Urith Archakositt, Sunchai Nilsuwankosit, and Tatchai Sumitra

pp. 559 - 568

Abstract

The experiments on the interaction between the liquid nitrogen and the water were conducted in
order to confirm its similarity with the interaction between the molten metal and the volatile liquid coolant,
the Fuel-Coolant Interaction (FCI). For the experiments, the water was injected from a pressurized water
bottle into a cylindrical interaction chamber to interact with the saturated liquid nitrogen that was filled
from the bottom. From the experiments, some of the obtained pressure profiles showed relatively strong and
sharp pressure spikes. This suggested the possibility of vapor explosion during the experiments. The propagation speeds of these pressure spikes could be calculated based on the time differences recorded by the
transducers at the top and at the bottom of the interaction chamber. Based on the results from an experiment
with the injection pressure of 4 bars and the volume ratio for the water and the liquid nitrogen of 0.10, the
propagation speed was calculated to be between 22 m/s to 50 m/s. This speed was found to be comparable
with the theoretical value for the sound speed in a mixture of liquid nitrogen and nitrogen gas. It was concluded that the observed pressure spikes were actually the movement of the shock wave and that vapor
explosion had actually occurred in this particular experiment.