Filtry
wszystkich: 64
wybranych: 60
Wyniki wyszukiwania dla: nanofluids
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Pool boiling of water-Al2O3 and water-Cu nanofluids on horizontal smooth tubes
PublikacjaPrzedstawiono wyniki pomiarów współczynnika przejmowania ciepła podczas wrzenia dwóch nanocieczy, tj. woda-Al2O3 i woda-Cu o trzech koncentracjach masowych nanocząstek: 0.01%,0.1% oraz 1% na poziomych gładkich rurkach ze stali nierdzewnej i miedzi o średnicy zewnętrznej 10 mm.
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Pool boiling of water-Al2O3 and water-Cu nanofluids on horizontal smooth tubes
PublikacjaPrzedstawiono wyniki badań eksperymentalnych wrzenia dwóch nanocieczy woda-Al2O3 i woda Cu na poziomych gładkich rurkach stalowych i miedzianych. Koncentracja nanoicząstek wynosiła 0.01%, 0.1% oraz 1%.
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A Comparison of Empirical Correlations of Viscosity and Thermal Conductivity of Water-Ethylene Glycol-Al2O3 Nanofluids
PublikacjaBecause of their superb thermal conductivity, nanofluids are seen as new generation of cooling mediums in many engineering applications. It is well established that even a small amount of nanoparticles mixed with a base fluid may result in distinct thermal conductivity enhancement. On the other hand, addition of nanoparticles to the base fluid results in its substantial viscosity increase. Therefore, it is very dicult to evaluate...
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Measurement of temperature-dependent viscosity and thermal conductivity of alumina and titania thermal oil nanofluids
PublikacjaThe results of simultaneous measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of two nanofluids, i.e. thermal oil/Al2O3 and thermal oil/TiO2 are presented. Thermal oil was selected as a base liquid because of possible application in ORC systems as an intermediate heating agent. Nanoparticles were tested at the concentration of 0.1%, 1% and 5% by weight within temperature range from 20°C to...
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MEASUREMENT OF TEMPERATURE-DEPENDENT VISCOSITY AND THERMAL CONDUCTIVITY OF ALUMINA AND TITANIA THERMAL OIL NANOFLUIDS
PublikacjaIn this study results of simultaneous measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of two nanofluids, i.e. thermal oil/Al2O3 and thermal oil/TiO2 are presented. Thermal oil is selected as a base liquid because of possible application in ORC systems as an intermediate heating agent. Nanoparticles were tested at the concentration of 0.1%, 1% and 5% by weight within temperature range from...
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Sessile droplet contact angle of water–Al2O3, water–TiO2 and water–Cu nanofluids
PublikacjaThis work presents measurements of the contact angle of sessile droplets for three nanofluids, i.e. water–Al2O3, water–TiO2 and water–Cu. The plates made of glass, anodized aluminium and stainless steel of different roughness served as substrates. Ultrasonic vibration was used for 30–60 min in order to stabilise the dispersion of the nanoparticles. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight....
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SESSILE DROPLET CONTACT ANGLE OF WATER-Al2O3, WATER-TiO2 AND WATER-Cu NANOFLUIDS
PublikacjaThe goal of the present work was the experimental determination of the contact angle of droplets of three nanofluids on various substrates. Of particular interest was effect of nanoparticle concentration on droplet contact angle.
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Pool Boiling of Water–Al2O3 and Water–Cu Nanofluids Outside Porous Coated Tubes
PublikacjaThis paper deals with pool boiling ofwater–Al2O3 and water–Cu nanofluids on porous coated, horizontal tubes. Commercially available stainless-steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate a test heater. Aluminum porous coatings 0.15 mm thick with porosity of about 40% were produced by plasma spraying. A smooth tube served as a reference tube. The experiments were conducted under different...
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AUGMENTATION OF THE CRITICAL HEAT FLUX IN WATER-Al2O3, WATER-TiO2 AND WATER-Cu NANOFLUIDS
PublikacjaThe main aim of the proposed study is therefore recognition of the phenomena accompanying nucleate boiling crisis of selected nanofluids during boiling on horizontal tubes of various outside diameters. Of particular interest is impact of contact angle and tube diameter on the value of critical heat flux. The results obtained should give more light on the nature of nucleate boiling crisis and will serve as a basis for future theoretical...
