Open Jet Facility

Focus of the Faculty of Aerospace Engineering

The Faculty of Aerospace Engineering (AE) has various wind tunnel facilities at its disposal. The wind tunnels play an important role in both teaching and experimental scientific research for a vast range of subjects in aerodynamics. The wind tunnels are also used for research focused on the car industry and, for example, on industrial applications.

History

Initial plans for the OJF were drawn up back in the 1980s in response to growing interest in wind energy. The development was delayed because the wind energy research group switched faculty a number of times and a large budget was needed to construct a large open jet wind tunnel. Things began to move again when the wind energy group was taken under AE’s wing in 2003. AE demanded however, that the OJF should be used for more than just research into wind turbines. After all, the need for experimental research had increased dramatically due in part to the international climate and air pollution targets for 2020 and to the further development of Computational Fluid Dynamics (CFD).

Advantage of OJF

The OJF has an open jet and an outlet diameter of almost three metres and can handle very large models that obstruct airflow quite considerably. The new wind tunnel offers more possibilities than ever before for teaching (laboratory courses involving model rotors) and research (parameter studies can be executed more quickly than with numerical research).

Fantastic result

Construction of the OJF got underway in November 2006, and has meanwhile been completed. The OJF will be used mainly by PhD students, graduates and members of the permanent academic staff. It will fulfil an important role in research into the aerodynamic effects that wind can have on buildings and ships as well as in the field of sports. The vast majority of the models will be made in the faculty’s own workshop.

Extremely versatile

The OJF is extremely versatile. It is vitally important to the wind energy group for analysing purposes, such as the verification and validation of calculation models. The TUDelft continues to contribute to the large scale European research project that is currently taking place, searching for new concepts for wind turbine blades, including smart rotors. The aviation industry is also experiencing a growing demand for research into the properties of a new and smart wing technology.

Ins and outs of the OJF

The dimensions of the OJF are very impressive. A large fan powered by a 500 kilowatt electric motor enables it to achieve a maximum speed of around 120 kilometres an hour. Air is rotated 180 degrees through a long diffuser and two rows of corner vanes. It then passes through a short diffuser before entering the ‘settling chamber’. Here, five fine-mesh screens reduce the turbulence and velocity deviations in the airflow. Via a contraction the air is then blown into the test section as an even jet stream and cooled at the end by an enormous cooling radiator and guided back to the fan.

Exciting project

Geveke Klimaattechniek (Amsterdam) has supplied the fan that lies at the heart of the OJF. This company had been in the picture to supply the fan ever since the first designs for an open jet wind tunnel were conceived (1980s) and, following years of research and development, is satisfied with the end result. The fan was built at the FläktWoods factories in Sweden, and a team of experts from Geveke as well as employees of TUDelft made regular trips to Sweden to fine-tune the design. Geveke’s involvement with the OJF will continue in the area of problemsolving and maintenance.

Technical specifications

For Geveke, the construction of the OJF was a special project with many unique technical features, such as the high power of the motor, the modular adjustable frequency drive, the thermal sensors and the large cooling fan. Geveke had an important advisory role in the development process.

Facilities in abundance

Aerospace Engineering hosts many sophisticated facilities, some of them even unique for a faculty, such as its own laboratory aeroplane (Cessna Citation II), a large flight simulator (SIMONA), extensive Computational facilities and materials with a research laboratory. The OJF is in good company, being surrounded by a wide range of low-speed and high-speed wind tunnels.