The automotive ventilation test case: Investigation of the velocity field downstream of a benchmark vent using smoke visualization and hot-wire anemometry

摘要

Effective operation of ventilation outlets depends on more or less apparent details in their design and on the flow history in the supply channel. Regrettably, visual appearance of the dashboard commonly receives higher priority in design because of marketing demands. This leads to incorrectly designed ducts and vents, wrongly dimensioned fans and other faults. Having limited space due to the above-mentioned restrictions, ventilation system designers should be given detailed information on the effects of various changes in the design of the duct and vent. We have developed and experimentally investigated a benchmark ventilation channel which possesses main features of vents usually installed in panel boards and which allows incorporation of various components to facilitate the investigation of their influence on the flow. The jet emerging from the vent has been studied by smoke visualization and hot-wire anemometry in three basic configurations: a straight channel, a channel with a simple bend, and a channel with a bend equipped with turning vanes. The measurements proved that the effect of insertion of the bend to the channel is significant. It changes the shape of the jet core, while insertion of the turning vanes into the bend only causes homogenization of the core without changing the jet shape. This means that it is essential to always evaluate the performance of the ventilation outlet with its supply channel, as the flow history is difficult to eliminate by simple flow conditioning fixtures, such as turning vanes. The research results as well as digital geometry of the benchmark vent are freely available to all research groups that would like to use it for validation of their numerical simulations.