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研究生： 田政蔚
Cheng-Wei Tien
論文名稱： 加熱瓦數對R134a冷凍系統流量分佈之影響
Effect of Heat Load on the Flow Distribution of R134a Refrigeration System applicable to Electronic Cooling
指導教授： 許文震
Wen-Jenn Sheu
口試委員:
學位類別： 碩士
Master
系所名稱： 工學院 - 動力機械工程學系
Department of Power Mechanical Engineering
論文出版年： 2007
畢業學年度： 95
語文別： 英文
論文頁數： 71
中文關鍵詞： 流量分佈 、加熱瓦數 、R134a 、電子冷卻
外文關鍵詞： flow distribution, heat load, R134a, electronic cooling
相關次數： 點閱：53  下載：0 
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    • 本文中以實驗之方式研究加熱瓦數與冷凍系統應用在電子冷卻中流量分佈之影響。在一般情況下，實驗結果顯示加熱瓦數對於流量分佈有顯著而重要的影響。當瓦數增加時，其總流量將會隨之線性增加;而當瓦數遞減時，其總流量也會隨之減少。在此實驗尚做了在不同流道型式及不同入口乾度對於整體流量分佈的影響。在Diverge流道中，對於加熱瓦數相同之情形下，其流量分佈處為平均分配至兩平行且相同之蒸發器中，而當其一瓦數開始變化，即可從實驗結果中發現，流量對於有瓦數變化蒸發器之影響較另一蒸發器為大;對於其他兩種reverse及parallel型流動方向，其流量趨勢為相反且皆與diverge有相同之流量變化。
    在乾度的影響下，其流量分佈在從高降至低瓦數時較無明顯的趨勢走向，然而對於由低瓦數往上加之實驗中，可發現其流量分佈極為類似，此現象可能是因為其經過歧管流入蒸發器之壓升不足以使流量產生明顯的變化所致。

    The present study experimentally investigates mass flow rate distribution among symmetric heat sinks in conventional channel under a variety of test conditions. The test section consists of adjustable inlet and outlet headers with an inner diameter 4.35 mm which own three fundamental flow directions. The key experimental parameters are flow direction of refrigerant passing through the test section (diverge, reverse and parallel), inlet quality (0.1 and 0.01) and heat load. Different flow direction results in apparent contrast of mass flow rate in reverse and parallel flow schemes. The effect of inlet quality plays an important role in flow distribution and total mass flow rate. The effect of heat load on mass flow rate distribution results in apparent influence on flow distribution. Diverge flow direction initially shows good symmetry in flow distribution due to its arrangement of piping. Both reverse and parallel flow conditions show contrary flow distributions of heat sinks.

