會議名稱:

ISMNT-6 (The 6th International Symposium on Micro and Nano Technology)

Fig.1 ISMNT-6

會議重點:

International Symposium on Micro and Nano Technology (ISMNT) are a series of meetings sponsored by the Pacific Center of Thermal-Fluids Engineering (PCTFE) and started in 2004. The previous ISMNT meetings were held in: 2004 in Honolulu, 2006 in Hsinchu, 2009 in Seoul, 2013 in Shanghai and 2015 in Calgary. The 6th ISMNT will be held in Kyushu University, Fukuoka, Japan, in 19-22 March 2017. 
This symposium will bring together international researchers and engineers focusing on micro and nanoscale technology in energy conversion and transport in a variety of applications. It will provide a forum for the presentation of state-of-the-art researches and opportunities for technical interactions among participants. We look forward to fruitful discussion and intimate friendship in Fukuoka.

會議地點:

Held Centennial Hall Kyushu University

Fig.2 ISMNT-6 地點

我報告的內容:

題目: Flow Boiling Heat Transfer of Refrigerant HFO-1234yf in Micro-Channels

摘要:

Owing to the global warming effect consideration, the refrigerants with GWP value higher than 150 will be banned for applying in automotive air-condition systems from 2017 by the European Commission. The study on the replacement of high GWP refrigerant such as HFC-134a becomes an important and urgent issue in the coming years. Recently, a new refrigerant, HFO-1234yf has been developed with similar thermodynamic properties to HFC-134a but much lower GWP value (GWP = 4 in comparing to 1,430 of HFC-134a). It is expected as a good candidate of replacing the refrigerant HFC-134a. The automotive air-condition systems generally use brazed Aluminum flat tubes with parallel micro-channels as their evaporators. However, very few researches have been published regarding to the in tube two-phase heat transfer performance of HFO-1234yf especially in the micro-channels.

This study provides and experimental comparison of flow boiling heat transfer coefficient of HFO-1234yf and HFC-134a in micro-channels. The test results show that the single-phase liquid friction factors and heat transfer coefficients in micro-channels agree well with those predicted by the Blasius [1913] and Gnielinski [1976] correlations respectively. The flow boiling heat transfer coefficients and pressure drops of HFO-1234yf are slightly lower than HFC-134a due to properties differences. At the higher mass velocity and high vapor quality conditions, there is a sudden decrease of heat transfer coefficient and pressure drop owing to the partial dryout condition. Since the liquid density of the HFO-1234yf is lower than that of HFC-134a, dryout point of HFO-1234yf happened slightly earlier than HFC-134a. Based on the experimental results, HFO-1234yf has lower heat transfer but low pressure drops in comparing to HFC-134a. The overall heat transfer performance of these two refrigerants in evaporators depends on the appropriate number of flow pass and flow passages design.

會議照片:

Fig.1 ISMNT-6 Welcome reception

Fig.2 ISMNT-6 Plenary session location

Fig.3 ISMNT-6 David’s presentation

Fig.4 ISMNT-6 David’s presentation

Fig.5 ISMNT-6 Banquet

Fig.6 ISMNT-6 Banquet