本論文以實驗量測的方式，探討將水以及氧化鋁奈米流體與24烷奈米相變化乳液三者分別通入單層之微米流道熱沉，以及通入毫/微米流道疊置雙層熱沉所得之熱傳増益與壓降降幅。本實驗中之單層微米流道熱沉是單一微米流道所組成之實驗迴路，而毫/微米流道疊置雙層熱沉是以一微米流道熱沉上再疊置一層毫米流道熱沉所組成，毫米流道及微米流道皆以無氧銅進行線切割加工而成，其流道數量是以倍數製作，微米流道數量為毫米流道的兩倍，兩流道總寬度皆為14.6mm，流道總長度為50mm，其中毫米流道熱沉有13條長度50mm、寬度0.7mm、高度2.8mm的矩形流道，水力直徑為1.12mm，微米流道熱沉有26條長度50mm、寬度0.3mm、高度1.2mm的矩形流道，水力直徑為0.48mm，本實驗此次使用氧化鋁奈米流體搭配24烷相變化乳液通入雙層流道熱沉，期許能有更佳之熱傳效益與更低之平均壁溫。實驗在等熱通量條件下進行，固定電源供應器給定相等的電流與電壓，供給穩定的熱通量，並設定入口溫度為50度，後以不同流率進行實驗，最後將實驗數據進行處理與結果分析。
從實驗可發現相變化乳液在單層微米流道有最佳之效果，在雙層微米流道熱沉當中，使用(奈米流體/相變化乳液)可有效帶走相變化乳液來不及帶走之熱量，與純水組合相比擁有最佳之熱傳效果。

This paper explores the thermal performance and pressure drop reduction achieved by experimentally measuring the effects of introducing water, alumina nanoparticle fluid, and 24-alkane nanoparticle phase change emulsion into single-layer microchannel heat sinks. The single-layer microchannel heat sink consists of a single microchannel loop, while the dual-layer heat sink comprises a microchannel layer stacked on top of a macrochannel layer. Both mini and micro channels are fabricated using oxygen-free copper through wire-cutting processes. The number of channels is in multiples, with the microchannel count being double that of the minichannel count. The total width of both types of channels is 14.6mm, and the total length is 50mm. The macrochannel heat sink features 13 rectangular channels with dimensions of 0.7mm in width, and 2.8mm in height, having a hydraulic diameter of 1.12mm. The microchannel heat sink includes 26 rectangular channels measuring 0.3mm in width, and 1.2mm in height, with a hydraulic diameter of 0.48mm. In this experiment, an alumina nanoparticle fluid combined with 24-alkane phase change emulsion is introduced into the dual-layer heat sink configuration to enhance heat transfer efficiency and maintain lower average wall temperatures. The experiments are conducted under constant heat flux conditions, with a stable heat flux . The inlet temperature is set at 50 degrees Celsius, and experiments are carried out at various flow rates.
The mass fraction of the nano-PCM emulsion was 4.87% . The experimental operating condition such as the following the range of the Reynolds number of the single-layer microchannel heat sink from 455.73 to 1605.40. The ratio of flow rate is upper channel to lower channel =0.50、1.00、1.50、2.00、2.73 and 3.50 . And the total flow rate of the mini- and micro-channel stacked double-layer heat sink is the same as the single-layer microchannel heat sink.
From the experiments, it is observed that the phase change emulsion performs optimally in the single-layer microchannel heat sink. In the dual-layer microchannel heat sink configuration, using (nanoparticle fluid/phase change emulsion) effectively removes heat from the phase change emulsion before it can dissipate, resulting in superior heat transfer compared to the pure water configuration.

