DIRECT MEASUREMENTS OF IN-CYLINDER INTEGRAL LENGTH SCALES OF A TRANSPARENT ENGINE

This paper presents a hardware technology and its accompanying softwar e developed to measure the in-cylinder integral length scales of the f low inside a transparent four-stroke engine directly, using a fiber la ser Doppler velocimeter (LDV). A traverse table was designed to combin e two 1-component fiber optical probes to form an LDV system with the capability of both a-component single- point and 1-component two-point simultaneous measurements for velocities. This paper demonstrates the evaluation of radially separated lateral and longitudinal integral le ngth scales. The location was at a mid-plane of the top dead center (T DC) clearance height, and the engine was motored at a speed of 500 rpm . Data analysis was processed using statistical techniques and the phy sical meaning of the results was explained.