İlhan Volkan ÖNER

Dikdörtgen Kesitli Bir Kanal İçerisinde Farklı Açılara Sahip Altıgen Kanatçıklı Yüzeylerde Hız ve Sıcaklık Dağılımının Nümerik Olarak İncelenmesi

Isınan yüzeylere kanatçık ilavesi ile ısı çekilerek yüzeyin soğutulması işlemi birçok sistem için yaygın olarak kullanılmaktadır. Kanatçıklar ısı transfer yüzey alanlarını arttırarak ısı transferinin iyileşmesini sağlanmaktadırlar. Bu çalışmada, dikdörtgen bir kanal içine aynı yüzey alanına sahip, aynı dizilimde 0°, 15° ve 30° farklı açılarla yerleştirilen altıgen şeklindeki kanatçıkların üzerinden sabit sıcaklık ve sabit Reynolds sayılarında akan iş akışkanı havanın hız ve sıcaklık dağılımları Ansys Fluent paket programı kullanılarak numerik olarak analiz edilmiştir. Yapılan analizler 15° dizileme sahip kanatçıklarda, sınır tabakanın yenilenmesinden ve kanatçıklar arasında oluşan türbülanstan dolayı ısı transfer katsayısının iyileştiği sonucuna varılmıştır. Hesaplamalı akışkanlar dinamiği (CFD) analizi, Ansys Fluent paket program ile gerçekleştirilmiştir. Çalışmadan elde edilen sonuçlarda tüm kanatçık açılarında (0° ,15° ve 30°) basınç düşümü, sıcaklık ve hız dağılımları gösterilmiştir.

Anahtar Kelimeler:

Ansys-Fluent, CFD, Isı transferi, Kanatçık dizilim açısı

A numerical investigation of velocity and temperature distribution on a heat sink with hexagonal fins facing at different angles in a rectangular duct

The cooling of hot surfaces through drawing heat by means of fins attached to the surface is widely used technique in many systems. The fins increase the heat transfer surface area, thereby improving the heat transfer. In this study, the velocity and temperature distributions of the working fluid, air, flowing at constant temperature and constant Reynolds numbers over the hexagonal fins, placed in a rectangular duct, having the same surface area and same arrangement but facing at different angles to the flow plane; 0°, 15° and 30°, were analyzed numerically. Computational fluid dynamics (CFD) analysis was carried out with Ansys Fluent. The results were obtained for pressure drop, temperature and velocity distributions at all angles (0°, 15° and 30°). As a result of the analyses performed, 15° facing angle was concluded to be the best by the virtue of the fact that the heat transfer coefficient was improved by the renewal of the boundary layer and by the turbulence occurred between the fins.

Keywords:

