Development of a Pebble-Bed Liquid-Nitrogen Evaporator and Superheater for the Scaled Large Blast/Thermal Simulator Facility

In the context of feasibility studies for the U.S. Large Blast Thermal Simulator LBTS facility, a 148-scale model pebble-bed LN2 heat exchanger was designed and built that would produce hot nitrogen gas at a predetermined temperature from a cryogenic LN2 source at pressures up to 1700 psig and at a flow rate sufficient to fill the LBTS driver tubes rapidly enough to minimize heat losses through the uninsulated driver walls and to maintain the required nitrogen gas temperatures. The pebble-bed LN2 evaporator and superheater was successfully tested and delivered. The results of the test will be used to provide design data for a larger pebble-bed LN2 evaporator and superheater to be used in a 16-scale LBTS test-bed facility under development at BRL, and eventually for the full-scale LBTS facility.