Software used. All calculations presented in this article were performed in commercial AxSTREAM turbomachinery design and optimization software developed and distributed by SoftInWay Inc. (Burlington, MA, USA). Theoretical background of the software is described in [7].

Future development prospects. Development of counter-rotating turbine for aircraft engine gives a new opportunity for creation of counter-rotating fan or compressor, which also can significantly decrease engine length and mass. This research is now intensively performed by scientific institutions of different countries.

CONCLUSIONS

Differences between traditional axial and counter-rotating turbines from prospects of integral and detailed thermodynamic parameters in the flow path are summarized. Three designs were considered: initial traditional axial turbine design which was chosen as prototype, and two variations of counter-rotating designs with 4 and 6 stages. Summarizing the results obtained we can find that using counter-rotating turbine with the same number of stages as in the prototype it’s possible to obtain the same performance level, but to decrease turbine axial length by 30% and weight by eliminating vanes. In this case we can balance all disadvantages which are coming from the complication of design in counter-rotating turbine. The second counter-rotating design with 6 stages was considered as an example increasing performances keeping in the prototype dimensions ranges, but increasing efficiency by 0.7% compared to initial design.

Calculation for off-design operating modes showed that counter-rotating turbine efficiency is higher in wider ranges of rotation speeds which gives additional benefits, but for the final conclusion this part of research needs to be conducted jointly with compressor performance calculations. This means that use of a counter-rotating turbine gives the opportunity not only to decrease turbine weight and length but also to create more advanced designs in terms of aerodynamic quality and overall cost-efficiency.

REFERENCES

1 B. A. Ponomariov, Y.U. Sotsenko [1992], Using contra-rotating rotors for decreasing sizes and component number in small GTE., ASME, 92-GT-414

2 J. F. Louis [1985], Axial flow contra-rotating turbines, ASME, 85-GT-218, Houston, TX, USA

3 Cohen H., Rogers GFC, Saravanamuttoo HIH [1996], Gas Turbine Theory, 4th Edition, Longman, Harlow Essex, UK

4 Fang Xiang-Jun, WANG Ping [2008], Research of Supersonic Axial Vaneless Rotor-Rotor Turbine, GT2008-50509, Proceedings of ASME Turbo Expo-2008, Berlin

5 Lakshminarayana, B. [1996], Fluid Dynamics and Heat Transfer of Turbomachinery, John Wiley & Sons, Inc., New York

6 Tang Fei, Zhao Xiaolu, Xu Jianzhong [2008], The Application of Counter-Rotating Turbine in Rocket Turbopump, International Journal of Rotating Machinery, Volume 2008, Article ID 426023

7 L. Moroz, Y. Govorushchenko, P. Pagur [2006], A Uniform Approach To Conceptual Design Of Axial Turbine / Compressor Flow Path, The Future of Gas Turbine Technology 3rd International Conference 11-12 October 2006, Brussels, Belgium