Search Results

Modern thermal propulsion systems (TPS) as part of hybrid powertrains are becoming increasingly complex. They have an increased number of components in comparison to traditionally powered vehicles leading to increased demand in packaging requirements. Many of the components in these systems relate to achieving efficiency gains, weight saving and pollutant reduction. This includes turbochargers and diesel or gasoline particulate filters for example and these are known to be very sensitive to inlet boundary conditions. When overcoming packaging requirements, sub-optimal flow distributions throughout the TPS can easily occur. Moreover, the individual components are often designed in isolation assuming relatively flat and artificially quiescent inlet flow conditions in comparison to those they are actually presented with. Thus, some of the efficiency benefits are lost through reduced component aerodynamic efficiency.

Particle Image Velocimetry has developed over the last decade into a relatively mature flow-field measurement technique, capable of providing insight into time averaged and instantaneous flows that in the past have not been readily accessible. The application of the method in the measurement and analysis of flows around road vehicles has so far been limited to a relatively small number of specialist applications, but its use is expanding. This paper reviews the modern digital PIV technique placing emphasis on the important considerations required to obtain reliable and accurate data. This includes comments on each aspect of the PIV process, including initial setup and image acquisition, processing, validation and analysis. A number of automotive case studies are presented covering different aspects of the method, including a diffuser exit flow, edge radius optimization, ‘A’ pillar flow and aerial wake flows.