Heat recovery improves part-load turbine sfc

Explains how energy efficiencies can be held almost constant for full- and half-load operation of gas turbine powered mobile generators via heat recovery techniques. Two basic types of gas turbine heat recovery systems are considered: recuperative and regenerative. Effectiveness of a heat recovery device is usually defined as a ratio of the actual air-side temperature rise to the maximum theoretical temperature rise. This theoretical increase would raise the air temperature to that of the gasside temperature. A prototype was prepared, the only modification to the existing model GTP36-51 being incorporation of recuperator ducting and addition of the recuperator itself. The test program's goal was to demonstrate sfc reduction of the order of 40%. Results, corrected to a sea-level, 15C day, adequately demonstrated the improvement. A 36% reduction in fuel consumption at a 30-kW load, and a 32% reduction at a 15-kW load, were demonstrated. For further sfc reduction, increased operating temperatures are essential. Optimized pressure ratio was found to lie between four and five to one. An engine rotor speed of 112,000 rpm was found necessary for the high-temperature component match. Concludes that heat recovery, together with the higher component efficiencies projected for 1983 and beyond, is expected to permitmore » an sfc of the order of 190 g/kWh for devices of the types described.« less