[雙語翻譯]--外文翻譯--納米顆粒形狀對使用丙酮基al2o3 納米流體的平板熱管熱阻影響（原文）

1、The effect of nanoparticle shape on the thermal resistance of a flat-plate heat pipe using acetone-based Al2O3 nanofluidsHyun Jin Kim, Seung-Hyun Lee, Soo Bin Kim, Seok Pil Jang ?School of Aerospace and Mechanical Engine

2、ering, Korea Aerospace University, Goyang, Gyeonggi-do 412-791, Republic of Koreaa r t i c l e i n f oArticle history:Received 1 May 2015Received in revised form 4 September 2015Accepted 5 September 2015Keywords:Flat-pla

3、te heat pipeAl2O3 nanofluidsThinPorous layerNanoparticle shapea b s t r a c tIn this paper, we experimentally investigate the effect of the shape of nanoparticles in acetone-basedAl2O3 nanofluids on the thermal resistanc

4、e of a flat-plate heat pipe. Acetone-based Al2O3 nanofluidscontaining sphere-, brick- and cylinder-shaped nanoparticles were prepared, using the two-step methodwithout any surfactants or additives. The flat-plate heat pi

5、pes are manufactured with the prepared threenanofluids. The thermal resistances of the flat-plate heat pipes are experimentally obtained. The resultsshow that the thermal resistances of the flat-plate heat pipes with nan

6、ofluids containing sphere-, brick-and cylinder-shaped nanoparticles are reduced to 33%, 29%, and 16%, respectively, compared with thethermal resistance of the flat-plate heat pipe with pure acetone. Based on the results,

7、 we demonstratethat the shape of nanoparticles in working nanofluids significantly affects the thermal resistance of theheat pipes. Finally, we discuss why nanoparticle shape in nanofluids reduces the thermal resistance

8、ofthe flat-plate heat pipe using a theoretical approach presented in literature.? 2015 Elsevier Ltd. All rights reserved.1. IntroductionBecause the thermal resistance of heat pipes critically depends on the thermal chara

9、cteristics of working fluids, the superior ther- mal characteristics of working fluids are essential to improving the thermal performance of heat pipes. Therefore, many research groups have applied nanofluids to heat pip

10、es as the next genera- tion of working fluids [1–22] due to the outstanding thermophys- ical properties of nanofluids. Their research experimentally and theoretically showed a remarkable reduction in the thermal resis- t

11、ance of the heat pipes with nanofluids and also explained the rea- son for this reduction with the enhancement of nanofluids’ thermophysical properties and the modification of the surface characteristics at the evaporati

12、on section. Especially, several researchers [9–22] hypothesized that the thin porous layer formed by nanoparticles on the wick plays a significant role in reducing the thermal resistance of the heat pipes with nanofluids

13、. They pre- sented the thin porous layer at evaporation section changes the surface characteristics such as the reduction of contact angle, and the increase of wettability, capillary force and thin film. In addi- tion, t

14、hey reported that the enhanced thermophysical properties of nanofluids cannot be a key factor for the reduced thermal resis- tance. Moreover, Do and Jang [15] mathematically presented thatthis layer of nanoparticles on t

15、he wick is in fact the primary factor in the reduced thermal resistance. Recently Solomon et al. [18] deposited nanoparticles on the wick’s surface to identify their effect on the thermal performance of heat pipes. They

16、suggested the coated wick reduced the wall temperature at the evaporator and condenser. Also, Kole and Dey [21] experimentally showed that a thin porous layer of Cu nanoparticles suspended in water- based Cu nanofluids m

17、ay enhance the thermal performance of nanofluid heat pipes. In this study, we experimentally measure the thermal resis- tances of flat-plate heat pipes with acetone-based Al2O3 nanofluids containing nanoparticles of diff

18、erent shapes. Our goal is to under- stand how nanofluids affect the thermal resistance of the heat pipe: (1) their role in thermal conductivity, (2) the effects of the nanofluid layer on the evaporator wick, and (3) the

19、effect of nanoparticle shape on thermal resistance. Acetone-based Al2O3 nanofluids containing sphere-, brick-, and cylinder-shaped nanoparticles are prepared, using the two-step method without any surfactants or additive

20、s. The flat-plate heat pipes are manufac- tured using three prepared nanofluids (one per shape of nanopar- ticle), and the thermal resistances of the flat-plate heat pipes are experimentally obtained. Based on the result

21、s, we clearly show that the key factor in the reduction in thermal-resistance is not the thermal conductivity of nanofluids but rather the coating of nanoparticles on the evaporator wick. We also discuss the effect of na

22、noparticle shape on both the nanoparticle layer and the thermal-resistance reduction of the heat pipes.http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.09.0130017-9310/? 2015 Elsevier Ltd. All rights reserved.? Corres

23、ponding author. Tel.: +82 2 300 0179; fax: +82 2 1 3158 4429.E-mail address: spjang@kau.ac.kr (S.P. Jang).International Journal of Heat and Mass Transfer 92 (2016) 572–577Contents lists available at ScienceDirectInternat

24、ional Journal of Heat and Mass Transferjournal homepage: www.elsevier.com/locate/ijhmtTo obtain the thermal resistance of the flat-plate heat pipe with the nanofluids, we set up an experimental system consisting of a hea

25、ting system, a circulation chiller, an insulation container (Cera- mic Fiber, k = 0.075 W/m K) and data acquisition (Agilent, 34970A) as shown in Fig. 2. The heating system at the evaporation region, which consists of a

26、copper block and a film heater supported by a power supply (Agilent 6030A), was used to perform the experi- ment under constant heat-flux condition. A circulation chiller (JEIOTECH, RW-1025G) was also used to maintain th

27、e temperature at the condenser region. In order to minimize contact resistance, a thermal pad (k = 1.55 W/m K, NANOTIM SPS) with 1-mm thickness was used between the heat pipe and copper block. J-type thermo- couples were

28、 used to measure the surface temperatures of the heat pipes. The geometry of the flat-plate heat pipe and positions of thermocouple soldering are depicted in Fig. 3. The thermal resistance of the flat-plate heat pipe bet

29、ween the evaporator and the condenser can be calculated as followsR ¼ Te ? Tc Qin ð1Þwhere Qin, Tc, and Te, input heat, average temperature at the con- densation region, and average temperature at the evap

30、orationregion, respectively. Using Eq. (1), the thermal resistance of the flat-plate heat pipe with the nanofluids can be obtained experimen-tally. The uncertainty analysis on the thermal resistance, Eq. (1) was performe

31、d as given byFig. 2. Schematic of experimental apparatus.170mm 120mm 10mm 40mm 70mmThermocouplesQout Qin30mm15mm50mm (Evaporation) 60mm (Adiabatic Section) 70mm (Condensation)180mmFig. 3. Flat-plate heat pipe used in pre