When the crisscross baffles and logarithmic spiral baffles are placed on the bottom of the stirred tank with elliptic bottom, using CFD software FLUENT simulates the velocity field of the stirred tank with elliptic bottom and bottom baffles. Compare the velocity field of stirred tank with bottom crisscross baffle to the velocity field of stirred tank without bottom baffle and analysis the flow ...

two probiotic bacteria (lb. acidophilus and b. lactis) were immobilized on the alginate coat of strawberry pieces and were added to the prepared sweet non fat dietary stirred yogurt. physico-chemical parameters namely ph value, titratable acidity and synersis along with the viability of probiotic bacteria of the samples were evaluated over the 8 days of storage at 5 ºc at 2 day intervals. a sig...

Experiments Most publications of velocity measurements in stirred tanks concern measurements in single-phase flows. An excellent review of these studies was made by Ranade and Joshi (1990a). Literature concerning velocity measurements in aerated stirred tanks is scarcer however. An overview of literature is given in Table 1. Lu and Ju (1987) used constant temperature anemometry (CTA) in order t...

The relationship between surface transfer impedance and stirred mode chamber shielding effectiveness proposed by Eicher and Boillot has been simplified. This simplified relationship was used to compare the measured stirred mode chamber shielding effectiveness of nine shielding artifacts with the shielding effectiveness of the same samples calculated from transfer impedance measurements made at ...

The formation of acetate by Acetobacterium woodii was studied systematically in batch-operated stirred-tank reactors at different hydrogen and carbon dioxide partial pressures in the gas phase. 48 parallel stirred-tank reactors on a millilitre-scale as well as stirred-tank reactors on a litre-scale were applied for the detailed reaction engineering analysis of hydrogenotrophic acetate formation...

Continuous operation is often chosen for conceptual designs of biological processing of cellulosic biomass to ethanol to achieve higher volumetric productivities. Furthermore, continuous stirred tank reactors (CSTR) can handle higher solids concentrations than possible in batch mode due to broth thinning at partial conversion in a continuous fermentor. However, experience and literature data ar...

Starch acetates of degree of substitution 0.1–1.5 were prepared by heating corn starch, acetic acid and acetic anhydride in sealed, stirred, teflon vessels in a microwave reactor. Reaction efficiencies were typically O90% at reaction temperatures of 150–160 8C for 4–7 min. Starch acetates prepared by reaction at 160 8C to DS values of 0.4–0.9 wereO90% soluble in room temperature water. Acetylat...

Background Currently, stirred tank reactors (STR) represent the gold standard for the large scale growth of suspension cell lines. Culture performance is strongly influenced by the efficiency of mixing, as measured by the mass transfer coefficient and mixing time. The success of traditional stainless steel or glass STR systems lies in their impeller driven agitation that efficiently mixes large...

Abstract We investigate the unsteady forcing of turbulent flow in a well-stirred reactor using opposing arrays pitched-blade impellers which randomly and independently reverse rotation. systematically explore dependence large-scale motions homogeneity isotropy turbulence upon forcing. identify three dimensionless control parameters: source fraction (the time spent clockwise motion), period an i...

The paper presents experimental evidence for the potentials of CFD methodology in revealing external flow and inner flow shear deformation rates in stirred tanks. Two basic issues are considered: could CFD produce valid solutions for shear rates in mixing vessels, and could practical shear rate differences relevant to specific impeller designs be reproduced by CFD. In a first part, the shear ra...