Biphase Turbine Bottoming Cycle for a Diesel Engine

摘要

Application of a two-phase turbine system to waste heat recovery was examined. Bottoming cycle efficiencies ranging from 15 to 30% were calculated for a 720 exp 0 F diesel exhaust temperature. A single stage demonstration unit, designed for non-toxic fluids (water and Dow-Therm A) and for atmospheric seals and bearings, had a cycle efficiency of 23%. The net output power was 276 hp at 8,100 rpm, increasing the total shaft power from 1,800 hp for the diesel alone, to 2,076 hp for the combined system. A four stage organic turbine, for the same application, had a rotational speed of 14,700 rpm while a four stage steam turbine had 26,000 rpm. Fabrication drawings were prepared for the turbine and nozzle. The major improvement leading to higher cycle efficiency and lower turbine rpm was found to be the use of a liquid component with lower sensible heat. A possible reduction in capital cost was found to be the use of a contact heat exchanger instead of tube-fin construction. A program resulting in the demonstration of a two-phase bottoming system was planned and the required cost estimated. The program would result in a feasibility test of the nozzle and turbine at the end of the first year, a laboratory performance test of the bottoming system by the end of the second year, and a field demonstration test and laboratory endurance test of the bottoming system during the third year.