| 研究生: |
許庭瑋 Ting-wei Hsu |
|---|---|
| 論文名稱: |
以紅外線熱像分析冷媒R410A在板式熱交換器內之蒸發熱傳性能 |
| 指導教授: | 楊建裕 |
| 口試委員: | |
| 學位類別: |
碩士 Master |
| 系所名稱: |
工學院 - 能源工程研究所 Graduate Institute of Energy Engineering |
| 論文出版年: | 2012 |
| 畢業學年度: | 101 |
| 語文別: | 中文 |
| 論文頁數: | 84 |
| 中文關鍵詞: | 板式熱交換器 、分佈不不均 、入口分佈器 、紅外線熱像 |
| 外文關鍵詞: | Plate heat exchanger, mal-distribution, inlet port distributor, Infrared photograph |
| 相關次數: | 點閱:12 下載:0 |
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板式熱交換器作為蒸發器時,入口處的兩兩相冷冷媒因慣性力力與重力力 的作用,造成流流道入口的冷冷媒分佈不不均,為了了降降低此現象,目前多於 入口處裝置入口分佈器。但產生單一流流道內分佈不不均勻的問題,而入 可分佈器可藉由改變不不同的開孔方向改善單一流流道中兩兩相冷冷媒流流動 分佈不不均勻的問題。本研究利利用紅外線熱像儀觀察板片之溫度度場,並 且進一步分析在板式熱交換器內設置分佈器之後對於冷冷媒蒸發溫度度 場的影響。從板片表面溫度度場觀察結果可知,接近冷冷媒側流流道入出口 處之過熱面積會小於遠離離冷冷媒側入出口處之過熱面積,而此種現象在 設置入口分佈器以後則不不明顯。
若若固定過熱段與飽和段的熱傳量量比例例,冷冷媒雷雷諾諾數數越高則過熱面 積越小,原因是冷冷媒飽和段的熱傳機制主要被核沸騰主導。在相同的 熱傳量量下,同向流流動的過熱段面積較逆向流流大,原因是過熱段的兩兩側 流流體溫差較小。從局部熱傳係數數分析結果得知,設置分佈器以後熱傳 係數數較低(約減少 14%),此實驗結果歸因於冷冷媒流流經分佈器的時候所 造成的壓降降以及乾度度上升。在冷冷媒飽和段熱傳量量減少的情況下,其熱 傳係數數也相對減少。
Because the inertia force and gravity is different among liquid and vapor, there is flow mal-distribution in a header of plate heat exchanger when the refrigerant is two phase fluid. In order to reduce this phenomenon, some people install distributor in the header of exchanger, but the opening direction of distributor will affect refrigerant flow distribution in a channel. In this research an experimental study to visualize temperature distribution in the plate heat exchanger that in order to observe the effect of installing the optimum distributor in the plate evaporator. From temperature visualization results, the area of superheat near the side of refrigerant port is larger than that of near the side of water. This phenomenon is not obvious in the case of installed distributor.
If fix the ratio of heat among the single phase region and the two phase region, area of superheat become smaller when refrigerant rate become larger. The reason is that the main heat transfer mechanism in two phase region is nucleate boiling heat transfer. The area of superheat in counter flow case is smaller than parallel flow case. The reason is that the logarithmic mean temperature of single phase in the counter flow case is larger than the parallel case. Heat transfer coefficient in the case of installed distributor is smaller than the case of uninstalled distributor (about 14% reduced). This phenomenon is attributed to the pressure dropping and vapor quality rising when refrigerant flow through the distributor.
Ahmad, M., Berthoud, G. and Mercier, P, 2009, “General characteristics of two- phase flow distribution in a compact heat exchanger,” International Journal of Heat and Mass Transfer, Vol. 52, pp. 442- 450.
Asano, H. Takenaka, N. and Fujii, T., 2004, “Flow characteristics of gas- liquid two- phase flow in plate heat exchanger (Visualization and void fraction measurement by neutron radiography),” Experimental Thermal and Fluid Science, Vol. 28, pp. 223- 230.
Asano, H. Takenaka, N., Wakabayashi, T. and Fujii, T., 2005, “Visualization and void fraction distribution of downward Gas- liquid two- phase flow in a plate heat exchanger by neutron radiography,” Nuclear Instruments and Methods in Physics Research A, Vol. 542, pp. 154- 160.
Freund, S., Kabelac, S., 2010, “Investigation of local heat transfer coefficients in plate heat exchangers with temperature oscillation IR thermograghy and CFD,” International Journal of Heat and Mass Transfer, Vol. 53, pp. 3764- 3781.
Focke, W. W. and Knibbe P. G., 1984, “Flow visualization in parallel plate ducts with corrugated walls,” CSIR Report CENG M-519.
