GEMİ PERVANELERİNDE KAVİTASYON KAYNAKLI GÜRÜLTÜ VE FARKLI İZ ALANLARININ PERVANE PERFORMANSINA ETKİSİNİN İNCELENMESİ

Gemi pervanelerinde, pervaneye gelen akım alanının ünifom olmaması (iz dağılımının düzensiz olması) ve pervane kanatlarında oluşması muhtemel olan kavitasyon olgusunun meydana istenmeyen etkiler (performans kaybı, erozyon, titreşim, gürültü ) meydana getirebilmektedir. Özellikle, pervane kanatları üzerinde oluşan tabaka kavitasyonu büyüklüğünün periyodik olarak değişmesi, daimi olmayan pervane kuvvetlerine ve titreşime, su altında ve gemi bünyesinde ise gürültü oluşumuna sebebiyet vermektedir. Bu çalışmada, geometrisi belli olan ve verilen çalışma koşulları altında kavitasyon gösteren bir gemi pervanesinin tabaka kavitasyonu kaynaklı gürültü tahmini öngörülmüştür. Ayrıca beş farklı gemi arkası iz dağılımının, ele alınan pervanenin performansına, pervane kanadının bir tam devrindeki itme değerlerine ve pervane tarafından gemi üzerindeki bir noktada oluşturulan basınç değişimlerine olan etkisi karakteristiklerinden biri olan çalıklık değeri değiştirilerek (iki farklı çalıklık açısı), bu özelliğin kavitasyon kaynaklı gürültü üzerine olan etkisi parametrik olarak analiz edilmiştir. Aynı zamanda sadece orjinal olan pervane, performans açısından incelenmiştir. Yapılan hesaplamalarda, kaldırıcı yüzey teorisine (lifting surface method) dayalı olan ve gürültü öngörüsü için geliştirilmiş Brown yöntemini kullanan sayısal bir yöntemden yararlanılmıştır. Elde edilen gürültü seviyeleri literatürde yer alan diğer gürültü öngörü yaklaşımları ile karşılaştırılmıştır. İz dağılımının düzensiz olduğu durumlarda çalıklığın etkin bir özellik olarak öne çıktığı görülmüş ve bu çalışma koşullarındaki pervanenin çalıklığı arttırılarak, titreşim ve gürültünün önemli seviyelerde azaltılabileceği sonucuna varılmıştır

Anahtar Kelimeler:

Gemi pervanesi, Kaldırıcı Yüzey Yöntemi, Kavitasyon, Gürültü, İz

INVESTIGATION OF CAVITATION INDUCED NOISE AND EFFECTS ON PERFORMANCE OF DIFFERENT WAKE FIELDS IN MARINE PROPELLERS

The fact that the inflow to the marine propeller is not uniform and cavitation phenomenon which is likely to develop on propeller blades may lead to undesirable effects (performance loss, erosion, vibration, and noise) with respect to hydrodynamic performance. Particularly, periodically changing of the sheet cavitation size on the propeller blades leads to unsteady propeller force, vibration, underwater radiated noise as well as noise in the ship. In this study, prediction of sheet cavitation induced noise of a marine propeller whose geometry and wake distribution are known, were examined. Cavitation was present in all given operating conditions. Further investigations were carried out for the target propeller to observe the effect of five different wake distributions on propeller performance, thrust values on the propeller blade for one rotation, and changing of propeller induced pressure pulse at a point on the hull. By changing skew value (two different skew angle), which is one of the geometric characteristics of original propeller, the effect on the cavitation induced noise was analyzed parametrically. The current study includes a discussion for only the original propeller in terms of performance (thrust, torque and efficiency). A numerical approach, based on Brown’s method and lifting surface method, was used to predict noise calculations. Noise levels obtained from calculations were compared to the other noise predictions in literature. It can be seen that skew has an effect in cases where the inflow is non-uniform. It can be concluded that vibration and noise levels can be reduced significantly by increasing the skew value of the propeller in these operating conditions

Keywords:

