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This study reports a novel alternative technique that can achieve simultaneous two-dimensional temperature and velocity measurements in gas flow. This method is combining phosphor thermometry and PIV operated by a single laser unit. The temperature distribution was obtained from phosphorescence by using two-color method, and the velocity distribution was obtained from two phosphor particle images which were taken in time series during the persistence of the phosphorescence. The measured temperature and velocity were agreed with that measured by thermocouple and that expected as theoretical distribution in the high-temperature gas flows, respectively.

The time of, and location where ignition first occurs in a diesel fuel spray were investigated in a rapid compression machine (RCM) using the two–dimensional techniques of silicone oil particle scattering imaging (SSI), and the planar laser induced fluorescence (LIF) of formaldehyde. Formaldehyde has been hypothesized to be one of the stable intermediate species marking the start of oxidation reactions in a transient spray under compression ignition conditions. In this study, the LIF images of the formaldehyde formed in a diesel fuel spray during ignition process have been successfully obtained for the first time by exciting formaldehyde with the 3rd harmonic of the Nd:YAG laser. SSI images of the vaporizing spray, and the LIF images of formaldehyde were obtained together with the corresponding time record of combustion chamber pressures at initial ambient temperatures ranging from 580 K to 790 K.