Non-Intrusive Temperature Determination by LIF in Hypersonic Wind Tunnels

LIF excitation spectra of nitric oxide have been measured in a hot supersonic freejet expansion in the vacuum wind tunnel (V2G) in Goettingen to determinate rotational temperatures. To interprete the experimental results, a computer program was developed that calculates the excitation spectra for temperatures up to 2000 K. By means of the LIF measurements in the free flow and in front of a model surface details of the heat transfer can be examined; this is relevant for the gas-surface interaction studies of reentry vehicles