No abstract

This paper introduces a new-type of antigravity mixing method, which was applied in the biogas production process, using organic wastewater fermentation. It was found that the digesters with two designs, a highposition, centralized pressure outlet and a high-position, dispersed pressure outlets, both lead to an increase in biogas production rates by 89% and 125%, respectively. The biogas production peak appeared 1 day and 7 days earlier, and the COD removal rates were raised by 27% and 42%, respectively. The results indicated that the optimized flow field had a significant impact. This work also explains the mechanism of flow field optimization using computational fluid dynamics (CFD) software for the simulation of the flow field form in the hydraulic mixing.

The article presents an study on the rheological properties of cement grouts with different water-cement ratios of 0.5,0.55,0.6,0.65,0.7,0.75,0.8,0.9,1.0,1.1,1.25,1.0,2.0,5.0 and10.0.It was to investigate different water-cement ratios of cement grouts effecting its flow pattern properties, and thus determinate the conversion point of them among Newtonian fluid, Bingham fluid and Power-law fluid. It confirmed that,when take into accounts of all negative factors possibly affecting the experiment, including asynchronous loading steps, water temperature, apparatus deflection and so on, W/C(water-cement ratio) = 0.75 is a inflection point,which Power-law fluid converted into Bingham fluid, while at W/C =1.25 the cement grouts suffered a conversion from Newtonian fluid to Bingham fluid. This research results supplied, improved and expanded the knowledge of the flow pattern properties of cement grouts and conversion condition with different water-cement ratios, and so it has important theory meaning and realistic value and may contributes to the engineering practices.

No abstract