Rheometer

About: Rheometer is a research topic. Over the lifetime, 5759 publications have been published within this topic receiving 125849 citations.

The rheology of cementitious suspensions: A closer look at experimental parameters and property determination using common rheological models

Abstract: This paper investigates the influence of gap between parallel plates, surface texture of the bottom plate, and mixing intensity on the yield stress and plastic viscosity of cementitious suspensions extracted using the Bingham model. Special emphasis is paid toward understanding the effects of shear rate range and different rheological models on the flow parameters. It is shown that the use of a wider shear rate range (0.1–100/s), can be beneficial in obtaining a reasonable portion of the stress plateau in the shear stress–shear rate relationship, which facilitates a model-less, yet accurate extraction of yield stress. The Bingham model that considers only the linear region (i.e. ∼5–100/s) overestimates the yield stress as indicated by the stress asymptote while the Herschel–Bulkley (H–B) equation applied in the 0.1–100/s shear rate range underestimates the yield stress. Further lowering the evaluated shear rate range (i.e. 0.005–100/s) does substantially improve the H–B prediction of yield stress.

Oscillating flow behavior of high‐density polyethylene melts

Abstract: The oscillating flow behavior of a variety of high-density polyethylene and copolymer samples was studied in a constant displacement rate rheometer. At any plunger velocity, the period of the oscillations decreases linearly with melt depth, suggesting a resonance phenomenon. As plunger velocity is increased, the load waveform changes in a regular manner that indicates a progressive increases in the proportion of each cycle spent on the right-hand branch of the flow curve. Little difference was found in the shear stress at which oscillating flow began for samples differing in molecular weight, molecular weight distribution, and manufacturing process. However, the shear rate at which oscillating flow begins depends, strongly on both molecular weight and distribution. Oscillating flow is shifted to higher shear rates by broadening distribution, reducing molecular weight, increasing temperature, or decreasing the L/D ratio of the capillary.

Rheological Characterization of Hydrate Suspensions in Oil Dominated Systems

Abstract: In the work described in this paper, the rheological behavior of hydrate suspensions in an asphaltic crude oil was studied. A P-T cell adapted to operate as a double cylinder configuration rheometer was used. The results obtained show that the hydrate suspensions studied exhibit shear thinning behavior and thixotropy. This behavior is more visible in suspensions with higher particle content and seems to be related to colloidal interactions between the crystals, which causes aggregation between crystals at low shear rates.

Rheological Properties of Banana Puree at High Temperatures

Abstract: The rheological behavior of banana puree was determined using a dynamic stress rheometer with a pressure couette fixture, which allowed experiments to be conducted at high temperature. The pressure couette was pressurized with compressed air to 206.8 kPa (gage pressure) and experiments were carried out at temperatures ranging from 30 to 120°C. The shear stress values ranged from 10 to 170 Pa and the shear rate values from 10−5 to 103 s−1. The model that best fitted the experimental data at all temperatures was the Herschel-Bulkley model. There was a usual tendency for the apparent viscosity to decrease with increasing temperature but an increase in apparent viscosity with increasing from 50 to 60°C and from 110 to 120°C was found. This could be due to interaction of polysaccharides present in banana puree. There was a slight difference between the apparent viscosity values for increasing shear stress sweeps and those for the decreasing shear stress sweeps suggesting time dependency of the rheolog...