Sıkıştırma ile Ateşlemeli Bir Motorun Genişleme Zamanında Kompresyon Segman Yuvası Boşluğunun Akış Karakteristiklerinin İncelenmesi

Öz

Pistonlu motorların güç strokunda, yanma sonu oluşan basıncın kayıpsız olarak piston yüzeyine etkimesi istenir. Ancak yaşanan kayıplardan bir tanesi segman yuvalarındaki ve boşluklarındaki basınç kayıplarıdır. Bu çalışmada, Renault F8Q706 motorunun tepe kompresyon segmanı boşluğunun akış özellikleri incelenmiştir. İncelemeler, Hesaplamalı Akışkanlar Dinamiği (HAD) analizi kullanılarak 2500 d/dk'de, tam yükte ve üst ölü noktadan 15° krank mili açısı sonrasındaki güç strokunda yapılmıştır. Akışkan olarak yanma sonu ürünleri kullanılmıştır. Öncelikle 1-Boyutlu (1B) motor modeli oluşturulmuş ve literatür testleri ile doğrulanmıştır. 1B modelden alınan silindir içi karakteristikler 2-Boyutlu (2B) HAD modelinde tanımlanmıştır. Sonuçta, 6,5MPa, 5MPa, 3MPa giriş basınçlarında, kaçak debiler sırasıyla 2,97E-05, 1,66E-05, 3,41E-6 kg/s olarak hesaplanmıştır. 6,5 MPa giriş basıncı için, segman boşluğunda oluşan basınç kayıpları sonunda net basınç 6.49941 MPa olarak hesaplanmıştır.

Anahtar Kelimeler

• HAD
• Segman
• Sızdırmazlık

Investigation of the Flow Characteristics of the Compression Ring Groove Cavity in the Expansion Time of a Compression Ignition Engine

Öz

In the expansion stroke of reciprocating engines, it is desired that the pressure generated after combustion acts on the piston surface without any losses. However, there are some losses during this process. One of these is the pressure losses in the ring grooves and gaps. In this study, the flow characteristics of the peak compression ring gaps of the Renault F8Q706 engine were examined. Investigations were carried out using Computational Fluid Dynamics (CFD) at 2500 rpm, full load and at the beginning of the piston expansion stroke after a crankshaft angle of 15 from the top dead center. Combustion products were used as fluids in the investigations. In the study, firstly, a 1D engine model was created and verified with the same engine tests in the literature. In-cylinder characteristics taken from the 1D model are defined as boundary conditions in 2-Dimensional (2D) CFD analyses. As a result, in response to the ring cavity inlet pressures of 6.5MPa, 5MPa, 3MPa, the leakage flow rates in the cavity were calculated as 2.97E-05, 1.66E-05, 3.41E-6 kg/s, respectively. For 6.5 MPa inlet pressure, the net pressure was calculated as 6.49941 MPa as a result of the pressure losses in the ring gap.

Anahtar Kelimeler

• CFD
• piston Ring
• Sealing

Kaynakça

1. Türkiye Cumhuriyeti Dışişleri Bakanlığı. (2016). Paris Anlaşması Metni. https://www.mfa.gov.tr/paris-anlasmasi.tr.mfa, (12.12.2023).
2. Türkiye İstatistik Kurumu (TÜİK). (2024). Motorlu Taşıt İstatistikleri. https://l24.im/FZoQ, (07.01.2024)
3. Aktaş, F. (2022). Spark ignition timing effects on a converted diesel engine using natural gas: a numerical study. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 236, 1949-63.
4. Aktaş, F. (2022). Numerical investigation of equivalence ratio effects on a converted diesel engine using natural gas. Journal of Energy Resources Technology. 144, 092305.
5. Ertugrul, I., Ulkır, O., Ozer, S., Ozel, S. (2022). Analysis of thermal barrier coated pistons in the COMSOL and the effects of their use with water + ethanol doped biodiesel. Thermal Science. 26(4A), 2981-2989.
6. Mohamed, E. S. (2018). Performance analysis and condition monitoring of ICE piston-ring based on combustion and thermal characteristics. Applied Thermal Engineering. 132, 824-840.
7. Hernández-Comas, B., Maestre-Cambronel, D., Pardo-García, C., Fonseca-Vigoya, MDS., Pabón-León, J. (2021). Influence of compression rings on the dynamic characteristics and sealing capacity of the combustion chamber in diesel engines. Lubricants. 9(3), 25.
8. Orozco Lozano, W., Fonseca-Vigoya, MDS., Pabón-León, J. (2021). Study of the kinematics and dynamics of the ring pack of a diesel engine by means of the construction of CFD model in conjunction with mathematical models. Lubricants. 9(12), 116.