    Content 中文摘要……………………………………………………………I Abstract……………………………………………………………II 誌謝…………………………………………………………………III Content…………………………………………………………… IV Nomenclature………………………………………………………IX Chapter I Introduction…………………………………………1 1.1 Overview………………………………………………………1 1.2 Motivation……………………………………………………3 1.3 Destination……………………………………………… …5 Chapter II Literature Review…………………………………6 Chapter III Analysis and System Set Up……………………12 3.1 Overview………………………………………………………12 3.2 Equipments of the system…………………………………13 3.3 Experiment scheme………………………………… ………18 3.4 Measuring equipment…………………………… …………23 3.5 Experimental Apparatus……………………………………24 3.6 Test parameters…………………………………… ………25 3.7 Experiment Procedures…………………………… ………28 Chapter IV Results and Discussion……………………… …30 4.1 Analysis procedure…………………………………………30 4.2 50W&50W………………………………………………… ……31 4.2.1 Effect on flow distribution………………… ………31 4.2.2 Variation of mass flow ratio per watt…… ………33 4. 3 50W&50W at low quality……………………… …………34 4.3.1 Effect on flow distribution…………………… ……34 4.3.2 Variation of mass flow ratio per watt… …………34 4.4 Comparison of total mass flow rate……………………35 4.5 20W&20W…………………………………………… …………35 4.5.1 Effect on flow distribution……………… …………35 4.5.2 Variation of mass flow ratio per watt……… ……36 4.6 20W&20W at low quality……………………………………37 4.6.1 Effect on flow distribution………………… ………37 4.6.2 Variation of mass flow ratio…………………………37 4.7 Comparison of total mass flow rate……………………37 4.8 Examination of different starting heating power …38 4.9 Pressure Drop………………………………… …………38 4.9.1 Flow distribution due to pressure drop……………38 4.10 Superheated temperature…………………… …………40 4.10.1 50W&50W……………………………………………………40 4.10.2 50W&50W at low quality……………………… ………41 4.10.3 20W&20W …………………………… ……………………42 4.10.4 20W&20W at low quality………… ……………………42 4.11 Error Analysis……………… ……………………………43 Chapter V Conclusion and Future Work………………………44 5.1 Conclusion……………………………………………………44 5.2 Future Work…………………………………… ……………44 Chapter VI Literature Cited………………………… ………46 Chapter VII Photographs…………………… …………………49 Fig.2.1 Vapor-compression refrigeration system…………49 Fig.2.2 Schematic layout of the experiment system… …49 Fig. 2.3 Test Section………………………………… ………50 Fig. 2.4 Heat sink lay out……………………………………50 Fig. 2.5 Mini-Compressor………………………………………51 Fig. 2.6 Controller………………………………… …………51 Fig. 2.7 Cooling capacity and work input…………………51 Fig. 2.8 Condenser………………………………………………52 Fig. 2.9 Meter Valve……………………………………………52 Fig. 2.10 Evaporator……………………………………………52 Fig. 2.11 R-134a P-h chart……………………………………52 Fig. 2.12 Accumulator……………………………… …………53 Fig. 2.13 Manifold header…………………………… ………53 Fig. 2.14 The detailed size of evaporator…………… …53 Fig. 2.15 Standard temperature meter………………………54 Fig. 2.16 Pressure difference transmitter and correlation verification………………………………………………………54 Fig. 2.17 Cold-expanded tool…………………………………55 Fig. 2.18 PFA connection………………………………………55 Fig. 2.19 MX100 Recorder………………………………………55 Fig. 2.20 Qmax UM2202 Oscilloscope…………………………56 Fig. 2.21 Thermostat……………………………………………56 Fig. 2.22 SAGLnoMIYA DNS Pressure Controller……………56 Fig. 4.1 Mass flow distribution among symmetric evaporators in three flow directions starting from 50W heat load…57 Fig. 4.2 Variation of mass flow ratio in percentage of ratio among symmetric evaporators in three flow directions starting from 50W heat loads…………………………………58 Fig. 4.3 Mass flow ratio extended to the heat load of 80W of heat sink 1……………………………………………………59 Fig. 4.4 Mass flow distribution among symmetric evaporators in three flow directions starting from 50W heat loads at low quality……………………………………………… ………60 Fig. 4.5 Variation of mass flow ratio in percentage of ratio among symmetric evaporators in three flow directions starting from 50W heat loads at low quality…………… 61 Fig. 4.6 Comparison of total mss flow rate of different qualities…………………………………………………… ……61 Fig. 4.7 Mass flow distribution among symmetric evaporators in three flow directions starting from 20W heat loads……………………………………………………… ………62 Fig. 4.8 Variation of mass flow ratio in percentage of ratio among symmetric evaporators in three flow directions starting from 20W heat loads…………………………………63 Fig. 4.9 Mass flow distribution among symmetric evaporators in three flow directions starting from 20W heat load at low quality ……………………………………………………………64 Fig. 4.10 Variation of mass flow ratio in percentage of ratio among symmetric evaporators in three flow directions starting from 20W heat load……………………………… …65 Fig. 4.11 Comparison of total mass flow rate of different qualities……………………………………………………… …65 Fig. 4.12 Comparison of different starting heat loads in diverge flow type…………………………………………… …66 Fig. 4.13 Pressure drop in three flow types starting from 50W & 50W……………………………………………………… …67 Fig. 4.14 Pressure drop in three flow types starting from 50W & 50W at low quality………………………………………67 Fig. 4.15 Pressure drop in three flow types starting from 20W & 20W……………………………………………………… …68 Fig. 4.16 Pressure drop in three flow types starting from 20W & 20W at low quality………………………………………68 Fig. 4.17 Repeatability of pressure drop in diverge flow type starting from 50W & 50W…………………………………69 Fig. 4.18 Repeatability of pressure drop in diverge flow type starting from 20W & 20W…………………………………69 Fig. 4.19 Superheated temperature in three flow types starting from 50W heat load………………………… ………70 Fig. 4.20 Superheated temperature in three flow types starting from 50W & 50W at low quality……………………70 Fig. 4.21 Superheated temperature in three flow types starting from 20W & 20W…………………………………… …71 Fig. 4.22 Superheated temperature in three flow types starting from 20W & 20W at low quality……………………71

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