New gas concentration measurement system for the PANDA containment test facility

The increased use of computational fluid dynamics code for analysis and design purposes demands high quality experimental data to validate the simulation codes. Experimental data of fluid stratification and stratification break-up phenomena are generated in the frame of OECD/SETH-2 project at the PANDA facility. A new gas concentration measurement system is presented that is based on speed of sound measurements. Speed of sound in gas mixtures is a unique function of the temperature and the fractions of the components and therefore can be used to compute the fractions in varying compositions. The speed of sound is measured indirectly measuring the time of flight of an ultrasound pulse between two ultrasound transducers. The 30 transducers employed proved to be able to withstand the unfavorable conditions inside the facility with temperatures of up to 110 °C and steam that may condense. A frame rate (1 frame = each transducer has been excited) of 1.6 Hz and a helium fraction resolution of 1.5% in steam are achieved.