Bottoming Cycle for Intercooled gas Turbine Engines: Combined Cycle Based on CEC RFTE Topping Unit with Organic Fluid Bottoming Cycle

This is a preliminary exploration of design problems and expected performance of compact combined cycle engines for transportation applications consisting of an intercooled gas turbine as topping unit and a Rankine cycle as bottoming unit. The latter must take all or most of the required vaporizer heat from that rejected by the intercoolers and/or other flowpath coolers. Water is rejected as the Rankine cycle fluid, and organic heat transfer fluids are the only alternatives. The first task is to choose from available fluids one or two having the best combination of properties. Dowtherm J and Fluorinol-85 are strong candidates. Using one of these, the bottoming cycle combined with a topping unit based on CECs' Regenerative Feedback Turbine Engine (RFTE) is simulated to determine approximate performance and size of vaporizer/cooler, condenser, and turbine expander. Next make engine performance estimates and preliminary layouts of selected engine configuration. The RFTE based topping unit will result in compact low-emissions combined cycle engines of high efficiency (.46 to .55) and specific power (680-820). The commercial market for engines of such capabilities is enormous and the military market is quite significant. A proposed Optional task to provide preliminary design of the turbine expander is included.