DPIV Measurements of the HVAC Aerodynamics Inside a Passenger Car

DPIV (Digital Particle Image Velocimetry) measurements of the HVAC (Heat, Ventilation and Air Conditioning) system aerodynamics inside the compartment of a passenger car will be presented. The measurements were carried out in a commercial version of a car. No modifications were made to the car other than substituting the doors on the passenger side for transparent acrylic sheets. In DPIV the flow is seeded with particles with size in the order of microns and the flow is illuminated by a planar pulsed laser sheet. The particles scatter the light and one or more high speed cameras, synchronized with the laser pulses, record images of the illuminated particles. Image processing of the obtained images allows the calculation of the velocity flow field. The seeding for these experiments was produced using a custom made Laskin nozzle atomizer and olive oil.

Flow velocities were measured in several vertical longitudinal and transverse planes, as well as in horizontal planes, covering very large areas inside the cabin of the car with high spatial resolution. Results showing the mean and the standard deviation of the velocity flow fields inside the cabin will be presented. The work reveals how DPIV can be used in the design and validation process of HVAC systems, in order to study the instantaneous flow fields and the main structures inside the cabin for each HVAC configuration desired.