Optimization of Naval propulsion machinery

The optimum naval propulsion plant is considered to be the one with the least total weight of machinery plus fuel. Perturbations of a modern destroyer propulsion cycle, with standard equipment components, are considered. Boiler pressure, condenser pressure , low pressure turbine exhaust annulus area, condenser surface, and leaving loss are considered variable. Equations are derived which express the variations in weight of important components. Availability balance methods are .applied in order to relate component efficiencies to fuel weight. Theoretical and numerical proof is given that leaving loss can be optimized on the basis of minimum turbine and condenser weight, independent of the rest of the cycle. This reduces the computations necessary in "brute force" analysis by an order of magnitude . As an example of the method, an availability balance is made for DLG-6 at cruising condition. Using 1050 F steam, boiler pressures from 800 psia to 1600 psia, and a broad range of condenser-L.P. turbine combinations, best parameters are found for ranges of 3*000, 5 $000, 7^000, and 10,000 miles „ Optimum condenser pressure is found to be fairly constant at 1.35" Hg. Abs., for the cruising condition and 75 F cooling water. The example studied indicates that standardization of naval propulsion plants at 1200 psia is on the high side of the optimum.