PULSE POWER SUPPLY FOR SUBMARINE ELECTROMAGNETIC LAUNCH

A 250 V D>C>, 15 KA FUEL CELL CAPABLE OF 40 ONE-SECOND BURSTS OF ENERGY, WITH ABOUT 6.5 SECONDS BETWEEN BURSTS, OF 3.75 MW, IS PROPOSED AS A PULSE POWER SUPPLY FOR SUBMARINE ELECTROMAGNETIC LAUNCH.A PRELIMINARY ANALYSIS TAKING INTO ACCOUNT VARIOUS FUEL CELL OPERATING VOLTAGES AND EFFICIENCIES AND DIFFERENT METHODS OF FUEL AND OXIDANT STORAGE INDICATES THAT THERE IS NO ADVANTAGE FROM THE OVERALL VOLUME VIEW POINT TO WORKING AWAY FROM THE MAXIMUM POWER POTENTIAL OF THE FUEL CELL. THE ANALYSIS REFLECTS A SMALL SENSITIVITY TO VOLTAGE CHANGES CLOSE TO THE MAXIMUM POWER POINT, GAINS IN THE FUEL CELL BEING COMPENSATED BY LOSSES IN STORAGE AND VICE VERSA. IT HAS BEEN SHOWN THAT ANY FUEL CELL USED IN THIS APPLICATION MUST BE USED AT HIGH POWER DENSITY, AND THE ENSEMBLE MUST BE OPTIMIZED AROUND THE CHARACTERISTICS OF THE FUEL CELL. IN PARTICULAR, THE FUEL CELL MUST BE LIGHT WEIGHT IN KG/M2, BUT MORE PARTICULARLY SHOULD OPERATE AT THE HIGHEST POSSIBLE CURRENT DENSITY TO MAKE 2 KW/KG FOR THE SYSTEM A REALITY. FUEL CELL RUGGEDNESS AND REALIABILITY WILL BE MOST IMPORTANT. FUEL CELL EFFICIENCY IS LESS IMPORTANT. FOR THIS REASON, THE USE OF THE PEM FUEL CELL WITH IMPROVED MEMBRANES (DOW CHEMICAL, POLYIMIDE AND CARBANION ACID POLYMERS) IS PROPOSED. IT HAS THE ADVANTAGE OF OPERATING AT LOW TEMPERATURE WITH RAPID START-UP FROM COLD, IT REQUIRES NO CORROSIVE ELECTROLYTE MANAGEMENT, IT HAS INFINITE LIFE ON STAND, AND IT CAN TOLERATE HIGH PRESSURE DIFFERENTIALS ACROSS ITS ELECTROLYTE MEMBRANE.