EXPERIMENTAL AND NUMERICAL STUDY ON HEAT TRANSFER PERFORMANCE OF SQUARE, CYLINDRICAL AND PLATE HEAT SINKS IN EXTERNAL TRANSITION FLOW REGIME

Yıl 2019, Cilt: 39 Sayı: 2, 151 - 161, 31.10.2019

Aykut Barış Özgür Bayer

Öz

Geometrical optimization of heat sinks with square, cylindrical and plate fins for heat transfer increase is numerically analyzed in transition regime external flow. The relations between the thermal characteristics of fins and boundary conditions such as free-stream velocity are investigated. Experimental studies are performed by using manufacturable fins to validate the numerical model. Heat transfer correlations are derived in order to determine average heat transfer coefficients over a certain range of both Reynolds number and non-dimensional geometric parameters like spanwise and streamwise spacings. Confidence level of the experimental work is demonstrated by uncertainty analysis. Cylindrical fins are observed to be approximately 4.5% superior to ones with square and plate profiles in terms of maximum base plate temperature.

Anahtar Kelimeler

CFD, external flow, fin, heat sink, transition regime, heat transfer correlation

DIŞ GEÇİŞ AKIŞI REJİMİNDE KARE, SİLİNDİR VE PLAKA ISI KUYULARI İÇİN ISI TRANSFER PERFORMANSI ÜZERİNE DENEYSEL VE SAYISAL ÇALIŞMA

Öz

Kare, silindir ve plaka kanatçıklı ısı kuyularının ısı transferi artışına yönelik geometrik en iyileştirilmeleri geçiş rejimindeki dış akışta sayısal olarak incelenmiştir. Serbest akış hızı gibi sınır koşulları ile kanatçık termal karakterizasyonu arasındaki ilişkiler araştırılmıştır. Sayısal modeli doğrulamak için üretilebilir kanatçıklar kullanılarak deneysel çalışmalar gerçekleştirilmiştir. Ortalama ısı transfer katsayısını belirlemek üzere, hem belirli bir Reynolds sayısı hem de akış yönü ile akışa dik doğrultudaki boyutsuz geometrik parametrelerin aralığı dikkate alınarak ısı transferi korelasyonları elde edilmiştir. Deneysel çalışmanın güvenilirliği belirsizlik analizi ile gösterilmiştir. Taban plakası en yüksek sıcaklığının, silindir kanatçıklı ısı kuyusunda diğerlerine göre yaklaşık %4.5 oranında daha düşük çıktığı gözlemlenmiştir.

