PDF Publication Title:
Text from PDF Page: 002
reported by Kathiravan et al. [17] showed that the presence of sur- factant enhances the nucleate pool boiling heat transfer. The exist- ing researches on the nucleate pool boiling heat transfer characteristics of refrigerant-based nanofluid without surfactant showed that the presence of nanoparticles has effect on the nucle- ate pool boiling heat transfer and the effect is related to the nano- particle concentration [18], resulting in the difference between the effect of surfactant on the nucleate pool boiling heat transfer of refrigerant-based nanofluid and those on pure water, organic fluids or water-organic fluid mixtures. The thermophysical properties of refrigerant are different from those of water, causing that the re- search related to the effect of surfactant on the nucleate pool boil- ing heat transfer of water-based nanofluid may not be extended to refrigerant-based nanofluid. Therefore, it is necessary to investi- gate the effect of surfactant on the nucleate pool boiling heat trans- fer characteristics of refrigerant-based nanofluid. The purpose of this paper is to experimentally investigate the effect of surfactant on the nucleate pool boiling heat transfer char- acteristics of refrigerant-based nanofluid, and to propose a correla- tion for predicting the nucleate pool boiling heat transfer coefficient of refrigerant-based nanofluid with surfactant. 2. Preparation and characterization of refrigerant-based nanofluid with surfactant The refrigerant-based nanofluid used in the present study is Cu-R113 nanofluid. Cu nanoparticle is one kind of the commonly used metal nanoparticles in nanofluid [19–23]. R113 is chosen as the host refrigerant, just as Peng et al. [24] did. R113 is in liquid state at atmospheric pressure and room temperature while the widely used refrigerants (e.g. R410A) are in vapor state, so it is much easier to prepare nanofluids based on R113 than those based on the widely used refrigerants. Cu nanoparticles with average diameter of 20 nm are produced by hydrogen direct current arc plasma evaporation method, and the TEM (transmission electron microscope) photograph of Cu nanoparticles is shown in Fig. 1. The properties of nanoparticle and liquid-phase refrigerant are listed in Table 1. Three types of surfactants including Sodium Dodecyl Sulfate (SDS), Cetyltrimethyl Ammonium Bromide (CTAB) and Sorbitan Monooleate (Span-80) are used in the experiments, and they are anionic, cationic and nonionic surfactants, respectively. The surfac- tants used in the experiments are miscible with R113. The physical and chemical properties of these three surfactants are listed in Table 2. In order to investigate the effects of surfactant concentra- tion and nanoparticle concentration on the nucleate pool boiling heat transfer, for Cu-R113 nanofluid with each type of surfactant, the surfactant concentrations (C) cover 200, 500, 1000, 2000 and 5000 ppm (parts per million by weight), and the nanoparticle con- centrations (x) cover 0.1, 0.5 and 1.0 wt.%. Cu-R113 nanofluids with surfactants are prepared by the fol- lowing steps: (1) weighing the required mass of Cu nanoparticles and surfactants by a digital electronic balance with a measurement range of 10 mg to 210 g and a maximum error of 0.1 mg; (2) putt- ing the Cu nanoparticles and surfactants into the weighed R113 to form the Cu-R113 nanofluids with surfactants; (3) vibrating the Cu-R113 nanofluids with surfactants by an ultrasonic processor for 1 h to disperse the nanoparticles evenly. Experimental observa- tion shows that the even dispersion of Cu nanoparticles in the Cu-R113 nanofluids with surfactants can be kept for more than 24 h. The duration of the experiment for each sample of Cu-R113 nanofluid with surfactant is less than 4 h which is shorter than 24 h. For the time duration same to the nucleate boiling experi- ment for each sample, the stability tests using the spectrophotom- H. Peng et al. / Experimental Thermal and Fluid Science 35 (2011) 960–970 961 Nomenclature a1, a2 C Cp dp Db h coefficients in Eq. (3) surfactant concentration isobaric specific heat (J kg1 K1) nanoparticle diameter (m) bubble departure diameter (m) nucleate pool boiling heat transfer coefficient (W m2 K1) molecular weight Greek symbols a thermal diffusivity (m2 s1) b contact angle (°) k thermal conductivity (W m1 K1) m kinematic viscosity (m2 s1) q density (kg m3) r surface tension (N m1) x nanoparticle concentration Subscripts c copper f saturated liquid, fluid g saturated vapor n nanoparticle s surfactant sat saturation w test surface M m1, m2, m3, m4, m5 coefficients in Eqs. (8) and (9) NER n1, n2 q Ra SER T nanoparticle enhancement ratio coefficients in Eqs. (8) and (9) heat flux (W m2) heating surface roughness (m) surfactant enhancement ratio temperature (°C) Fig. 1. TEM photographs of Cu nanoparticles.PDF Image | Experimental Thermal and Fluid Science 35
PDF Search Title:
Experimental Thermal and Fluid Science 35Original File Name Searched:
SCI_J2011145.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |