Design and testing of a wavelength-multiplexed TDLAS sensor for augmentor performance using an immersed water-cooled probe

A traversable, in-situ, water-cooled probe was designed, built, and tested to make tunable diode laser temperature measurements in a bluff-body stabilized flame simulating a jet engine augmentor. The combusting flow field was characterized by a Reynold’s number of 15,000 for all experiments, clearly in the turbulent regime. Two stability conditions have been documented for such flows previously, stable and unstable. The stable flow is characterized by small Kelvin -Helmholtz vortices relative to the size of the bluff body. In the unstable regime near the lean extinction limit, the flow becomes unstable displaying large-scale Karmen-Street vortices. We have, for the first time, performed high speed (up to 1 kHz) temperature measurements in such a flow field with approximately 2.5 cm spatial resolution. The results show large temperature fluctuations in the unstable regime near lean extinction as expected.