Experimental And Numerical Analysis On The Cooling Performance Of Synthetic Jet At Low Reynolds Number

• Main Author: Ho, Roger Zhen Yu
• Format: Thesis
• Language: English
• Published: 2018
• Subjects: T Technology; TJ181-210 Mechanical movements
• Online Access: http://eprints.usm.my/44594/1/Experimental%20And%20Numerical%20Analysis%20On%20The%20Cooling%20Performance%20Of%20Synthetic%20Jet%20At%20Low%20Reynolds%20Number.pdf; http://eprints.usm.my/44594/

Jet sintetik adalah satu kaedah yang berpotensi dalam penyejukan mikroelektronik. Dengan ciri-ciri aliran bendalir aktif dan sifar aliran jisim bersih, jet sintetik merupakan satu peranti yang cekap dalam penyejukan mikroelektronik. Dalam kajian ini, prestasi penyejukan jet sintetik pneumatik disiasat dengan nombor Reynolds yang rendah. Kedua-dua eksperimen dan simulasi berangka dijalankan. Siasatan dijalankan dengan dua susunan yang berbeza. Udara yang dijana daripada rongga jet sintetik dihantar secara mendatar. Seterusnya, aliran udara dihantar secara menegak. Parameter-parameter kajian dilakukan berdasarkan lapan nombor Reynolds jet sintetik yang berbeza, kuasa dibekalkan kepada sink haba, dan jarak antara orifis dan sinki haba. Kajian ini menunjukkan bahawa peningkatan frekuensi jet sintetik meningkatkan halaju udara dan membawa kepada prestasi penyejukan yang lebih baik. Kajian ini juga menunjukkan bahawa pemalar pemindahan haba jet sintetik adalah dua kali lebih tinggi daripada perolakan semulajadi. Keputusan juga menunjukkan bahawa apabila kuasa yang dibekalkan meningkat, lebih tinggi nombor Nusselt dan secara tidak langsung membekalkan prestasi yang lebih baik dalam penyejukan jet sintetik. Walau bagaimanapun, sekiranya jarak antara orifis dan sinki haba ditingkatkan, prestasi penyejukan akan merosot. Jarak 0 cm menghasilkan 20% permindahan haba lebih baik daripada jarak 1 cm. Kajian ini juga menunjukkan susunan udara secara mendatar mempunyai prestasi penyejukan 8% lebih tinggi berbanding dengan susunan aliran udara menegak. _______________________________________________________________________________________________________ Synthetic jet is a potential alternative for microelectronic cooling. With the active fluid flow characteristic and zero net mass flow, the synthetic jet has been considered as the high-efficiency device in cooling microelectronic devices. In this study, a pneumatic synthetic jet with low Reynolds number is investigated for the cooling performance of an aluminium heat sink. Both experimental study and numerical simulations are conducted. The investigations are carried out with two different arrangements. The air is generated from the synthetic jet in the cavity and delivers horizontally to the heated heat sink through the orifices. Another arrangement is vertical air flow delivered upward from the synthetic jet to the heated heat sink through the orifices. The characteristics study is performed at eight different Reynolds number of the synthetic jet, power supplied to the heat sink, and the distance between the orifices and the heat sink. The study shows that as the driven frequency of the synthetic jet increases, the airflow velocity also increases, and it leads to an improved cooling performance. The findings show that the heat transfer coefficient of the synthetic jet is two times higher than that of the natural convection. The results also show that as the power supplied increases, Nusselt number increased which lead to the better cooling performance of the synthetic jet. However, as the distance of the orifices to the heated heat sink increases, the cooling performance is eventually decreased. The distance of 0 cm results in 20% higher heat transfer coefficient as compared to the distance of 1 cm. The study also reveals that the horizontal air flow arrangement provides 8% higher cooling performance as it is compared to the vertical air flow arrangement.