Effect of Aerodynamic Blade Change of Two-Stage Axial Subsonic Turbine on Design Point

Document Type: Original Article

Authors

Department of Mechanical Engineering, Malek Ashtar University of Technology, Iran

Abstract

In this research for reducing the effect of losses and increasing the efficiency, the bowing in the rotor and stator blades is used. In one mode rotor blades are curved and in other one, stator blades are curved. The amount of rotor loss, due to changes in the thickness of the trailing edge and operating rotational speed, have been investigated. To confirm the accuracy of the results, a turbine stage whose experimental results are available is modeled and numerical results have been compared with experimental results that indicate acceptable compliance. The turbulence model k-w-SST is used to solve turbulent flow. The positive bowing, creates a pressure gradient from the two ends of the blade towards the center of the blade, which leads to the directing of the secondary flows toward the center of the blade. This reduces the losses in the two ends of the blade and increases the loss in the middle part of the blade. Increasing the thickness of the trailing edge, as well as increasing the turbine’s operating rotational speed, will increase the loss. The curved rotor increases the efficiency and mass flow and power by 0.4% and 0.5% and 0.8% respectively and the curved nozzle reduces the efficiency and power by 0.3% and 4.9% but increases the mass flow by 0.2%. It also increases the thickness of the trailing edge of the first rotor from 0.2mm to 0.9mm at 24000 rotational speed and increases the total loss by about 35%.

Keywords

Main Subjects


[1]     Karrabi,H., Rezasoltani, M., The Effect of Blade Lean, Twist and Bow on the Performance of Axial Turbine at Design Point, No. 54877, pp. 965-972, 2011.

[2]     M. Deich, M., Gubarev, A., Filipov, G., and Wang, Z. C., A New Method of Profiling the Guide Vane Cascades of Turbine Stages with Small Diameter-Span Ratio, Teploenergetika, Vol. 8, pp. 42-46, 1962.

[3]     Breugelmans, F. A. H., Carels, Y., and Demuth, M., Influence Of Dihedral on the Secondary Flow in a Two-Dimensional Compressor Cascade, Journal of Engineering for Gas Turbines and Power, Vol. 106, No. 3, pp. 578-584, 1984.

[4]     Shang, E., Wang, Z. Q., and Su, J. X., The Experimental Investigations on the Compressor Cascades With Leaned and Curved Blade, No. 78880, pp. V001T03A018, 1993.

[5]     Weingold, H. D., Neubert, R. J., Behlke, R. F., and Potter, G. E., Bowed Stators: An Example of CFD Applied to Improve Multistage Compressor Efficiency, Journal of Turbomachinery, Vol. 119, No. 2, pp. 161-168, 1997.

[6]     Fischer, A., Riess, W., and Seume, J. R., Performance of Strongly Bowed Stators in a Four-Stage High-Speed Compressor, Journal of Turbomachinery, Vol. 126, No. 3, pp. 333-338, 2004.

[7]     Tan, C., Yamamoto, A., Mizuki, S., and Chen, H., Influences of Blade Bowing on FlowFields of Turbine Stator Cascades, AIAA Journal, Vol. 41, No. 10, pp. 1967-1972, 2003.

[8]     Tan, C., Yamamoto, A., Chen, H., and Mizuki, S., FlowField and Aerodynamic Performance of a Turbine Stator Cascade with Bowed Blades, AIAA Journal, Vol. 42, No. 10, pp. 2170-2171, 2004/10/01, 2004.

[9]     Tan, C Zhang, H. Chen, H., and Yamamoto, A., Blade Bowing Effect on Aerodynamic Performance of a Highly Loaded Turbine Cascade, Journal of Propulsion and Power, Vol. 26, No. 3, pp. 604-608, 2010/05/01, 2010.

[10]  Schobeiri, M. T., Suryanarayanan, A., Jermann, C., and Neuenschwander, T., A Comparative Aerodynamic and Performance Study of a Three-Stage High Pressure Turbine With 3-D Bowed Blades and Cylindrical Blades, No. 41707, pp. 1237-1246, 2004.

[11]  Hassan Vand, M., Wang, S., Numerical Study of the Effects of Bowed Blades on Aerodynamic Characteristics in a High Pressure Turbine, No. 47306, pp. 487-496, 2005.

[12]  L. Chen, L., Liu, X. J., Yang, A. L., and Dai, R., Flow Performance of Highly Loaded Axial Fan with Bowed Rotor Blades, IOP Conference Series: Materials Science and Engineering, Vol. 52, No. 4, pp. 042005, 2013.

[13]  Koch,L. S. C., Loss Sources and Magnitude in Axial Flow Compressor, ASME J, pp. 354-363, 1976.

[14]  Wisler, D. C., Loss Reduction in Axial-Flow Compressors Through Low-Speed Model Testing, Journal of Engineering for Gas Turbines and Power, Vol. 107, No. 2, pp. 354-363, 1985.

[15]  Zheng, X., Li, Z., Blade-End Treatment to Improve the Performance of Axial Compressors: An Overview, 2016.

[16]  Ennil, A. B., Al-Dadah, R., Mahmoud, S., Rahbar, K., and AlJubori, A., Minimization of Loss in Small Scale Axial Air Turbine Using CFD Modeling and Evolutionary Algorithm Optimization, Applied Thermal Engineering, Vol. 102, pp. 841-848, 2016/06/05/, 2016.

[17]  Freeman,C., Effect of Tip Clearance Flow on Compressor Stability and Engine Performance, 2018.

[18]  Bini, R., Colombo, D., Large Multistage Axial Turbines, Energy Procedia, Vol. 129, pp. 1078-1084, 2017/09/01/, 2017.

[19]  Lindquist Whitacker, L. H., Tomita, J. T., and Bringhenti, C., An Evaluation of the Tip Clearance Effects on Turbine Efficiency for Space Propulsion Applications Considering Liquid Rocket Engine Using Turbopumps, Aerospace Science and Technology, Vol. 70, pp. 55-65, 2017/11/01/, 2017.

[20]  Majumdar, S., Role of Underrelaxation in Momentum Interpolation for Calculation of Flow with Nonstaggered Grids, Numerical Heat Transfer, Vol. 13, No. 1, pp. 125-132, 1988/01/01, 1988.

[21]  Chima, R., Liou, M. S., Comparison of the AUSM+ and H-CUSP Schemes for Turbomachinery Applications, Fluid Dynamics and Co-Located Conferences in: 16th AIAA Computational Fluid Dynamics Conference, Eds.: American Institute of Aeronautics and Astronautics, 2003.

[22]  Groschup, G., Strömungstechnische Untersuchung einer Axialturbinenstufe im Vergleich Zum Verhalten Der Ebenen Gitter Ihrer Beschaufelung: Dissertation, University of Hanover, 1977.

[23]  Zhongqi, L. S. W., Wenyuan, X., Aerodynamic Calculation of Turbine Stator Cascade with Curvilinear Leaned Blades and Some Experimental Results, in 5th International Symposium on Air Breathing Engine, 1981.

[24]  Wang, S., Wang, Z., and Feng, G., Numerical Simulation of 3D Flow Field Structure in Turbine Cascade With Bowed Blades, No. 78507, pp. V001T03A064, 2001.