A digital video camera for application of particle image velocimetry in high-speed flows

Abstract

A high-speed digital camera based on video technology for application of particle image vevocimetry in wind tunnels is described. The camera contains two independently triggerable interline CCD sensors which are mounted on two faces of a cube beam splitter permitting the use of a single lens. Each of the sensors has a minimal exposure time of 0.8 microsec. with a trigger response time of less than 1 microsec. The asynchronous reset capability permits the camera to trigger directly off a pulsed laser with a repetition rate differing from the standard 25 Hz CCIR video frame rate. Captured images are digitized whinin and stored in RAM the camera which can be read through the parallel port of a computer.The camera is software configurable with the settings being non- volatile. Technical aspects such as sensor alignment and calibration through software are described. Close-up PIV measurements on a free jet illustrate that, in the future, the camera can be successfully utilized at imaging high-speed flows over a small field of view covering several cm2, such as the flow between turbine blades. Further, the electionic shutter permits its use in luminous environments such as iluminated laboratories, wind tunnels of flames.