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Three-dimensional numerical investigation of hybrid nanofluids in chain microchannel under electrohydrodynamic actuator
PublikacjaEnergy efficiency enhancement methods have received considerable attentionwithin the industry and scientific community, owing to the rising concern ofglobal energy sustainability. The present article attempts to scrutinize the effectsof electrohydrodynamics and nanofluids on the rate of heat transfer and fluidflow in the 3-D chain microchannels. Improved heat exchangers (e.g., chainmicrochannel) would have a key role in increasing...
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The effect of boiling in a thermosyphon on surface tension and contact angle of silica and graphene oxide nanofluids
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Influence of nanoparticle concentration on convective heat transfer of water-Al2O3 nanofluids inside horizontal tubes
PublikacjaThis work presents preliminary results of the experimental investigation of the forced convection heat transfer of water-Al2O3 nanofluids inside stainless steel tube with 8 mm internal diameter and 2000 mm length. Nanoparticles were tested at the concentrations of 0.01%, 0.1%, 1% and 5% by weight and the Reynolds number range encompasses laminar as well as turbulent flows.
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Influence of nanoparticle concentration on convective heat transfer of water-Al2O3 nanofluids inside horizontal tubes
PublikacjaNanofluids came to be seen as a new generation of coolants, especially in single-phase systems. Conducted experiments indicate that the increase in thermal conductivity is not the only reason for the intensification of heat transfer when using nanofluids. Preliminary results of the experimental investigation of the forced convection heat transfer of water-Al2O3 nanofluids inside stainless steel tube with 8 mm internal diameter...
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How the “Liquid Drop” Approach Could Be Efficiently Applied for Quantitative Structure–Property Relationship Modeling of Nanofluids
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Pool boiling heat transfer of water-Al2O3 and water-Cu nanofluids on horizontal stainless steel smooth and rough tubes
PublikacjaPrzedstawiono wyniki badań eksperymentalnych przejmowania ciepła przy wrzeniu nanocieczy woda-Al2O3 i woda-Cu na poziomych rurkach ze stali nierdzewnej. Ustalono, że niezależnie od badanej koncentracji nanocząstek (0.01%, 0.1% oraz 1%) współczynnik przejmowania ciepła dla nanocieczy był wyższy niż dla wody i rósł ze wzrostem koncentracji. Ponadto współczynnik przejmowania ciepła dla nanocieczy wzrastał ze wzrostem ciśnienia.
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The effect of pressure on heat transfer during pool boiling of water-Al2O3 and water-Cu nanofluids on stainless steel smooth tubes
PublikacjaPrzedstawiono wyniki badań eksperymentalnych wrzenia nanocieczy woda-Al2O3 i woda-Cu o koncentracjach nanocząstek 0.01%, 0.1% oraz 1% przy ciśnieniu absolutnym 10 kPa, 100 kPa oraz 200k Pa.
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The effect of pressure on heat transfer during pool boiling of water-Al2O3 and water-Cu nanofluids on stainless steel smooth tube
PublikacjaPrzedstawiono wyniki badań eksperymentalnych wrzenia nanocieczy woda-Al2O3 i woda-Cu o koncentracjach nanocząstek 0.01%, 0.1% oraz 1% przy ciśnieniu absolutnym 10 kPa, 100 kPa oraz 200k Pa.
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Simulation of hybridized nanofluids flowing and heat transfer enhancement via 3-D vertical heated plate using finite element technique
PublikacjaThe present study probed the creation of heat energy and concentrating into Newtonian liquids across vertical 3D-heated plates. The role of the Soret and Dufour theories in concentrating and energy formulas is discussed. The role of hybrid nanoparticles is introduced to illustrate particle efciency in terms of solute and thermal energy. It is removed a viscous dissipation process and a changing magnetic feld. The proposed approach...
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Experimental investigation of free convection of glycol-Al2O3 nanofluid from horizontal tube
PublikacjaNanofluids came to be seen as a new generation of coolants, both in single- and two phase systems. Furthermore, nanofluids or nanocomposites may be used as a media in a thermal energy storage (TES) in such systems as sensible heat storage (SHS) and phase change materials (PCM). In the SHS systems the dominating mechanism of the heat transfer is natural convection. However, in the literature only a few investigations of free convection...
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EXPERIMENTAL INVESTIGATION OF FREE CONVECTION OF GLYCOL-Al2O3 NANOFLUID FROM HORIZONTAL TUBE
PublikacjaNanofluids came to be seen as a new generation of coolants, both in single- and two phase systems. Furthermore, nanofluids or nanocomposites may be used as a media in a thermal energy storage (TES) in such systems as sensible heat storage (SHS) and phase change materials (PCM). In the SHS systems the dominating mechanism of the heat transfer is natural convection. However, in the literature only a few investigations of free convection...