Helicopter engines of the next decade will exhibit significantly improved performance if current Research and Development programs are pursued to their full potential. Small nonregenerative turboshaft engines in the 800-to-1200 horsepower class are projected to have cycle pressure ratios in the range of 18 to 22:1 and turbine inlet temperatures of about 2800 R. Specific fuel consumption will approach 0.4 lbm/hp/hr. Compressors used in future engines will achieve this cycle pressure ratio by using fewer stages. Configurations consisting of a combination of axial and centrifugal stages or dual centrifugal stages are viable approaches. The centrifugal compressors will have leanback impellers to improve efficiency tip range. The turbine will be aerodynamically, highly loaded with active clearance control to minimize tip clearance and secondary losses. Advanced materials such as single crystal blades will be used to extend life and reduce cooling losses. Advanced materials such as single crystal blades will be used to extend life and reduce cooling requirements. Environmental controls will become more severe requiring that more emphasis be placed on developing combustors having low emissions. And finally, because of the escalation of fuel prices, the regenerative turboshaft engine will receive more attention for helicopter applications with long duration mission requirements. (Wassmann)
Aerodynamic components for small turboshaft engines
Aerodynamische Bauteile fuer kleine Turbolufttrahltriebwerke
1981
15 Seiten, 23 Bilder
Conference paper
English
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