Ansys-Fluent, CFD, Fin facing angle, Heat transfer,

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Acharya, S., Dutta, S., Myrum, T. and Baker, R. (1993). Periodically developed flow and heat transfer in a ribbed duct. International Journal of Heat and Mass Transfer, 36(8), 2069-2082. doi:https://doi.org/10.1016/S0017-9310(05)80138-3.
Adhikari, R., Wood, D. and Pahlevani, M. (2020). Optimizing rectangular fins for natural convection cooling using cfd. Thermal Science and Engineering Progress, 17, 100484. doi:https://doi.org/10.1016/j.tsep.2020.100484.
Ahmadian-Elmi, M., Mashayekhi, A., Nourazar, S. and Vafai, K. (2021). A comprehensive study on parametric optimization of the pin-fin heat sink to improve its thermal and hydraulic characteristics. International Journal of Heat and Mass Transfer, 180, 121797. doi:https://doi.org/10.1016/j.ijheatmasstransfer.2021.121797.
Briggs, D. and London, A. L. (1960). The heat transfer and flow friction characteristics of five offset rectangular and six plain triangular plate-fin heat transfer surfaces. Technical report no. 49. Stanford Univ., Calif.: https://www.osti.gov/biblio/4068664.
Buyruk, E. ve Karabulut, K. (2017). Plakalı kanatçıklı isı değiştiricilerde kanat geometrisinin isı transferine olan etkisinin üç boyutlu sayısal olarak İncelenmesi. Dokuz Eylül Üniversitesi Mühendislik Fakültesi Fen ve Mühendislik Dergisi, 19(56), 346-363. doi:https://doi.org/10.21605/cukurovaummfd.310051.
Garg, V. K. and Maji, P. (1988). Laminar flow and heat transfer in a periodically converging‐diverging channel. International journal for numerical methods in fluids, 8(5), 579-597. doi:https://doi.org/10.1002/fld.1650080506.
Hung, S.C., Huang, S.C. and Liu, Y.H. (2019). Effect of nonuniform pin size on heat transfer in a rotating rectangular channel with pin-fin arrays. Applied Thermal Engineering, 163, 114393. doi:https://doi.org/10.1016/j.applthermaleng.2019.114393.
Karabulut, K., Buyruk, E., Kılınç, F. and Karabulut, Ö. O. (2013). Farklı geometrilerden oluşan kanatçıklı plakalı isı değiştiricileri için isı transferinin üç boyutlu sayısal olarak İncelenmesi, 11. Ulusal Tesisat Müh. Kongresi, 17-20.
Kays, W. M. and London, A. L. (1954). Compact heat exchangers--a summary of basic heat transfer and flow friction design data. To 6, Technical report no. 23. Stanford Univ., Calif.: https://www.osti.gov/biblio/4380526.
Kotcioglu, İ. and Bolukbasi, A. (2003). Experimental investigation heat transfer in different winglet-surfaces in a vertical rectangular duct. Dokuz Eylul University, Faculty of Engineering, Journal of Science and Engineering, 5(2), 89-102.
Kotçioğlu, İ., Ayhan, T., Olgun, H. and Ayhan, B. (1998). Heat transfer and flow structure in a rectangular channel with wing-type vortex generator. Turkish Journal of Engineering and Environmental Sciences, 22(3), 185-196.
Lee, C. and Abdel-Moneim, S. (2001). Computational analysis of heat transfer in turbulent flow past a horizontal surface with two-dimensional ribs. International Communications in Heat and Mass Transfer, 28(2), 161-170. doi:https://doi.org/10.1016/S0735-1933(01)00223-8.
Masao, F., Yu, S. and Goro, Y. (1988). Heat transfer and pressure drop of perforated surface heat exchanger with passage enlargement and contraction. International Journal of Heat and Mass Transfer, 31(1), 135-142. doi:https://doi.org/10.1016/0017-9310(88)90230-X.
Maughan, J. and Incropera, F. (1991). Use of vortex generators and ribs for heat transfer enhancement at the top surface of a uniformly heated horizontal channel with mixed convection flow. Journal of Heat Transfer - Transactions of The ASME, 113(2), 504-507. doi:https://doi.org/10.1115/1.2910592.
Mesler, R. (1993). Surface roughness and its effects on the heat transfer mechanism of spray cooling. Journal of Heat Transfer-Transactions of The ASME, 115(4), 1083-1083. doi:https://doi.org/10.1115/1.2911248.
Russell, A. M. and Lee, K. L. (2005). Structure-property relations in nonferrous metals (Vol. 302): Wiley Online Library.
Soleymani, Z., Rahimi, M., Gorzin, M. and Pahamli, Y. (2020). Performance analysis of hotspot using geometrical and operational parameters of a microchannel pin-fin hybrid heat sink. International Journal of Heat and Mass Transfer, 159, 120141. doi:https://doi.org/10.1016/j.ijheatmasstransfer.2020.120141.
Souza Mendes, P. and Sparrow, E. (1984). Periodically converging-diverging tubes and their turbulent heat transfer, pressure drop, fluid flow, and enhancement characteristics. Journal Heat Trasnfer, 106(1), 55-63. doi:https://doi.org/10.1115/1.3246659.
Sundén, B. (1999). Heat transfer and fluid flow in rib-roughened rectangular ducts. In Heat transfer enhancement of heat exchangers (pp. 123-140): Springer.
Tauscher, R. and Mayinger, F. (1999). Heat transfer enhancement in a plate heat exchanger with rib-roughened surfaces. In Heat transfer enhancement of heat exchangers (pp. 207-221): Springer.
Wang, Y. Q., Dong, Q.W., Liu, M.S. and Wang, D. (2009). Numerical study on plate‐fin heat exchangers with plain fins and serrated fins at low reynolds number. Chemical Engineering & Technology: Industrial Chemistry‐Plant Equipment‐Process Engineering‐Biotechnology, 32(8), 1219-1226. doi:https://doi.org/10.1002/ceat.200900079.
Wen, J., Li, K., Zhang, X., Wang, C., Wang, S. and Tu, J. (2018). Optimization investigation on configuration parameters of serrated fin in plate-fin heat exchanger based on fluid structure interaction analysis. International Journal of Heat and Mass Transfer, 119, 282-294. doi:https://doi.org/10.1016/j.ijheatmasstransfer.2017.11.058.
Wen, J., Yang, H., Tong, X., Li, K., Wang, S. and Li, Y. (2016). Optimization investigation on configuration parameters of serrated fin in plate-fin heat exchanger using genetic algorithm. International Journal of Thermal Sciences, 101, 116-125. doi:https://doi.org/10.1016/j.ijthermalsci.2015.10.024