MİKRO PİM TİPİ KANATÇIKLI VE MİKRO OYUKLU ISI ALICIDA DOYMUŞ KAYNAMALI AKIŞIN DENEYSEL İNCELENMESİ

Year 2023, Volume: 11 Issue: 1, 103 - 123, 01.03.2023

Burak Markal , Beyzanur Kul

https://doi.org/10.36306/konjes.1136042

Abstract

Mikrokanallarda kaynamalı akış, hava araçlarındaki yüksek kapasiteli elektronik sistemler, bilgisayar işlemcileri ve elektrikli araç bataryaları gibi yüksek yoğunluklu atık ısının açığa çıktığı sistemlerde, sürdürülebilirlik ve güvenli çalışma koşulları için gerekli olan soğutma çözümlerini sunma potansiyeline sahip popüler bir ısıl kontrol tekniğidir. Bu makalede, farklı kütle (136 ve 250 kg m-2 s-1) ve ısı akısı (132 – 272 kW m-2) değerlerinde deiyonize suyun kademeli olarak genişleyen akış kesitine ve yapay kabarcıklaşma oyuklarına sahip mikro pim tipi kanatçıklı ısı alıcıda (modifiye edilmiş ısı alıcı, MIA) doymuş kaynamalı akışı deneysel olarak incelenmiştir. Sonuçlar düz duvarlı paralel mikro kanallı ısı alıcı (konvansiyonel ısı alıcı, KIA) üzerinden karşılaştırmalı olarak sunulmuştur. İş akışkanının giriş sıcaklığı yaklaşık 75ºC’da sabit tutulmuştur. Yüksek hızlı kamera ile akış görüntüleri alınmış (1000 fps) ve fiziksel mekanizma görüntülerle desteklenerek irdelenmiştir. MIA’da, KIA’ya kıyasla, iki fazlı ısı transfer katsayısında %827.2’ye kadar artış sağlanmış ve kaynama kararsızlıkları etkin bir şekilde bastırılabilmiştir. Isı transferindeki iyileşmeye karşı, basınç düşümünde %50.5’e kadar artış olmuştur. Genel karakter olarak, her iki ısı alıcısında da kütle akısının basınç düşümü üzerindeki etkisi görece ihmal edilebilir düzeyde olup, artan kütle akısı ile ısı transfer katsayıları azalmaktadır. MIA’ya ait sonuçlar, KIA’ya kıyasla, kütle akısındaki değişimden görece daha çok etkilenmektedir.

Keywords

Kaynamalı akış, Mikrokanal, Yapay kabarcıklaşma odakları, Kesit genişlemesi

Supporting Institution

Türkiye Bilimsel ve Teknolojik Araştırma Kurumu (TÜBİTAK)

Project Number

219M142

Thanks

Bu makale/çalışma 219M142 nolu proje kapsamında Türkiye Bilimsel ve Teknolojik Araştırma Kurumu tarafından desteklenmiştir.

Experimental Investigation of Saturated Flow Boiling Characteristics in Micro Pin Fin and Micro Cavitied Heat Sinks

Abstract

Flow boiling in microchannels is a popular thermal management technique with the potential to provide cooling solutions required for sustainability and safe operating conditions in systems where high-density waste heat is released, such as high-capacity electronic systems in aircrafts, processors of computers, and batteries of electric vehicles. In the present paper, saturated flow boiling of deionized water in a heat sink having gradually expanding flow passage and artificial nucleation sites (modified heat sink, MIA) was experimentally investigated at different mass (136 and 250 kg m-2 s-1) and heat flux (132 – 272 kW m-2) values. Results were comparatively presented via plain wall parallel microchannel heat sink (conventional heat sink, KIA). Inlet temperature of working fluid is kept constant at nearly 75 °C. Flow images were taken via high-speed camera (1000 fps), and the physical mechanism was scrutinized by supporting with the images. Compared to KIA, in the MIA, an improvement in two-phase heat transfer coefficient up to 827.2% is obtained, and flow boiling instabilities could be successfully suppressed. Contrary to enhancement in heat transfer, an increase up to 50.5% occurred for pressure drop. As general character, for both the heat sinks, effect of mass flux on pressure drop is relatively negligible, and heat transfer coefficients decrease with increasing mass flux. Compared to KIA, results of MIA are relatively more influenced from variation in mass flux.

Keywords

Artificial Nucleation Sites, Expansion of Cross Section, Flow Boiling, Microchannel

