標題: Saturated flow boiling heat transfer of R-410A and associated bubble characteristics in a narrow annular duct
作者: Chen, C. A.
Li, K. W.
Lie, Y. M.
Lin, T. F.
機械工程學系
Department of Mechanical Engineering
關鍵字: Saturated flow boiling heat transfer;R-410A;Bubble characteristics;Mini-channel
公開日期: 1-十一月-2011
摘要: Experiments are conducted here to investigate how the channel size affects the R-410A saturated flow boiling heat transfer and associated bubble characteristics in a horizontal narrow annular duct. The gap of the duct is fixed at 1.0 and 2.0 mm in this study. The measured data indicate that the saturated flow boiling heat transfer coefficient increases with increasing refrigerant mass flux and saturated temperature and with a decrease in the gap size. Besides, raising the imposed heat flux can cause a significant increase in the boiling heat transfer coefficient. The results from the flow visualization show that the mean diameter of the bubbles departing from the heating surface decreases slightly with increasing refrigerant mass flux and saturated temperature. Moreover, the bubble departure frequency increases at reducing duct size and increasing mass flux. And at a high imposed heat flux many bubbles generated from the cavities in the heating surface tend to merge together to form big bubbles. Meanwhile, comparisons of the present heat transfer data for R-410A with R-407C and R-134a in the same duct and with some existing correlations are conducted. Furthermore, an empirical correlation for the present R-410A saturated flow boiling heat transfer data is proposed. (C) 2011 Elsevier Ltd. All rights reserved.
URI: http://dx.doi.org/10.1016/j.ijheatmasstransfer.2011.07.012
http://hdl.handle.net/11536/18452
ISSN: 0017-9310
DOI: 10.1016/j.ijheatmasstransfer.2011.07.012
期刊: INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
Volume: 54
Issue: 23-24
起始頁: 4988
結束頁: 5000
顯示於類別:期刊論文