[1] D. B. Tuckerman and R. F. W. Pease, "High-performance heat sinking for VLSI," IEEE Electron Device Letters, vol. 2, no. 5, pp. 126-129, 1981
[2] W. Qu and I. Mudawar, "Experimental and numerical study of pressure drop and heat transfer in a single-phase micro-channel heat sink," International Journal of Heat and Mass Transfer, vol. 45, no. 12, pp. 2549-2565, 2002/06/01
[3]T.S,Ravigururajan , Cuta J , McDonald,C E , Drost,M K , "Single-phase flow thermal performance characteristic of a parallel microchannel heat exchanger," national heat transfer conference ,Volume 7. 1996/12/31
[4] P.-S. Lee, S. V. Garimella, and D. Liu, "Investigation of heat transfer in rectangular microchannels," International Journal of Heat and Mass Transfer, vol. 48, no.9,pp.1688-1704,2005/04/01
[5] Weilin Qu, Gh.Mohiuddin Mala, Dongqing Li, "heat transfer for water flow in trapezoidal silicon microchannels," International Communications in Heat and Mass Transfer, vol. 43, no. 21, pp. 3925-3936, 2000/11/01
[6] P. Gunnasegaran, H. A. Mohammed, N. H. Shuaib, and R. Saidur, "The effect of geometrical parameters on heat transfer characteristics of microchannels heat sink with different shapes," International Communications in Heat and Mass Transfer, vol. 37, no. 8, pp. 1078-1086, 2010/10/01
[7] H. Yun, B. Chen, and B. Chen, "Numerical Simulation of Geometrical Effects on the Liquid Flow and Heat Transfer in Smooth Rectangular Microchannels," International Conference on Micro/Nanoscale Heat Transfer, vol. 3, pp. 271-277, 2010, doi: 10.1115/MNHMT2009-18413.
[8] H. S. Kou , Ji-Jen Lee , and Chih-Wei Chen , "Optimum thermal performance of microchannel heat sink by adjusting channel width and height," International Communications in Heat and Mass Transfer, vol. 35, no. 5, pp. 577-582, 2008/05/01/ 2008
[9] R J Wang , Jia-wei Wang , Bei-qi Lijin , Ze-fei Zhu, "Parameterization investigation on the microchannel heat sink with slant rectangular ribs by numerical simulation," International Communications in Heat and Mass Transfer, vol. 133, no. 25, pp. 428-438, 2018/03/25
[10] H. A. Mohammed, P. Gunnasegaran, and N. H. Shuaib, "Influence of channel shape on the thermal and hydraulic performance of microchannel heat sink," International Communications in Heat and Mass Transfer, vol. 38, no. 4, pp. 474-480, 2011/04/01
[11] V. Leela Vinodhan and K. S. Rajan, "Fine-tuning width and aspect ratio of an improved microchannel heat sink for energy-efficient thermal management," Energy Conversion and Management, vol. 105, pp. 986-994, 2015/11/15
[12] S. U. S. Choi and J. A. Eastman, "Enhancing thermal conductivity of fluids with nanoparticles," United States, 1995-10-01 1995, Research Org.: Argonne National Lab. (ANL), Argonne, IL (United States), Sponsor Org.: USDOE, Washington, DC (United States), doi: Conference: 1995 International mechanical engineering congress and exhibition, San Francisco, CA (United States), 12-17 Nov 1995; Other Information: PBD: Oct 1995
[13] Fahad S. Alkasmoul, Mohammed Asaker, Ahmed Almogbel, Ahmed AlSuwailem, "Combined effect of thermal and hydraulic performance of different nanofluids on their cooling efficiency in microchannel heat sink," Case Studies in Thermal Engineering, vol. 30, 101766, 2022/02/01
[14] T.-C. Hung, W.-M. Yan, X.-D. Wang, and C.-Y. Chang, "Heat transfer enhancement in microchannel heat sinks using nanofluids," International Journal of Heat and Mass Transfer, vol. 55, no. 9, pp. 2559-2570, 2012/04/01
[15] Jaeseon Lee , Issam Mudawar , "Assessment of the effectiveness of nanofluids for single-phase and two-phase heat transfer in micro-channels," International Journal of Heat and Mass Transfer, vol. 50, no. 3-4, pp. 452-463, 2007/02
[16] C. J. Ho, L. C. Wei, and Z. W. Li, "An experimental investigation of forced convective cooling performance of a microchannel heat sink with Al2O3/water nanofluid," Applied Thermal Engineering, vol. 30, no. 2, pp. 96-103, 2010/02/01
