Design and off-design behavior of a tandem rotor stage

Abstract

With an ever-increasing focus on clean and sustainable energy for transport and power, aero-engine designers need to come up with engine designs that can meet the efficiency and thrust requirements. In this aspect, compressor/fan designers always aim at designs that can result in higher pressure ratios and maximum possible efficiency with a fewer number of stages. Compressor blades, which are designed for higher diffusion, have an inherent risk of flow separation. This, therefore, fixes the upper permissible limit in terms of diffusion. If the suction surface adverse pressure gradient can be efficiently managed to avoid flow separation, it would be possible to target higher diffusion factors. One such concept for achieving this is using tandem blading. In the present computational study, a conventional low-speed compressor stage performance is compared with a tandem stage. Both designs attempt similar levels of targeted diffusion. The computational results are simulated at the design and the off-design conditions. The computational results are validated with experimental data. A high percentage pitch and low axial overlap configuration are finalized for the design of the tandem rotor based on existing literature as well as initial parametric analyses. The study shows that it is possible to achieve higher diffusion for the tandem rotor in comparison to a single rotor. The behavior of the gap-nozzle, interaction of the tip leakage with the gap-nozzle, blockage due to the tip leakage vortex, performance of stator, and performance of both stages are discussed in detail in this paper.

Keywords

Axial flow compressor tandem blade gap-nozzle axial overlap percent pitch diffusion factor blade loading tip leakage vortex entropy

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References

McGlumphy J. Numerical investigation of subsonic axial-flow tandem airfoils for a core compressor rotor. PhD Thesis, Virginia Tech, 2008.

McGlumphy

Wellborn

, et al. Numerical investigation of tandem airfoils for subsonic axial-flow compressor blades. J Turbomach 2009; 131: 021018.

Wu G, Biaonan Z and Guo B. Experimental investigation of tandem blade cascades with double-circular arc profiles. In: ASME 1985 Beijing international gas turbine symposium and exposition, 1985, pp.V001T02A036. New York, NY: American Society of Mechanical Engineers.

Weber A and Steinert W. Design, optimization, and analysis of a high-turning transonic tandem compressor cascade. In: ASME 1997 international gas turbine and aeroengine congress and exhibition, 1997. New York, NY: American Society of Mechanical Engineers.

Hasegawa H, Akinori M and Shinya S. Development of highly loaded fan with tandem cascade. In: 41st aerospace sciences meeting and exhibit, 2003.

Müller L, Kozulovic D, Wulff D, et al. High turning compressor tandem cascade for high subsonic flows-part 2: numerical and experimental investigations. In: 47th AIAA/ASME/SAE/ASEE joint propulsion conference & exhibit, 2011, p.5602. San Diego, CA: AIAA.

Roy B, Mulmule A and Puranam S. Aerodynamic design of a part-span tandem bladed rotor for low speed axial compressor. In: 27th AIAA applied aerodynamics conference, 2009, p.3964. San Antonio, TX: AIAA.

Roy B and Saha UK. High diffusion cascades for axial flow compressor applications. In: Proceedings of 15th Canadian congress of applied mechanics, 1995, pp.356–363. Victoria, Canada: University of Victoria.

Roy

Saha

. On the application of variable camber blading in axial flow fans and compressors. In: ASME paper 96-TA: 58, 1996.

10.

Bammert

Beelte

. Investigations of an axial flow compressor with tandem cascades. J Eng Gas Turbines Power 1980; 102: 971–977.

11.

Bammert K and Staude R. New features in the design of axial-flow compressors with tandem blades. In: ASME 1981 international gas turbine conference and products show, 1981. New York, NY: American Society of Mechanical Engineers.

12.

Hergt A and Siller U. About transonic compressor tandem design: a principle study. In: ASME turbo expo 2015: turbine technical conference and exposition, 2015. New York, NY: American Society of Mechanical Engineers.

13.

Falla G and Canon A. Numerical investigation of the flow in tandem compressor cascades. Master's Thesis, Institute of Thermal Power Plants, Vienna University of Technology, Austria, 2004.

14.

Hah

. Effects of double-leakage tip clearance flow on the performance of a compressor stage with a large rotor tip gap. J Turbomach 2017; 139: 061006 .

15.

Kumar A and Pradeep AM. Performance evaluation of a tandem rotor under design and off-design operation. In: ASME turbo expo 2018: turbomachinery technical conference and exposition, 2018, pp.V02AT39A008. New York, NY: American Society of Mechanical Engineers.