Experimental investigation of flow boiling heat transfer enhancement under ultrasound fields in a minichannel heat sink
| Autor: | Bolin He, Xiao Jian, Fan Yu, Luo Xiaoping, Wen Wang, Zhang Jinxin |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Flow visualization
Low ultrasound power Materials science Acoustics and Ultrasonics Bubble Heat transfer enhancement lcsh:QC221-246 02 engineering and technology Heat sink 010402 general chemistry 01 natural sciences Inorganic Chemistry lcsh:Chemistry Heat exchanger Chemical Engineering (miscellaneous) Environmental Chemistry Radiology Nuclear Medicine and imaging Original Research Article Flow boiling business.industry Organic Chemistry Ultrasound Ultrasound radiation angle Mechanics 021001 nanoscience & nanotechnology Minichannel 0104 chemical sciences Heat flux lcsh:QD1-999 lcsh:Acoustics. Sound Ultrasonic sensor 0210 nano-technology business Low ultrasound frequency |
| Zdroj: | Ultrasonics Sonochemistry, Vol 70, Iss, Pp 105342-(2021) Ultrasonics Sonochemistry |
| ISSN: | 1350-4177 |
| Popis: | Highlights • Studying flow boiling heat transfer enhancement under ultrasound in minichannels. • Understanding effects of ultrasonic excitations and ultrasonic parameters. • Exploring mechanism of heat transfer enhancement under ultrasound by visualization. • Maximum enhancement ratios of have (1.62 for IU, 1.84 for IOU) are obtained. Ultrasound is considered to be an effective active heat transfer enhancement method, which is widely used in various fields. But there is no clear understanding of flow boiling heat transfer characteristics in micro/mini-channels under ultrasonic field since the studies related are limited up to now. In this paper, a novel minichannel heat exchanger with two ultrasonic transducers inside the inlet and outlet plenum respectively is designed to experimentally investigate the impacts of ultrasound on flow boiling heat transfer enhancement in a minichannel heat sink. Flow visualization analyses reveal that ultrasound can promote rapid bubble motion, bubble detachment from heating wall surface and thereby new bubble generation, and decrease the length of confined bubble. Furthermore, the flow boiling experiments are initiated employing working fluid R141b at different ultrasonic parameters (e.g., frequency, power, angle of radiation) and heat flux under three types of ultrasound excitations: no ultrasound (NU), single inlet ultrasound (IU), inlet and outlet ultrasound (IOU). The results indicate that ultrasound has obvious augmentation effects on flow boiling heat transfer even though the intensification effects will be limited with the heat flux increases. The higher ultrasonic power, the lower ultrasonic frequency and the higher ultrasonic radiation angle, the better intensification efficiency. The maximum enhancement ratio of have in the saturated boiling section reaches 1.88 at 50 W, 23 kHz and 45° under the experimental conditions. This study will be beneficial for future applications of ultrasound on flow boiling heat transfer in micro/mini-channels. |
| Databáze: | OpenAIRE |
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