Focke, W. W. and Knibbe P. G., 1986, “Flow visualization in parallel- plate ducts with corrugated walls,” Journal of Fluid Mechanics, Vol. 165, pp. 73- 77.
61
Gherasim, I., Galanis, N., Nguyen, C. T., 2011, “Effects of smooth longitudinal passages and port configuration on the flow and thermal fields in a plate heat exchanger,” Applied Thermal Engineering, Vol. 31, pp.4113- 4124.
Giovanni, A. Longo, Andrea Gasparella, 2007, “HFC-410A vaporization inside a commercial brazed plate heat exchanger,” Experimental Thermal and Fluid Science, Vol. 32, pp. 107- 116.
Gradeck, M. and Lebouche, M, 2000, “Two-phase gas-liquid flow in horizontal corrugated channels,” International Journal of Multiphase Flow, Vol. 26, pp. 435- 443.
Gschwind, P., Gaiser, G., Zimmerer, C. and Kottke, V., 2001, “Transport phenomena in micro heat exchangers with corrugated walls,” Microscale Thermophysical Engineering, Vol. 5, pp. 285- 292.
Holman, J. P, 2001, “Experimental Methods For Engineers” , McGraw-Hill, Singapore, pp. 51- 60.
Jain, S., Joshi, A. and Bansal, P. K., 2007, “A new approach to numerical simulation of small sized plate heat exchangers with chevron plates,” Journal of Heat Transfer, Vol. 129, pp. 291- 297.
Kanaris, A. G., Mouza, A. A., Paras S. V., 2006, “Flow and Heat Transfer Prediction in a Corrugated Plate Heat Exchanger using a CFD Code,” Chemical Engineering and Technology, Vol. 29, No. 8, pp. 923- 930.
Kedzierski, M. A., 1997, “Effect of inclination on the performance of a
compact brazed plate condenser and evaporator,” Heat Transfer
Engineering, Vol. 18, No. 3, pp. 25- 38. 62

Lozano, A., Barreras, F., Fueyo, N., and Santodomingo, S., 2008, “The flow in an oil/water plate heat exchanger for the automotive industry,” Applied Thermal Engineering, Vol. 28, pp. 1109- 1117.
Marchitto, A., Devia, F., Fossa, M. and Guglielmini, G., 2008, “Experiments on two-phase flow distribution inside parallel channels of compact heat exchangers,” International Journal of Multiphase Flow, Vol. 34, pp. 128- 114.
Shah, R. K., 1990, “Assessment of Modified Plot Techniques for Obtaining Heat Exchanger Design Data,” Heat Transfer, Vol. 5, pp. 51- 56.
Shiomi, Y., Nakanishi, S. and Uehara, T., 2004, “Characteristics of two-phase flow in a channel formed by chevron type plates,” Experimental Thermal and Fluid Science, Vol. 28, pp. 231- 235.
Thonon, B., Vidil, R. and Marvillet, C., 1995, “Recent research and developments and plate heat exchangers,” Enhanced Heat Transfer, Vol. 2, pp. 149- 155.
Tribbe, C., and Muller- Steinhagen, H. M., 2001, “Gas/liquid flow in plate-and-frame heat exchangers-Part II: two phase multiplier and flow pattern analysis,” Heat Transfer Engineering, Vol. 22, pp. 12- 21.
Tsai, Y. C., Liu, F. B. and Shen, P. T., 2009, “Investigations of the pressure drop and flow distribution in a chevron-type plate heat exchanger,” International Communications in Heat and Mass Transfer, Vol. 36, pp. 574- 578.
63
Vist, S. and Pettersen, J., 2004, “Two-phase flow distribution in compact heat exchanger manifolds,” Experimental Thermal and Fluid Science, Vol. 28, pp. 209- 215.
Vlasogiannis, P., Karagiannis, G. Argyropoulos, P., and Bontozoglou, V., 2002, “Air- water two-phase flow and heat transfer in a plate heat exchanger,” International Journal of Multiphase Flow, Vol. 28, pp. 757- 772.
王啟川,2007,熱交換器設計,五南圖書出版有限公司,臺北北市。 朱彥丞,2012,板式熱交換器內部之兩兩相分佈模擬與流流動分佈不不均勻
性分析,國立立中央大學機械工程研究所碩士論論文,中壢。 林林立立偉,2004,水對冷冷媒 R22 在板式熱交換器內之性能測試分析,
國立立中央大學機械工程研究所碩士論論文,中壢。 孟繁宇,2011,水-空氣在板式熱交換器內的流流動觀察,國立立中央大
學機械工程研究所碩士論論文,中壢。
翁嘉鴻,2002,水對水板式熱交換器性能測試分析,國立立中央大學機 械工程研究所碩士論論文,中壢。
曾廣彬,2010,板式熱交換器支流流場模擬與流流動分佈佈均勻態分析, 國立立中央大學機械工程研究所碩士論論文,中壢。