Measuring NO and OH Concentrations at High Pressure

An apparatus based on line-of-sight resonant absorption of ultraviolet light yields measurement data from which one can calculate the concentrations of nitric oxide (NO) and of hydroxyl radicals (OH) in a laboratory flat flame at a pressure up to 30 atm ≈3 MPa). The basic measurement principle is distinct from the principles of laser-induced fluorescence and other laser diagnostic techniques; hence, the data generated by this apparatus could provide independent verification of data from laser-based instruments.