Project Number

219M142

References

• [1] T. G. Karayiannis and M. M. Mahmoud, “Flow boiling in microchannels: Fundamentals and applications,” Appl. Therm. Eng., vol. 115, pp. 1372–1397, 2017, doi: 10.1016/j.applthermaleng.2016.08.063.
• [2] D. Deng, L. Zeng, and W. Sun, “A review on flow boiling enhancement and fabrication of enhanced microchannels of microchannel heat sinks,” Int. J. Heat Mass Transf., vol. 175, p. 121332, 2021, doi: 10.1016/j.ijheatmasstransfer.2021.121332.
• [3] G. Liang and I. Mudawar, “Review of channel flow boiling enhancement by surface modification, and instability suppression schemes,” Int. J. Heat Mass Transf., vol. 146, p. 118864, 2020, doi: 10.1016/j.ijheatmasstransfer.2019.118864.
• [4] J. Tang, Y. Liu, B. Huang, and D. Xu, “Enhanced heat transfer coefficient of flow boiling in microchannels through expansion areas,” Int. J. Therm. Sci., vol. 177, no. February, p. 107573, 2022, doi: 10.1016/j.ijthermalsci.2022.107573.
• [5] A. Koşar and Y. Peles, “Boiling heat transfer in a hydrofoil-based micro pin fin heat sink,” Int. J. Heat Mass Transf., vol. 50, no. 5–6, pp. 1018–1034, 2007, doi: 10.1016/j.ijheatmasstransfer.2006.07.032.
• [6] A. Ma, J. Wei, M. Yuan, and J. Fang, “Enhanced flow boiling heat transfer of FC-72 on micro-pin-finned surfaces,” Int. J. Heat Mass Transf., vol. 52, no. 13–14, pp. 2925–2931, 2009, doi: 10.1016/j.ijheatmasstransfer.2009.02.031.
• [7] C. Woodcock, X. Yu, J. Plawsky, and Y. Peles, “Piranha Pin Fin (PPF) - Advanced flow boiling microstructures with low surface tension dielectric fluids,” Int. J. Heat Mass Transf., vol. 90, pp. 591–604, 2015, doi: 10.1016/j.ijheatmasstransfer.2015.06.072.
• [8] C. Falsetti, M. Magnini, and J. R. Thome, “A new flow pattern-based boiling heat transfer model for micro-pin fin evaporators,” Int. J. Heat Mass Transf., vol. 122, pp. 967–982, 2018, doi: 10.1016/j.ijheatmasstransfer.2018.02.050.
• [9] Y. Zhang, B. Liu, J. Zhao, Y. Deng, and J. Wei, “Experimental study of subcooled flow boiling heat transfer on micro-pin-finned surfaces in short-term microgravity,” Exp. Therm. Fluid Sci., vol. 97, no. February, pp. 417–430, 2018, doi: 10.1016/j.expthermflusci.2018.05.003.
• [10] Y. Wang, J. -heon Shin, C. Woodcock, X. Yu, and Y. Peles, “Local, transient heat transfer measurements for flow boiling in a microchannel with a pin fin,” Int. J. Heat Mass Transf., vol. 134, pp. 377–387, 2019, doi: 10.1016/j.ijheatmasstransfer.2019.01.048.
• [11] D. Deng, L. Chen, W. Wan, T. Fu, and X. Huang, “Flow boiling performance in pin fin- interconnected reentrant microchannels heat sink in different operational conditions,” Appl. Therm. Eng., vol. 150, no. August 2018, pp. 1260–1272, 2019, doi: 10.1016/j.applthermaleng.2019.01.092.
• [12] K. Lingjian, L. Zhigang, J. Lei, L. Mingming, L. Ying, “Experimental study on flow and heat transfer characteristics at onset of nucleate boiling in micro pin fin heat sinks,” Exp. Therm. Fluid Sci., vol. 115, no. April 2019, 2020, doi: 10.1016/j.expthermflusci.2019.109946.
• [13] D. Deng, L. Zeng, W. Sun, G. Pi, and Y. Yang, “Experimental study of flow boiling performance of open-ring pin fin microchannels,” Int. J. Heat Mass Transf., vol. 167, p. 120829, 2021, doi: 10.1016/j.ijheatmasstransfer.2020.120829.
• [14] L. Qin, S. Li, X. Zhao, and X. Zhang, “Experimental research on flow boiling characteristics of micro pin-fin arrays with different hydrophobic coatings,” Int. Commun. Heat Mass Transf., vol. 126, no. July, p. 105456, 2021, doi: 10.1016/j.icheatmasstransfer.2021.105456.
• [15] B. Markal and B. Kul, “Combined influence of artificial nucleation site and expanding cross section on flow boiling performance of micro pin fins,” Int. Commun. Heat Mass Transf., vol. 135, p. 106081, 2022, doi: 10.1016/j.icheatmasstransfer.2022.106081.
• [16] P. S. Lee and S. V. Garimella, “Saturated flow boiling heat transfer and pressure drop in silicon microchannel arrays,” Int. J. Heat Mass Transf., vol. 51, no. 3–4, pp. 789–806, 2008, doi: 10.1016/j.ijheatmasstransfer.2007.04.019.
• [17] T. Alam, P. S. Lee, C. R. Yap, and L. Jin, “Experimental investigation of local flow boiling heat transfer and pressure drop characteristics in microgap channel,” Int. J. Multiph. Flow, vol. 42, pp. 164–174, 2012, doi: 10.1016/j.ijmultiphaseflow.2012.02.007.
• [18] B. Markal, B. Kul, M. Avci, and R. Varol, “Effect of gradually expanding flow passages on flow boiling of micro pin fin heat sinks,” Int. J. Heat Mass Transf., vol. 197, p. 123355, 2022, doi: 10.1016/j.ijheatmasstransfer.2022.123355.
• [19] M. Law, P. S. Lee, and K. Balasubramanian, “Experimental investigation of flow boiling heat transfer in novel oblique-finned microchannels,” Int. J. Heat Mass Transf., vol. 76, pp. 419–431, 2014, doi: 10.1016/j.ijheatmasstransfer.2014.04.045.
• [20] M. Law and P. S. Lee, “Effects of varying secondary channel widths on flow boiling heat transfer and pressure characteristics in oblique-finned microchannels,” Int. J. Heat Mass Transf., vol. 101, pp. 313–326, 2016, doi: 10.1016/j.ijheatmasstransfer.2016.05.055.
• [21] W. Wan, D. Deng, Q. Huang, T. Zeng, and Y. Huang, “Experimental study and optimization of pin fin shapes in flow boiling of micro pin fin heat sinks,” Appl. Therm. Eng., vol. 114, pp. 436–449, 2017, doi: 10.1016/j.applthermaleng.2016.11.182.
• [22] S. J. Kline and F. A. McClintock, “Describing Uncertainties in Single-Sample Experiments,” Mechanical Engineering, vol. 75, no. 1, pp. 3-8, 1953.