As a demonstration of a new method to examine the extremely unsteady and spatially varying wall heat transfer phenomena on diesel engine combustion chamber wall, high-speed imaging of infrared thermal radiation from the wall surface impinged by a diesel spray flame was attempted using a high-speed infrared camera. A 35 mm-diameter chromium-coated quartz window surface was impinged by a diesel spray flame with an impinging distance of 27 mm from the nozzle orifice in a constant volume combustion chamber. The infrared thermal radiation from the back surface of the 0.6 µm thick chromium layer was successfully visualized at 10 kHz frame rate and 128 × 128 pixel resolution through the quartz window. The infrared radiation exhibited coherent and streaky structure with radial stripes extending and waving from the stagnation point. The width of the radial stripes, spatial amplitude and the period of the waving movement were comparable to the ones for turbulent heat transfer on the engine cylinder wall previously measured with a heat flux sensor, suggesting that they are resulting from the turbulent structure in the wall-impinging diesel flame. The radiation intensity was calibrated to temperature and converted to heat flux via 3-D numerical analysis of transient thermal conduction in the quartz window. The peak-to-peak variation amplitudes of temperature and heat flux among the radial stripes during the diesel spray flame impingement were about 20 K and 2.3 MW/m², corresponding to 13% of 150 K maximum temperature swing amplitude and 18 MW/m² maximum heat flux, respectively.

为了验证检查柴油发动机燃烧室壁上极不稳定和空间变化的壁传热现象的新方法，尝试使用高倍数的高速成像技术对由柴油喷雾火焰撞击的壁表面产生的红外热辐射进行高速成像。高速红外摄像机。在恒定容积燃烧室中，直径35 mm的镀铬石英窗表面被柴油机喷出的火焰撞击，距喷嘴孔的撞击距离为27 mm。通过石英窗口以10 kHz帧频和128×128像素分辨率成功观察到了0.6 µm厚铬层背面的红外热辐射。红外辐射表现出连贯的条纹状结构，径向条纹从停滞点开始延伸并呈波浪形。径向条纹的宽度，空间振幅和波动的持续时间与以前使用热通量传感器测量的发动机汽缸壁上湍流传热的辐射带相当，表明它们是壁中的湍流结构产生的-撞击柴油机火焰。通过对石英窗口中瞬态热传导的3-D数值分析，将辐射强度校准为温度，并将其转换为热通量。柴油机喷雾火焰撞击期间径向条纹之间温度和热通量的峰峰值变化幅度分别约为20 K和2.3 MW / m 这表明它们是由撞击壁的柴油机火焰中的湍流结构引起的。通过对石英窗口中瞬态热传导的3-D数值分析，将辐射强度校准为温度，并将其转换为热通量。柴油机喷雾火焰撞击期间径向条纹之间温度和热通量的峰峰值变化幅度分别约为20 K和2.3 MW / m 这表明它们是由撞击壁的柴油机火焰中的湍流结构引起的。通过对石英窗口中瞬态热传导的3-D数值分析，将辐射强度校准为温度，并将其转换为热通量。柴油机喷雾火焰撞击期间径向条纹之间温度和热通量的峰峰值变化幅度分别约为20 K和2.3 MW / m^2分别对应于150 K最大温度摆幅的13％和18 MW / m ²最大热通量。