Evaluation of measurement techniques for gas flow characterization in the subchannels of a rodbundle during dry-out

For quantification of the thermal hydraulics in a heated rod bundle assembly the gas phase temperature and velocity in the subchannels has to be measured. The accessibility for sensors is strongly restricted due to the test facility design. In this paper the selection process for a suitable measurement device is presented. The approach is the modification of a wire-mesh sensor by implementation of special converters into the crossing points of the grid. Using a sensor material with a high thermal coefficient of resistance, both the resistance thermometer principle and the thermal anemometry principle, can be applicate by modulation of the sensor current.