Effect of Swirl on the Performance of an Annular Diffuser

Abstract:

Annular diffusers are primarily used to convert the kinetic energy of the exhaust flow into pressure energy. The performance of the diffusers are often measured using pressure recovery maps, that generally do not consider the distortion of flow at the inlet due to other upstream machine components. A high swirl velocity at the inlet could often account for large energy losses and hence it is necessary to curb the swirl component by appropriate design considerations. In this present work,it is desired to establish the swirl number range at the inlet of an annular diffuser for its effective and efficient performance and increased pressure recovery of the diffuser. “Swirl effect” on the fluid flow parameters with and without struts is compared, to give the idea of the numerical variation in the parameters.Computational fluid dynamics (CFD) analysis was performed to determine the maximum pressure recovery based on variations in the inlet swirl number. Thus, the flow was studied under varied conditions and a relation between the input parameters and the general pattern of flow for the specified input conditions was critically examined.

• Periodical: Applied Mechanics and Materials (Volume 787)
• Pages: 318-321
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.787.318
• Online since: August 2015
• Authors: R. Prakash, V. Karthik Srinivas, H. Anand, G. Adithya, N. Lakshmi Narayanan
• Keywords: Annular Diffuser, Inlet Swirl, Struts, Swirl Number, Turbulence, Turbulent Kinetic Energy

References

[1] Sovran, G. and Klomp, E. D. Experimentally determined optimum geometries for rectilinear diffusers with rectangular, conical or annular cross-section, Fluid Mechanics of Internal flow, ed., G. Sovran, Elsevier publishing company, Amsterdam, 1967, pp.270-319.

[2] Adenubi, S. O., Performance and flow regime of annular diffusers with axial turbo machine discharge inlet conditions. ASME Journal of Fluids Engineering, 98(1976), 236 – 242.

DOI: 10.1115/1.3448273

[3] Stevens, S. J. and Williams, G. J. The influence of inlet conditions on the performance of annular diffusers. ASME Journal of Fluids Engineering, 102(1980), 357–363.

DOI: 10.1115/1.3240694

[4] Sharan, V. K. Diffuser performance correlation. J. Aeronaut. Soc. India, 24(1972), 415 – 419.

[5] Sheeba, A. and Ganesan, V., Modeling of prediffuser for marine gas turbine combustor using CFD- A study on the effect of strut configuration, Journal of Naval Architecture and Marine Engineering, 29(2005), 41-52.

DOI: 10.3329/jname.v2i2.1871

[6] Singh, S.N., Seshakiri, V., Saha, K., Vempat, K.K. and Bharani, S., Effect of inlet swirl on the performance of annular diffusers having the same equivalent cone angle, Part G: Journal of Aerospace Engineering, 220(2005), 129-143.

DOI: 10.1243/09544100g05004

[7] Shuja, S. Z. and Habib, M. A. Fluid flow and heat transfer characteristics in axisymmetric annular diffusers, International Journal of Computers and Fluids, 25(1996), 133–150.

DOI: 10.1016/0045-7930(95)00033-x

[8] Eckert, W. T., Johnston, J. P., Simon, T. D., Mort, K. W., and Page, V. R. An experimental investigation of two large annular diffusers with swirling and distorted inflow, NASA-A-7436. NATIONAL AERONUATICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER, (1980).

[9] Adkins, R.C., A short diffuser with low pressure loss, ASME Journal of Fluids Engineering, 119(1975), 297-302.

DOI: 10.1115/1.3447306

[10] Adkins, R. C. and Montazerin, N., A hybrid diffuser with distorted inflow, ASME paper 85-IGT-109, (1985).

[11] Ubertini, S. and Desideri, U. Experimental performance analysis of an annular diffuser with and without struts, Experimental Thermal and Fluid Science, 22(2000), 183–195.

DOI: 10.1016/s0894-1777(00)00025-x

[12] R. Prakash, N.V. Mahalakshmi, Experimental investigations of flow through Annular Diffuser with and without Struts, European Journal of Scientific Research, 52(2011), 366-384.