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1

Cavitation erosion of P110 steel in different drilling muds

Kmieć M., Karpiński B., Szkodo M.

Advances in Materials Science

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2016

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Vol. 16, nr 2(48)

57--67

EN

The P110 steel specimens were subjected to ultrasonic cavitation erosion in different compositions of drilling muds and surfactant additive. The test procedure was based on ASTM-G-32 standard recommendations. API 5CT-P110 steel is used for pipes in oil and gas industry. The harsh environment and high velocity of flows poses corrosive and erosive threat on materials used there. The composition of drilling fluid influences its rheological properties and thus intensity of cavitation erosion. The erosion curves based on weight loss were measured.

2

Numerical simulation of blade-over-roll coating forming flows

Mitsoulis E., Athanasopoulos G.

Computer Methods in Materials Science

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2010

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Vol. 10, No. 4

214-224

EN

Numerical simulations have been carried out via the finite element method (FEM) for the forming flow of coating using a system of blade and roli. The flow domain encompasses both the coating fluid reservoir and the doctor-blade region with free surface and is fully two-dimensional. The materials of this study are Newtonian and shear-thinning polymer solutions used previously in an experimental and theoretical investigation. The pseudoplasticity of the polymeric liquids is modelled by the Carreau model, which fits well experimental data for the shear viscosities. For different roll speeds, the entire flow domain is analyzed, and the extent and shape of recirculating zones are found. Large vortices appear in the reservoir, and their intensity is computed under different operating conditions and blade geometries. The computed free surface profiles and coating thicknesses arę in close agreement with the experimental ones. Shear thinning increases the coating thickness for a given geometry, as was also found experimentally, when compared with the Newtonian values. This increase is valid up to power-law index n great than 0.3, while extreme shear-thinning (power-law index n less than 0.3) reduces the coating thickness. This new finding is in agreement with previous findings in other geometries for highly shear-thinning fluids. The vortex decreases in size and intensity monotonically and linearly with n, in the range 1 greater-than or equal to n greater than 0. The simulations also provide a wealth of information regarding stresses and pressures and show that some geometries are better than others in coating operations. The flow geometry provides an interesting case for simulation and design, due to a combination of fluid mechanics and shear-thinning phenomena that take place in this flow field.

3

Flow properties of soft cheese type Fromage frais

Zander L., Zander Z., Haponiuk E.

Applied Mechanics and Engineering

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1999

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Vol. 4, no spec.

461-466

EN

Flow properties of soft cheese type Fromage frais were obtained using standard coaxial cylinder system and resulting from measurements torque on the shaft of the rotating 4-blade vane immersed in the fluid tested. The rheological characterisation was performed as a function of temperature varied from 10 to 65oC. The 'static' yield stress of the material tested was also determined by so-called 'vane method'. The shear stress - shear rate data were approximated using power-law, Casson and Herschel-Bulkley models. Further discussion was performed with respect to temperature effect on the rheological parameters by matching the Arrhenius type equations.