Marine propeller, Lifting Surface Method, Cavitation, Noise, Wake,

PDF

___

Bal, S.. 2008. Kavitasyon Yapan Gemi Pervanesinin Karakteristiklerinin Yöntem ile İncelenmesi, Gemi İnşaatı ve Deniz Teknolojisi Teknik Kongresi, Cilt1,s. 239-249,
Bir [2] Bal, S.. 2010. Gemi Pervanelerinin Hidrodinamik Tersane, Gemi İnşa Sektörü ve Yan Sanayisi Dergisi, Cilt.17, s. 32-36.
Fine, N. and Kinnas, S.A. 1993b.The Nonlinear Numerical Prediction of Unsteady Propellers of Extreme Geometry, Proceedings:
Conference on Numerical Ship Hydrodynamics, August, s. 531-544.
Kim, Y.-G. and Lee, C.-S. 1996. Prediction of Unsteady Performance of Marine Propellers with Cavitation Using
Proceedings, 21st Symposium on Naval Hydrodynamics, Trondheim, Norway,s.913-928
Method, [5] Kinnas, S.A., Lee,H. and Young, Y.L. 2002. Boundary Element Techniques for the Prediction of Sheet and Developed Tip Vortex Cavitation, Electronic
Elements, Cilt.BETEQ2001, sayı.2, s.151-178
Boundary [6] Kinnas, S.A., Lee, H. and Young, Y.L. 2003. Modeling of Unsteady Sheet Cavitation
Propellers,International Journal of Rotating Machinery, Cilt 9 (4), s. 263- 277.DOI:10.1080/102362103902030 08
Marine [7] Kulczyk, J. S.,Skraburskı, L. and Zawıslak, M. 2007 Analysis of Screw Propeller DTMB 4119 using the FLUENT System, Archives of Civil and Mechanical Engineering, Cilt.7(4) s.129-136
Okamura, N. and Asano, T., 1988.Prediction Cavitation Noise and Its Comparison with Journal of the Society of Naval Architects of Japan, Cilt 164, s.19-33, December Propeller Full-Scale
Measurements, [9] Salvatore, F. and Ianıiello, S., Preliminary Results on Acoustic Modelling of Cavitating Propellers, International
Boundary Element Methods, IABEM 2002, UT Austin, TX, May 28-30
for [10] Lee, H., ve Kinnas, S.A.. 2005 A BEM for the Modeling of Propeller Sheet Cavitation Inside a Cavitation Tunnel, Journal of Computational Mechanics, Cilt.37(1):,s.41-51.DOI
1007/s00466-005-0696-z
Seol, H., Suh, J.C. and Lee, S. 2005 Development of Hybrid Method for the Propeller Noise, Journal of Sound and Vibration, Cilt.288, s.345-360.DOI: 10.1016/j.jsv.2005.01.015
Cheolsoo P., Hanshin S., Kwangsoo K. and Woojae S. 2009.A Study on Propeller Noise Source Localization in a
Engineering, Cilt.36 (9-10): s.754- 762.DOI:10.1016/j.oceaneng.2009.04. 005
Ocean [13] Testa, C., Salvatore, F., Ianniello, S. and Gennaretti, M. 2005. Theoretical and
Hydroacoustic Applications of the Issues for 11th
AIAA/CEAS [14] Odabaşı, A.Y. 1987. Cavitation Inception and Prediction of Broad- Band Noise Levels, British Maritime Technology, Tech.Rep.W1607, March [15] Fraser,A., J. 1986.State of the Art in Noise,
Prediction and Minimisation of Propeller Induced Waterborne Noise, British Maritime Technology Limited, Hydromechanics Computational Dept., February Part
:The Division, Hydromechanics [16] Atlar, M., Takinaci, A., C.and Korkut, CAV 2001.Cavitation Tunnel Tests for Propeller Noise of a FRV and Comparisons Measurements, s.1-13.
Full-Scale [17] Takinaci, A., C. and Taralp, T. 2012. Prediction
Broadband Propeller Noise, Journal of Marine Science and Technology, Cilt. 21(5), s.538-544. DOI: 10.6119/JMST- 012-0831-1
of [18] Vassenden, J.and Lovik, A. 1978. Basic and Applied Aspects of Scaling Cavitation Noise, The Ship Research Instıtute of Norway, December, Trondheim, Norway
Aktaş, B., Türkmen, S.,Korkut, E., Fitzsimmons, P. and Atlar, M. 2014.Systematic Cavitation Tunnel Tests of a Propeller in Uniform and Inclined Flow Conditions as Part of a Round Robin Test Campaign, A. Yücel Odabaşı Colloquium Series 1st International Meeting - Propeller Noise & Vibration 6th – 7th November İstanbul, Türkiye.
Özden, M., C., Gürkan, A., Y., Özden, Y., A., Canyurt, T. G. and Korkut, E. 2014. Underwater Radiated Noise Prediction for a Submarine Propeller in Different Flow Conditions, A. Yücel Odabaşı Colloquium Series 1st International Meeting - Propeller Noise & Vibration 6th – 7th November İstanbul, Türkiye.
Szantyr J.A.2008. The Crucial Contemporary Problems of The Computational Methods for Ship Propulsor Hydrodynamics, Gdańsk University of Technology,Archives Of Civil and Mechanical Engineering, VIII (1), Gdańsk University of Technology, Poland
Wittekind, D. ve Schuster, M. 2014. Propeller Cavitation Noise and Background Noise in the Sea, A. Yücel Odabaşı Colloquium Series 1st International Meeting - Propeller Noise & Vibration 6th – 7th November İstanbul, Türkiye.
Kowalczyk, S. ve Hoffmann, P. 2014. Propeller Noise Investigations by Means of Middle Size Cavitation Tunnel Measurements, A. Yücel Odabaşı Colloquium Series 1st International Meeting - Propeller Noise & Vibration 6th – 7th November İstanbul, Türkiye.
Ghassemı, H. 2009. The Effect of Wake Flow and Skew Angle on the Ship Propeller Performance, Scıentıa Iranıca Transactıon B-Mechanıcal Engıneerıng, Cilt.16( 2), s.149-158
Abramowski, T. et al. 2010. Numerical analysis of effect of asymmetric stern of ship on its screw propeller efficiency, Polish Maritime Research, Cilt.17(4), s. DOI:13-16. 10.2478/v10012-010-0030-3
Szantyr, J.A. 1994 A method for analysis propellers in non-uniform flow, International Shipbuilding Progress, Cilt.41(427, s.223-242.
marine [27] Yoshımura, Y. ve Koyanagı, Y. 2004. Design of a Small Fisheries Research Vessel with Low Level of Underwater- Radiated Noise, Journal of the Marine Acoustic Society of Japan, Cilt. 31 (3): s.1-9.