LIF and chemiluminescence methods for the flow diagnostics of supersonic mixing chemical lasers

Two methods are described for investigating a supersonic mixing chemical laser flowfield. The first is a refinement of the LIF (laser-induced fluorescence) method proposed by Rapagnani et al. (1979). Here, distinct shock patterns are obtained. The second method involves measuring the spatial intensity profile of the HF overtone emission in a 'hot' reactive flow. It is thought that the results will aid in understanding the nature of diffusion between fuel and oxidizer streams in a supersonic chemical laser. It is noted that in a CW HF chemical laser, the inversion is produced by the supersonic mixing of initially separate oxidizer (F) and fuel (H2) streams with a subsequent reaction inside the optical cavity. The process of mixing is a controlling step, and the laser performance is strongly dependent on it. The investigation of the flowfield is therefore regarded as an important aspect for studying this type of laser.