Infrared High-Speed Thermography of Riblet-Structured Wall Surface Impinged by Diesel Spray Flame

Abstract

As a new tool to explore potential wall-structuring strategies for cooling loss reduction on diesel engine combustion chamber wall, a technique for high-speed thermography of riblet-structured wall surface impinged by a diesel spray flame was developed. The riblet structure was machined on a surface of a quartz window plate with ultra-sonic spindle, roughened with sand blasting and coated with 0.6m-thick chromium and 30nmthick SiO protection layers. The quartz plate was attached onto the inner surface of a pressure-proof quartz window for a constant-volume combustion chamber. The riblet-structured surface was impinged and heated by a single-shot diesel spray flame and the infrared radiation from the chromium coating was successfully visualized with high-speed infrared camera at 128 x 128 pixels resolution and 10kHz frame rate, enabling investigation on the effects of riblet structure on the previously reported radially striped temperature distribution and its advection velocity.