FKFS: Research in Motion: Aerodynamic Measurement Systems

Aerodynamic Measurement Systems

In addition to the systems permanently installed in the wind tunnels for measuring force, torque, pressure and speed, FKFS also has other measuring and visualization techniques available for aerodynamic testing.

Our measurement technology for aerodynamic testing includes:

Compact 6 component balance for aerodynamic force measurements on vehicle models and components
Different mobile systems for simultaneous pressure measurements with over 500 channels
Surface pressure measurement using "pressure taps" or special, adhesive flat pressure probes
Multi-hole probes for high-resolution spatial determination of flow speed and angle over time
Hot-wire anemometer for local flow speed measurement
Specially-developed radiator probes for cooling air flow measurements installed on the vehicle radiator (see below)
3D PIV system

Contact

Dr.-Ing. Timo Kuthada

Ph.: +49 711 685-67615

Airflow Measurements

Volume Flow Rate Measurements

Due to the generally cramped installation conditions and potential interferences, precise determination of volume flow rates is often tricky – particularly in air conditioning and ventilation equipment. FKFS has developed specialized solutions for this.

Determining the Cooling-Air Flow in Vehicles

When designing a control system providing variable cooling air flow, it is important to determine the actual volume flow through the radiator for different configurations, at an early phase in vehicle development. FKFS has developed radiator probes for this objective. The probes use a differential pressure method to determine local flow speeds across the radiator’s surface, which are then used to calculate the overall volumetric flow rate. For this purpose, the heat exchangers to be examined are fitted with the aforementioned FKFS radiator probes and, after calibration, are integrated into the vehicle. Compared with other measuring techniques to record the cooling air flow, this has proven to be a robust and compact approach. With this equipment, measurements can be taken both in the wind tunnel and on the road under load. The method can take into account the influence of a thermal load and the effect of fans. Not only does this method determine the overall volume flow rate, it also sheds light on the velocity distribution across the radiator’s surface.

Measuring Small Airflows

It is possible to measure small flow rates using a standardized orifice and an auxiliary fan. The static pressures before and after the measuring orifice (differential pressure method) are determined and converted into a corresponding volume flow rate. Thanks to the auxiliary fan, this measurement technique is free from interference and delivers an integral value as a result. Two identical volume flow rate test sections are currently available at FKFS. The measurement range is between approx. 1.5 to 45 liters per second.

Typical application examples at FKFS are:

Measuring the flow from the air vents for interior conditioning of the passenger compartment
Evaluation of volume flow rates in ventilated comfort seats in the vehicle
Determination of impedence of porous/perforated materials