دانلود رایگان مقاله انگلیسی روش پیش بینی ویسکوزیته سرباره زغال سنگ: تاثیر مورفولوژی ذرات بر ویسکوزیته تعلیق - الزویر 2018

ABSTRACT

Viscosity is the key factor affecting the flowability of molten coal slag in the entrained flow gasifier. The volume fraction and morphology of solid phase in slag are important factors affecting the slag viscosity. In this study, the malt syrup and the particles with different sizes and morphologies were chosen as the simulation medium to study the effect of particle morphology on the suspension viscosity. The influences of size, shape and aspect ratio of solid particles on the suspension viscosity were considered. It was concluded that the suspension viscosity increased with the decrease of the particle size. The suspension viscosity increased with the increase of the aspect ratio of the particles. This phenomenon was more obvious under the high volume fraction of solid phase. With the same size and aspect ratio, the non-spherical particles had greater effect on the suspension viscosity than spherical particles. A correction factor was used to modify the viscosity model with the consideration of particle size, shape and aspect ratio. The prediction results of new modified viscosity model of the suspension finally showed good agreement with the measured experimental data.

4. Conclusion

In this paper, the factors that affect the suspension viscosity were mainly studied, including the particle size, shape and aspect ratio of the solid particles. The Einstein-Roscoe equation was modified on the basis of a series of experimental data, and the model of the suspension viscosity respecting to the solid phase volume fraction was obtained. The conclusions are as follows:

(1) The suspension viscosity increased with the decrease of the particle size under the same volume fraction of particles, and the suspension viscosity increased more obviously under the high solid phase volume fraction.

(2) Particle shape also had effects on the suspension viscosity, and the effect of the non-spherical particles on the suspension viscosity was larger than that of the spherical particles

(3) The suspension viscosity increased with the increase of the particle aspect ratio, and the larger the aspect ratio, the more the suspension viscosity increased.

(4) Based on the influence of three factors, the equation of suspension viscosity respecting to the solid phase volume fraction was obtained, and the prediction results of the suspension viscosity agreed with the experiment data. However, this paper simplify the influence of maximum packing fraction and shear rate on the suspension viscosity which would be studied in future work.