Evaluation of leakage through labyrinth seals with analytical models

• Autorzy: Szymański Artur , Dykas Sławomir

Identyfikatory

DOI

https://doi.org/10.17466/tq2019/23.1/f

• Języki publikacji: EN

Abstrakty

EN

Secondary flows in turbomachinery highly affect the overall efficiency and rotorstability. A prime example of such a phenomenon are leakage flows. Despite their complexity, they can often be estimated with simple semi-empirical formulae, solved with hand calculations.Such an approach is much more cost and time effective during the design process. The formula econsists of a carry-over coefficient and a discharge coefficient elements. To evaluate the leakage properly, an adequate model of the carry-over coefficient has to be developed. This paper presents how the flow conditions and the cavity geometry changes in a straight through labyrinth sea laffect the amount of leakage. The effect of the number of teeth, the gap size, the Reynolds number and the pressure ratio are considered. The data to validate the results was obtained from an in-house experiment, where a vast number of cases was tested. Additionally, the study was supported by a two-dimensional steady-state CFD study. Eleven analytical models, including both very simple as well as more sophisticated methods, were solved according to the experimental case and compared. Six different seal configurations were examined. They included straight through seals with two and three straight knives for various gap sizes.The comparison highlighted differences in the results for models – a certain group presented underestimated results. However, another group of models – presented an excellent agreement with the experimental data. Based on this study, a group of models representing the results within the 10% uncertainty band was selected.

Słowa kluczowe

EN

labyrinth seals; analytical methods; experiment; turbomachinery; gas turbine; validation

• Wydawca: Politechnika Gdańska
• Czasopismo: TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
• Rocznik: 2019
• Tom: Vol. 23, No 1
• Strony: 61--79
• Opis fizyczny: Bibliogr. 20 poz., rys., tab.

Twórcy

autor

Szymański Artur

• Centre for Propulsion Engineering, Cranfield University, Cranfield, Bedfordshire

autor

Dykas Sławomir

• Silesian University of Technology, Institute of Power Engineering and Turbomachiner, Konarskiego 18, 44–100 Gliwice, Poland

Bibliografia

• [1] Vennard J K and Street R L 1982 Elementary Fluid Mechanics, John Wiley & Sons, NewYork
• [2] Martin H 1908 Engineering 85 33
• [3] Childs D W 1993 Turbomachinery Rotordynamics – Phenomena, Modeling, and Analysis,John Wiley & Sons, New York
• [4] Stodola A 1924 Dampf- und Gasturbinen, Springer-Verlag
• [5] Milne-Thomson L 1974 Theoretical Hydrodynamics, 5th ed., MacMillan, London
• [6] Matthias A and Willinger R 2009 Influence of Rotation and Eccentricity on Labyrinth SealLeakage, Paper 084, ETC 8, 8th European Turbomachinery Conference, Graz, Austria
• [7] Egli A 1935 Trans.ASME 57 115
• [8] Hodkinson B 1939 Proceedings of the Institution of Mechanical Engineers 141 283
• [9] Vermes G 1961 ASMETransactions – Journal of Engineering for Power 2(83)161
• [10] Eldin A 2007 Leakage and Rotordynamic Effects of Pocket Damper Seals and See-Through Labyrinth Seals, Dissertation, Texas A&M University
• [11] Shultz R R 1996 Analytical and Experimental Investigation of a Labyrinth Seal Test Rigand Damper Seals for Turbomachinery, M. S. Thesis, Texas A&M University
• [12] Gurevich M I 1965 Theory of Jets in an Ideal Fluid, Academic Press, New York
• [13] Childs D W and Scharrer J 1988 Journal of Vibration, Acoustics, Stress and Reliabilityin Design 11 0281
• [14] Scharrer J 1988 Journal of Vibration, Acoustics, Stress and Reliability in Design 110 270
• [15] Esser D and Kazakia J Y 1995 International Journal of Engineering Science 15(33)2309
• [16] Kurohashi M, Inoue Y, Abe T and Fujikawa T 1980 Vibrations in Rotating Machinery 215
• [17] Chupp R E, Hendricks R C, Lattime S B, and Steinetz B M 2006 Sealing in Turbomachinery,NASA/TM-2006-214341, Glenn Research Centre, Cleveland
• [18] Szymanski A, Bochon K, Wróblewski W, Marugi K, Dykas S and Fraczek D 2018 Journalof Engineering for Gas Turbines and Power 140 122503 doi: 10.1115/1.4040767
• [19] Szymański A, Dykas S, Majkut M and Strozik M 2016 Transactions of the Institute of Fluid-flow Machinery 134 87
• [20] Braun E, Dullenkopf K and Bauer H J 2012 ASMEPaper GT 2012 68077