Real time x-ray imaging and measurements of coolant injection mode vapor explosions

A new facility has been developed to study the explosive interactions of gas-water injection into a molten tin pool. The experimental apparatus allows for variable nitrogen gas and water injection into the base of a steel tank containing molten tin. A first set of experiments based on gas injection only, has been used to develop a diagnostic technique using real-time high energy x-rays to observe the mixing process and measure local and average void fraction in the test section. Void fraction measurements with superficial gas injection rates of 7.0 cm/sec to 14 cm/sec into an 8 cm deep pool of 683 K molten tin, indicate that the average void fraction at these gas injection rates is relatively constant, in the range of 36% to 40%. Similar injections into a pool of 14 to 15 cm depths exhibited void fractions in the range of 18% to 23%. Initial experiments with simultaneous water and nitrogen gas injection have demonstrated the ability to produce energetic interactions in the coolant injection geometry with water flow rates of 0.8 x 10-2 kg/sec to 2.5 x 10-2 kg/sec. 13 refs., 4 figs., 1 tab