9. Koszalka, G. (2019). The use of the gas flow model to improve the design of the piston-rings-cylinder system of a diesel engine. IOP Conference Series: Materials Science and Engineering. 659, 012072.
10. Yeşilada, Ö. (1997). Piston Rings. (M.Sc.), Istanbul Technical University, Institute of Science, Department of Mechanical Engineering, Istanbul, Türkiye.
11. Chucholowski C, Kornprobst H, Zellinger K. (1982). FVV. Absclußbericht Nr. 250.
12. Kornprobst H, Zellinger K. Bewegung, R. (1987). FVV. Abschlußbericht Nr. 344.
13. Furuhama, S. (1959). A dynamic theory of Piston-Ring lubrication: 1st report, calculation, Bull JSME, 2, 423-428.
14. Karamangil, M. E. (2004). Benzinli motorlarda segman ve conta boşluğu hidrokarbonlarının silindir içi dağılımı, Uludağ Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi, 9(1), 53-64.
15. Lyubarskyy, P., Bartel, D. (2016). 2D CFD-model of the piston assembly in a diesel engine for the analysis of piston ring dynamics, mass transport and friction, Tribology International, 104, 352-368.
16. Satge´ de Caro, P., Mouloungui, Z., Vaitilingom, G., Berge, J. C. (2001). Interest of combining an additive with diesel–ethanol blends for use in diesel engines. Fuel. 80(4), 565-574.
17. Woschni, G. (1967). A universally applicable equation for the instantaneous heat transfer coefficient in the internal combustion engine. SAE Int. J. Engines.
18. Ghojel, J. I. (2010). Review of the development and applications of the wiebe function: a tribute to the contribution of Ivan Wiebe to engine research. International Journal of Engine Research. 11(4), 297-312.
19. Wiebe, I. (1956). Semi-empirical expression for combustion rate in engines. InProceedings of Conference on Piston Engines.
20. Newhall, H. K. (1969). Kinetics of engine-generated nitrogen oxides and carbon monoxide. Symposium (International) on Combustion. 12(1), 603-613.
21. Cheng, W. K., Hamrin, D., Heywood, J. B., Hochgreb, S., Min, K., Norris, M. (1993). An overview of hydrocarbon emissions mechanisms in spark-ignition engines. SAE Int. J. Engines.
22. Fenimore, C. P. (1971). Formation of nitric oxide in premixed hydrocarbon flames. Symposium (International) on Combustion. 13(1), 373-380.
23. Pipitone, E. (2009). A new simple friction model for s. i. engine. SAE Technical Paper.
24. Özer, S. (2014). Alkollerin içten yanmalı motorlarda alternatif yakıt olarak kullanılması. Uludağ Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi, 19(1), 97-114.
25. Aktaş, F. (2021). Numerical investigation of the effects of the use of propane-diesel as a dual fuel in a diesel engine on the combustion regime, engine performance and emission values. (PhD), Gazi University, Ankara, Türkiye.
26. Heywood, J. B. (1988). Internal Combustion Engine Fundamentals. McGraw-Hill.
27. Mahle GmbH. (2012). Pistons And Engine Testing (1st ed). Vieweg – Teubner.
28. Winterbone, D. E., Turan, A. (2015). Advanced Thermodynamics For Engineers (2nd ed). Butterworth-Heinemann an Imprint of Elsevier.
29. Engine catalog. (2021). https://mymotorlist.com/engines/renault/, (12.12.2023).