Optimizing Dump Diffuser in Gas Turbine by Bleeding Air Method and Vortex Generators
Main Article Content
Abstract
The diffuser is a component that connects the combustion chamber and the compressor in a gas turbine engine. Its main function is to slow down the airflow supplied by the compressor to enhance efficient combustion and avoid excessive total pressure loss. Therefore, the effectiveness of the diffuser is evaluated based on two values: the total pressure loss coefficient and the static pressure recovery coefficient. The smaller the total pressure loss coefficient, the better the static pressure recovery coefficient. In previous studies, attention and research have been given to the inlet angle of the diffuser. It has been observed that there is a clear flow separation on the diffuser wall before the angle of the front diffuser wall is extended to a certain degree. This increases the region of recirculation vortices, thereby increasing the total pressure loss of the system and adversely affecting the performance of the diffuser. However, there have been few studies addressing this issue. In this research, two methods are introduced to improve the diffuser: the bleeding air system and the using vortex generators. This study used numerical methods to simulate the 3D model of the diffuser. The computational results show that swirl generators and air injection methods can be observed to delay the separation process in the front diffuser and reduce the total pressure loss and improve the performance of dump diffuser by over 20%.
Keywords
dump diffuser, pressure loss, flame tube, vortex generator, bleeding air
Article Details
References
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[17]. M. B. Bragg and G. M. Gregorek, Experimental study of airfoil performance with vortex generators, J Aircr, vol. 24, no. 5, 1987, https://doi.org/10.2514/3.45445.
[2]. K. C. Karki, V. L. Oechsle, and H. C. Mongia, A computational procedure for diffuser-combustor flow interaction analysis, J Eng Gas Turbine Power, vol. 114, no. 1, 1992, https://doi.org/10.1115/1.2906301
[3]. S. Honami, W. Tsuboi, and T. Shizawa, Effect of the flame dome depth and improvement of the pressure loss in the dump diffuser, in Proceedings of the ASME Turbo Expo, 1998, https://doi.org/10.1115/98-GT-225.
[4]. J. F. Carrotte, D. W. Bailey, and C. W. Frodsham, Detailed measurements on a modern combustor dump diffuser system, J Eng Gas Turbine Power, vol. 117, no. 4, 1995, https://doi.org/10.1115/1.2815453.
[5]. L. L. Xu, C. Ruan, X. Y. Fang, F. Xing, and C. L. Zhao, Effects of pre-diffuser on performance of dump diffuser, Tuijin Jishu/Journal of Propulsion Technology, vol. 36, no. 7, 2015, https://doi.org/10.13675/j.cnki.tjjs.2015.07.013.
[6]. J. F. Garrotte, P. A. Denman, A. P. Wray, and P. Fry, Detailed performance comparison of a dump and short faired combustor diffuser system, J Eng Gas Turbine Power, vol. 116, no. 3, 1994, https://doi.org/10.1115/1.2906850.
[7]. R. Hestermann, S. Kim, A. Ben Khaled, and S. Wittig, Flow field and performance characteristics of combustor diffusers: A basic study, J Eng Gas Turbine Power, vol. 117, no. 4, 1995, https://doi.org/10.1115/1.2815454.
[8]. S. Honami, T. Shizawa, A. Sato, and H. Ogata, Flow behavior with an oscillating motion of the impinging jet in a dump diffuser combustor, J. Eng Gas Turbine Power, vol. 118, no. 1, 1996, https://doi.org/10.1115/1.2816551.
[9]. P. Ghose, A. Datta, and A. Mukhopadhyay, Effect of prediffuser angle on the static pressure recovery in flow through casing-liner annulus of a gas turbine combustor at various swirl levels, J Therm Sci Eng Appl, vol. 8, no. 1, 2016, https://doi.org/10.1115/1.4030734.
[10]. S. Shen, M. Shang, P. He, and M. Ronghai, The effects of cowling geometry, area ratio and dump gap on a combustor diffusion system, in Proceedings of the ASME Turbo Expo, 2014. https://doi.org/10.1115/GT2014-26652.
[11]. H. Wang and K. H. Luo, Numerical investigation of dump diffuser combustor performance at uniform and non-uniform inlet conditions, in Proceedings of the ASME Turbo Expo, 2020, https://doi.org/10.1115/GT2020-15982.
[12]. S. Pönick, D. Kozulović, R. Radespiel, B. Becker, and V. Gümmer, Numerical and experimental investigations of a compressor cascade flow with secondary air removal, J. Turbomach, vol. 135, no. 2, 2012, https://doi.org/10.1115/1.4006570.
[13]. V. Peltier, K. Dullenkopf, and H. J. Bauer, Experimental investigation of the performance of different bleed air system designs, in Proceedings of the ASME Turbo Expo, 2012, https://doi.org/10.1115/GT2012-68242.
[14]. B. Zhao, S. Li, Q. Li, and S. Zhou, The impact of bleeding on compressor stator corner separation, in ASME-JSME-KSME 2011 Joint Fluids Engineering Conference, AJK 2011, 2011, https://doi.org/10.1115/AJK2011-22001.
[15]. S. D. Grimshaw, G. Pullan, and T. Walker, Bleed-induced distortion in axial compressors, J. Turbomach, vol. 137, no. 10, 2015, https://doi.org/10.1115/1.4030809.
[16]. F. Xing, H. Su, S. Chan, L. Xu, and X. Yu, Optimization study of the dump diffuser in gas turbine to reduce pressure loss, International Journal of Aerospace Engineering, vol. 2018, 2018, https://doi.org/10.1155/2018/6070782.
[17]. M. B. Bragg and G. M. Gregorek, Experimental study of airfoil performance with vortex generators, J Aircr, vol. 24, no. 5, 1987, https://doi.org/10.2514/3.45445.