[17] Rami Sabbah , Mohammad M. Farid , Said Al-Hallaj , "Micro-channel heat sink with slurry of water with micro-encapsulated phase change material: 3D-numerical study," Applied Thermal Engineering, vol. 29, no. 2-3, pp. 445-454, 2009/02
[18] S. Kuravi, K. M. Kota, J. Du, and L. C. Chow, "Numerical Investigation of Flow and Heat Transfer Performance of Nano-Encapsulated Phase Change Material Slurry in Microchannels," Journal of Heat Transfer, vol. 131, no. 6, 2009
[19] C. J. Ho, S.-T. Hsu, J.-H. Jang, S. F. Hosseini, and W.-M. Yan, "Experimental study on thermal performance of water-based nano-PCM emulsion flow in multichannel heat sinks with parallel and divergent rectangular mini-channels," International Journal of Heat and Mass Transfer, vol. 146, p. 118861, 2020/01/01
[20] K. Vafai and L. Zhu, "Analysis of two-layered micro-channel heat sink concept in electronic cooling," International Journal of Heat and Mass Transfer, vol. 42, no. 12, pp. 2287-2297, 1999/06/01
[21] T.-C. Hung, W.-M. Yan, and W.-P. Li, "Analysis of heat transfer characteristics of double-layered microchannel heat sink," International Journal of Heat and Mass Transfer, vol. 55, no. 11, pp. 3090-3099, 2012/05/01
[22] M.R. Hajmohammadi , I. Toghraei, " Optimal design and thermal performance improvement of a double-layered microchannel heat sink by introducing Al2O3 nano-particles into the water," Physica A: Statistical Mechanics and its Applications, vol. 505 , pp. 328-344, 2018/09/01
[23] 彭建凱, 毫/微米流道疊置雙層熱沉內分流水/氧化鋁奈米流體之強制對流熱散逸效能實驗研究 = Experimental study on forced convection heat dissipation efficacy of concurrent flow of water/Al2O3 nanofluid through a mini- and micro-channel stacked double-layer heat sink. 2020.
[24] 潘霽, 毫/微米流道疊置雙層熱沉內水/相變化奈米乳液之強制對流熱散逸效能實驗研究 = Experimental study on forced convection heat dissipation efficacy of water/Nano PCM emulsion through a mini- and micro-channel stacked double-layer heat sink. 2021.
[25] C. O. Popiel and J. Wojtkowiak, "Simple Formulas for Thermophysical Properties of Liquid Water for Heat Transfer Calculations (from 0°C to 150°C)," Heat Transfer Engineering, vol. 19, no. 3, pp. 87-101, 1998
[26] S. Shen, J. L. Xu, J. J. Zhou, and Y. Chen, "Flow and heat transfer in microchannels with rough wall surface," Energy Conversion and Management, vol. 47, no. 11-12, pp. 1311-1325, 2006, doi: 10.1016/j.enconman.2005.09.001.
[27] C.-J. Ho, W.-C. Chen, and W.-M. Yan, "Experimental study on cooling performance of minichannel heat sink using water-based MEPCM particles," International Communications in Heat and Mass Transfer, vol. 48, pp. 67-72, 2013, doi: 10.1016/j.icheatmasstransfer.2013.08.23.
[28] J. Lee and I. Mudawar, "Assessment of the effectiveness of nanofluids for single-phase and two-phase heat transfer in micro-channels," International Journal of Heat and Mass Transfer, vol. 50, no. 3-4, pp. 452-463, 2007, doi: 10.1016/j.ijheatmasstransfer.2006.08.001.
[29] M. E. Steinke and S. G. Kandlikar, "Single-phase liquid friction factors in microchannels," International Journal of Thermal Sciences, vol. 45, no. 11, pp. 1073-1083, 2006, doi: 10.1016/j.ijthermalsci.2006.01.016.
[30] B. Agostini, A. Bontemps, and B. Thonon, "Effects of Geometrical and Thermophysical Parameters on Heat Transfer Measurements in Small-Diameter Channels," Heat Transfer Engineering, vol. 27, no. 1, pp. 14-24, 2006, doi: 10.1080/01457630500341656.
[31] P.-S. Lee, S. V. Garimella, and D. Liu, "Investigation of heat transfer in rectangular microchannels," International Journal of Heat and Mass Transfer, vol. 48, no. 9, pp. 1688-1704, 2005, doi: 10.1016/j.ijheatmasstransfer.2004.11.019.
[32] Y. Rao, F. Dammel, and P. Stephan, "Experiments on the Cooling Performance of Microencapsulated Phase Change Material Suspension Flow in Rectangular," Heat Transfer Summer Conference pp. 923-929, 2009, doi: 10.1115/HT2007-32116.
[33] C. O. Popiel and J. Wojtkowiak, "Simple Formulas for Thermophysical Properties of Liquid Water for Heat Transfer Calculations (from 0°C to 150°C)," Heat Transfer Engineering, vol.19,no.3,pp.87-101, 1998, doi: 10.1080/01457639808939929.