Topic
Rheometer
About: Rheometer is a research topic. Over the lifetime, 5759 publications have been published within this topic receiving 125849 citations.
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TL;DR: In this paper, a new model for viscosity decay at constant shear rate is tested and the thixotropic behavior of representative food products is experimentally analyzed, which is well represented by the Herschel-Bulkley model and by an exponential model in which a maximum of two terms of an infinite series are required.
Abstract: In this work, a new model for viscosity decay at constant shear rate is tested and the thixotropic behavior of representative food products is experimentally analyzed. The equilibrium viscosity (or steady‐state viscosity) of some food products, obtained after a sufficiently long time of shear at a constant shear rate, is found to be well represented by the Herschel‐Bulkley model and by an exponential model in which a maximum of two terms of an infinite series are required. The model for viscosity decay, that is, the decrease in viscosity with time at constant shear rate, assumes nth order kinetics for the decay of a structural parameter λ. The rate constant k, for the decay of λ, is found to be a power law function of the shear rate. The equation for structure decay is combined with a scalar constitutive equation for the shear stress and the resulting model represents adequately the data for viscosity decay of foodstuffs in the range of shear rates 50<γ<5420 s−1. Data for suspensions such as tomato juice...
98 citations
TL;DR: In this article, the authors investigated the rheology of high internal phase ratio oil-in-water emulsions using a controlled-stress rheometer and found that yield stress and storage modulus increased with the increase in the dispersed phase concentration and with the decrease in the average droplet size.
98 citations
TL;DR: In this paper, the wall and Reynolds shear stresses were measured using a hot-film anemometry technique, and the predicted interfacial shear stress data were approximated by the formula relating the interfacial friction factor with the void fraction and gas and liquid Reynolds numbers, and were compared with other reported data.
Abstract: Experimental values are presented for the wall and interfacial shear stresses in stratified gas-liquid flow in a pipe. The wall and Reynolds shear stresses were measured using a hot-film anemometry technique. The interfacial shear stress was determined using two methods: from a momentum balance, using the wall shear stresses and void fraction measurements, and from an extrapolation of the Reynolds shear profile at the gas-liquid interface. The predicted interfacial shear stress data were approximated by the formula relating the interfacial friction factor with the void fraction and gas and liquid Reynolds numbers, and were compared with other reported data.
98 citations
TL;DR: In this article, an alternate mechanical test to the bending beam rheometer (BBR) was proposed to determine low-temperature PG using 4mm-diameter parallel plates on a dynamic shear rheometry (DSR) and includes a correction for machine compliance.
Abstract: Mechanical measurements on asphalt binders to determine the performance grade of the low-temperature specification are typically carried out with a bending beam rheometer (BBR). The BBR test requires considerable material to fabricate a specimen (approximately 15 g per beam). The relatively large amount of asphalt binder required for the BBR limits its applications. The BBR is difficult to apply to extracted asphalt binder or to other situations in which there is a limited amount of binder, for example, residue from emulsions. This paper proposes an alternate mechanical test to the BBR to determine low-temperature PG. Only approximately 25 mg of asphalt binder are required to perform a test. The test employs 4-mm-diameter parallel plates on a dynamic shear rheometer (DSR) and includes a correction for machine compliance. This correction allows testing to -40°C. A low-temperature specification from the 4-mm rheometry is suggested by the establishment of a correlation between BBR creep stiffness data and DS...
97 citations
TL;DR: In this paper, thermal conductivity and viscosity of the Al2O3/polyalkylene glycol 46 nanolubricants for 0.05 to 1.0% volume concentrations at temperatures of 303.15 to 353.15 K have been investigated.
Abstract: In this paper, thermal conductivity and viscosity of the Al2O3/polyalkylene glycol (PAG) 46 nanolubricants for 0.05 to 1.0% volume concentrations at temperatures of 303.15 to 353.15 K have been investigated. Al2O3 nanoparticles were dispersed in the PAG lubricant by a two step preparation. The measurement of thermal conductivity and viscosity was performed using KD2 Pro Thermal Properties Analyzer and LVDV-III Rheometer, respectively. The results showed that the thermal conductivity of the nanolubricants increased by concentration, but decreased by temperature. Besides, the viscosity of the nanolubricants sharply increased for concentrations higher than 0.3%. However, this parameter diminished by temperature. The highest thermal conductivity and viscosity ratio were observed to be 1.04 and 7.58 times greater than the PAG lubricant for 1.0% and 0.4% concentrations, respectively. As a conclusion, it was recommended to use the Al2O3/PAG nanolubricants with concentration of less than 0.3% for application in automotive air conditioning system.
97 citations