeller arrangement and aircraft") can be one concepts for the next generation of aircraft propellers. Several recent studies by Prof. Grönstedt’s group have shown that this concept has high potentials to improve the propulsion efficiency and noise emission.

Aims

This project aims to explore the potential usage of Boxprop for future short-range electrical aircrafts as a future public urban transportation service. The feasibility of Boxprop will be addressed and demonstrated based on numerical simulations and experiments. The aeroacoustic and aerodynamic performances of a set of propellers, which are designed with different geometrical parameters and rotational speeds, will be investigated. The findings will be used to improve the existing propeller configurations. Methods A high-fidelity computational fluid dynamics (CFD) method, detached eddy simulation (DES), will be employed in the flow simulation. This method can well resolve turbulent structures at high Reynolds numbers but consumes much less computational resources than direct numerical simulation (DNS) and large eddy simulation (LES). The Ffowcs Williams and Hawkings method (FW-H) will be used in the noise prediction. The FW-H method belongs to the family of the acoustic analogy originally proposed by Lighthill (1956). An apparent advantage of the FW-H method is that it separates the aeroacoustic and aerodynamic simulations. Therefore, numerical errors in the aerodynamic simulation will not contaminate the aeroacoustic prediction. The near- and far-field noise levels of the configurations at various rotational speeds will be measured in an anechoic chamber. The ambient air in the chamber is quiescent to make the free-stream velocity zero. Operations with multiple propellers will be tested to explore the interaction between propellers.

Measurements

The noise measurement will be carried out at the division of Applied Acoustics at Department of Architecture and Civil Engineering in Chalmers. The dimensions of the chamber are 10 m x 10 m x 8 m. The background noise level is controlled below 17dBA. The operational frequencies range from 75 Hz to 10 kHz.

The project is connected to the ELISE project (Electric Aviation in Sweden). It is a Vinnova financed project about electric aviation in Sweden. Anders is also running his own drone project for sparsely populated areas. The topic is small vessels to transport medicine between health centers and outlokalized so-called "health room" in Västerbotten inland. The drone is a carbon fiber structure in the order of two by two meters, capable of lifting 8 kilos and flying up to 70 kilometers.

Contact Information:
Please mention the CFD Jobs Database, record #15393 when responding to this ad.
NameLars Davidson
Emaillada@chalmers.se
Email ApplicationNo
URLhttp://www.chalmers.se/en/about-chalmers/Working-at-Chalmers/Vacancies/?rmpage=job&rmjob=6788
Record Data:
Last Modified14:31:21, Monday, October 15, 2018

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