Comparison of Open and Closed Brayton Engines for Recuperated and Simple Cycles.

To quantitatively compare open and closed Brayton systems for their possible recuperated and simple cycle versions, a general performance analysis is developed. The results of this analysis are summarized in open and closed cycle design point performance maps. The maps present the performance output (such as cycle efficiency) over ranges of design values for the important cycle parameters of recuperation, gas turbine inlet temperature, and pressure ratio. For possible open and closed Brayton systems, cycle efficiency increases with either increasing values of recuperation or turbine inlet temperature, or both. To quantify these performance effects, the open and closed cycles are optimized with respect to pressure ratio.