UC Davis

To meet the performance, economic, and environmental goals of the future, aircraft engines need to improve. One way to accomplish this is by enhancing the thermodynamic cycle by using intercooling and/or recuperation such as is employed in the fuel-integrated energy recuperative aircraft (FIERA) engine. The primary goal of this research was to determine if multistage intercooling using only the stator blades of the compressor is sufficient to provide the heat transfer required to obtain appreciable improvements in engine and combustion performance. This was split into three investigations: a small-scale examination of a single airfoil heat exchanger, an analysis of an effectiveness-NTU model for a full-scale, multistage-intercooled, axial compressor, and an investigation of the combustion characteristics of thermally enhanced kerosene. This work helped to identify a few insights, as well as a few failings of the envisioned FIERA engine. First, it is likely that the fuel consumption at cruise is not sufficient to provide adequate heat sink potential to provide substantial compressor intercooling even if high values of heat exchanger effectiveness are achieved. Secondly, the area provided by compressor stators alone appear to be insufficient to realistically approach high effectiveness values. Lastly, cracking of the fuel would likely not take place in a solely intercooled engine unless an engine with a very high overall pressure ratio (>60:1), or an intercooled recuperative engine was used. Therefore, it is of the author’s opinion that using the fuel in a commercial turbofan engine to create a more complex thermodynamic cycle would not be worthwhile.