Anahtar Kelimeler

HAD, Dış Akış, Kanatçık, Isı Kuyusu, Geçiş Rejimi, Isı Transfer Korelasyonu

Kaynakça

• A-Damook, A., Summers, J. L., Kapur, N. and Thompson, H., 2016, Effect of Temperature-Dependent Air Properties on the Accuracy of Numerical Simulations of Thermal Airflows over Pinned Heat Sinks, Int. Communications in Heat and Mass Transfer, 78, 163-167.
• Ayli, E., Bayer, O. and S. Aradag, 2016, Experimental Investigation and CFD Analysis of Rectangular Profile Fins in a Square Channel for Forced Convection Regimes, Int. J. Therm. Sci., 109, 279-290.
• Babus’Haq, R. F., Akintunde, K. and Probert, S. D., 1995, Thermal Performance of a Pin-Fin Assembly, Int. J. Heat Fluid Flow. 16, 50-55.
• Culham, J. R. and Muzychka, Y. S., 2001, Optimization of Plate Fin Heat Sinks Using Entropy Generation Minimization, IEEE Trans. Components Packag. Technol., 24, 159-165.
• Chapra, S. C. and Canale, R. P., 2015, Numerical Methods for Engineers, (7th Ed.) McGraw-Hill, New York.
• Chu, P., He, Y. L., Xu, R. J. and Han, H., 2011, Experimental and Numerical Study on Natural Air Cooling of a Remote Radio Unit, Journal of Enhanced Heat Transfer, 18, 345-359.
• Deshmukh, P.A., 2013, Comparison of Thermal Performance of Circular and Elliptical Pin Fin Heat Sinks in Assisting Mixed Convection, IEEE, 50, 178-184.
• Diani, A., Mancin, S., Zilio, C. and Rossetto, L., 2013, An Assessment on Air Forced Convection on Extended Surfaces: Experimental Results and Numerical Modeling, Int. J. Therm. Sci., 67, 120-134.
• Dong, J., Chen, J., Zhang, W. and J. Hu, 2010, Experimental and Numerical Investigation of Thermal-Hydraulic Performance in Wavy Fin-and-Flat Tube Heat Exchangers, Appl. Therm. Eng., 30, 1377-1386.
• Electronic Temperature Instruments, Emissivity Table, accessed February 12, 2018 from https://thermometer.co.uk/img/documents/emissivity_table.pdf.
• European Association of National Metrology Institutes, Calibration Guidelines, accessed December 29, 2018, from https://www.euramet.org/publications-media- centre/ calibration-guidelines/.
• Incropera, F. P. and Dewitt, D. P., Bergman, T. L., Lavine, A. S., 2013, Introduction to Heat Transfer (7th Ed.), John Wiley & Sons Inc, Singapore.
• Jonsson, H. and Moshfegh, B., 2001, Modeling of the Thermal and Hydraulic Performance of Plate Fin, Strip Fin, and Pin Fin Heat Sinks-Influence of Flow Bypass, IEEE Trans. Components Packag. Technol., 24, 142-149.
• Jubran, B. A., Hamdan M. A. and Abdullah, R. M., 1993, Enhanced Heat Transfer, Missing Pin, and Optimization for Cylindrical Pin Fin Arrays, Journal of Heat Transfer, 115, 576-583.
• Kanargi, B., Lee, P. S. and Yap, C., 2018, A Numerical and Experimental Investigation of Heat Transfer and Fluid Flow Characteristics of an Air-Cooled Oblique-Finned Heat Sink, Int. J. of Heat and Mass Transfer, 116, 393-416.
• Khan, W. A., 2004, Modeling of Fluid Flow and Heat Transfer for Optimization of Pin-Fin Heat Sinks, PhD Thesis, University of Waterloo.
• Kwak, D-B., Noh, J-H., Lee, K-S. And Yook, S-J., 2017, Cooling Performance of a Radial Heat Sink with Triangular Fins on a Circular Base at Various Installation Angles, Int. J. of Thermal Science, 120, 377-385.
• Mentor Graphics, FloEFD Technical Reference V14, Oregon: Mentor Graphics Corporation, pp. 238, 2015a.
• Mentor Graphics, Solving Engineering Problems, Oregon: Mentor Graphics Corporation, p. 98, 2015b.
• MIT, Turbulence Modeling, accessed February 12, 2018 from http://web.mit.edu/cuongng/www/Site/Publication _files/TurbulenceModeling_04NOV05.pdf.
• Moffat, R. J., 1998, Describing the Uncertainties in Experimental Results, Exp. Therm. Fluid Sci., 1, 3-17.
• Mohammadian, S.K. and Zang, Y., 2015, Thermal Management Optimization of an Air-Cooled Li-Ion Battery Module Using Pin-Fin Heat Sinks for Hybrid Electric Vehicles, Journal of Power Sources, 273, 431-439.
• OPTRIS, Datasheet Pi 640, accessed February 12, 2018 from http://www.optris.com.tr/infrared-cameras.
• Sahiti, N., Lemouedda, A., Stojkovic, D., Durst, F. and Franz, E., 2006, Performance Comparison of Pin Fin in-Duct Flow Arrays with Various Pin Cross-Sections, Appl. Therm. Eng., 26, 1176-1192.
• Samarth, A. B. and Sawankar, K. S., 2014, Thermal Performance of Perforated Pin-Fin Arrays in Staggered Arrangement, International Journal of Scientific & Engineering Research, 5, 777-783.
• Sandhu, H., Gangacharyulu, D., and Singh, M. K., 2014, Experimental Investigations on the Cooling Performance of Microchannels Using Alumina Nanofluids with Different Base Fluids”, Journal of Enhanced Heat Transfer, 25, 283-291.
• Tahat, M., Kodah, Z. H., Jarrah, B. A. and Probert, S. D., 2000, Heat Transfers from Pin-Fin Arrays Experiencing Forced Convection, Applied Energy, 67, 419-442.
• Yang, K. S., Chu, W. H., Chen, I. Y. and Wang, C. C., 2007, A Comparative Study of the Airside Performance of Heat Sinks Having Pin Fin Configurations, Int. J. Heat Mass Transf., 50, 4661-4667.
• Yang, Y. T., Peng, H. S. and Hsu, H. T., 2013, Numerical Optimization of Pin-Fin Heat Sink with Forced Cooling, International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering, 7, 884-891.
• Yuan, W., Zhao, J., Tso, C. P., Wu, T., Liu W. and T. Ming, 2012, Numerical Simulation of the Thermal Hydraulic Performance of a Plate Pin Fin Heat Sink, Appl. Therm. Eng., 48, 81-88.
• Zukauskas, A., 1972, Heat Transfer From Tubes in Crossflow, Vilnius: Academy