Abstract
Numerical simulations have been performed to investigate tip clearance effect on through-flow and performance of a centrifugal compressor which has the same configuration of impeller with six different tip clearances. Secondary flow and loss distribution have been surveyed to understand the flow mechanism due to the tip clearance. Tip leakage flow strongly interacts with mainstream flow and considerably changes the secondary flow and the loss distribution inside the impeller passage. A method has been described to quantitatively estimate the tip clearance effect on the performance drop and the efficiency drop. The tip clearance has caused specific work reduction and additional entropy generation. The former, which is called inviscid loss, is independent of any internal loss and the latter, which is called viscous loss, is dependent on every loss in the flow passage. Two components equally affected the performance drop as the tip clearances were small, while the efficiency drop was influenced by the viscous component alone. The additional entropy generation was modeled with all the kinetic energy of the tip leakage flow. Therefore, the present paper can provide how to quantitatively estimate the tip clearance effect on the performance and efficiency.
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Abbreviations
- Cp :
-
Specific heat at constant pressure
- Cθ:
-
Absolute circumferential velocity
- Cm :
-
Absolute meridional velocity
- po :
-
Total pressure
- R:
-
Universal gas constant
- To :
-
Total temperature
- W:
-
Relative velocity
- ho :
-
Total enthalpy
- \(\dot m\) :
-
Mass flow rate
- S:
-
Entropy
- t:
-
Tip clearance
- u:
-
Impeller speed
- v:
-
Velocity
- β:
-
Relative flow angle
- γ:
-
Specific heat ratio
- η:
-
Efficiency
- π:
-
Total to total pressure ratio,p 02/p01
- τ:
-
Total to total temperature ratio.T 02/T01
- ζ:
-
Viscous loss factor
- Δ:
-
Increment
- 1:
-
Impeller inlet
- 2:
-
Impeller exit
- m:
-
Meridional direction
- n:
-
Normal direction in blade
- l:
-
Leakage flow
- lm:
-
Leading edge of main blade
- tm:
-
Trailing edge of main blade
- ls:
-
Leading edge of splitter
- ts:
-
Trailing edge of splitter
- *:
-
Value for zero tip clearance
References
Choi, C. H., 1999, “Analysis of Steady and Unsteady Compressible Flows Using a Low Reynolds Numberk-w Turbulence Model,”Ph. D. Dissertation. Seoul National University, Korea.
Cumpsty, N. A., 1989,Compressor Aerodynamics, Longman Scientific & Technical.
Denton, J. D., 1993, “Loss Mechanisms in Turbomachines,”Journal of Turbomachinery, Vol. 115, pp. 621–656.
Farge, T. Z., Johnson, M. W. and Maksoud, T. M. A., 1989, “Tip Leakage in a Centrifugal Impeller,”Journal of Turbomachinery, Vol. III, pp. 224–249.
Hah, CA., 1986, “A Numerical Modeling of Endwall and Tip-Clearance Flow of an Isolated Compressor Rotor,”Journal of Engineering for Gas Turbines and Power, Vol. 108, pp. 15–21.
Ishida, M., Ueki, H. and Senoo, Y., 1990, “Effect of Blade Tip Configuration on Tip Clearance Loss of a Centrifugal Impeller,”Journal of Turbomachinery, Vol. 112, pp. 14–18.
Japikse, D. and Baines, N. C, 1994, Introduction to Turbomachinery, Concepts ETI, Inc. and Oxford University Press.
Koch, C. C. and Smith Jr.. L. H., 1976, “Loss Sources and Magnitudes in Axial-Flow Compressors,”Journal of Engineering for Power, July, pp. 411-424.
Lakshminarayana, B., 1970, “Methods of Predicting the Tip Clearance Effects in Axial Flow Turbomachines,”Journal of Basic Engineering, Vol. 92, pp. 467–482.
Lakshminarayana, B., 1996,Fluid Dynamics and Heat Transfer of Turbomachinery, John Wiley & Sons, Inc.
Larosiliere, L. M., Skoch, G. J. and Prahst, P. S., 1999, “Tip Leakage in a Centrifugal Impeller Using Computational Fluid Dynamics and Measurements,”Journal of Propulsion and Power, Vol. 15, No. 5, pp. 623–632.
Moore, J., Moore, J. G. and Timmis, P. H., 1984, “Performance Evaluation of Centrifugal Compressor Impellers Using Three-Dimensional Viscous Flow Calculations,”Journal of Engineering for Gas Turbines and Power, Vol. 106, pp. 475–481.
Myong, H. K. and Yang, S. Y., 2003, “Numerical Study on Flow Characteristics at Blade Passage and Tip Clearance in a Linear Cascade of High Performance Turbine Blade,”KSME Int- ernational Journal, Vol. 17, No. 4, pp. 606–616.
Pampreen, R. C, 1973, “Small Turbomachinery Compressor and Fan Aerodynamics,”Journal of Engineering for Power, July, pp. 251-256.
Rains, D. A., 1954, “Tip Clearance Flows in Axial Flow Compressors and Pumps,” California Institute of Technology, Hydrodynamics and Mechanical Engineering Lab., Report No. 5.
Senoo, Y. and Ishida, M., 1986, “Pressure Loss Due to the Tip Clearance of Impeller Blades in Centrifugal and Axial Blowers,”Journal of Engineering for Gas Turbines and Power, Vol. 108, pp. 32–37.
Senoo, Y. and Ishida, M., 1987, “Deterioration of Centrifugal Performance Due to Tip Clearance of Centrifugal Impellers,”Journal of Turbomachinery, Vol. 109, pp. 55–61.
Shum, Y. K. P., Tan, C. S. and Cumpsty, N. A., 2000, “Impeller-Diffuser Interaction in Centrifugal Compressor,”Journal of Turbomachinery, Vol. 122, pp. 777–786.
Storer, J. A. and Cumpsty, N. A., 1991, “Tip Leakage Flow Axial Compressor,”Journal of Turbomachinery, Vol. 113, pp. 252–259.
Whitfield, A. and Baines, N. C, 1990,Design of Radial Turbomachines, Longman Scientific & Technical.
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Eum, HJ., Kang, YS. & Kang, SH. Tip clearance effect on through-flow and performance of a centrifugal compressor. KSME International Journal 18, 979–989 (2004). https://doi.org/10.1007/BF02990870
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DOI: https://doi.org/10.1007/BF02990870