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  • Author: Marta Major-Godlewska x
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Marta Major-Godlewska and Dawid Radecki

Abstract

The influence of impellers system and type of liquid on the gas hold-up in the vessel has been presented in this paper. The analysis of gas hold-up was conducted on the basis of the data obtained in the vessel of the diameter D = 0.288 m, where the vessel was filled by a liquid up to the height H = 2D. The vessel was equipped in 24 vertical tubular baffles located on the circuit and two high-speed impellers situated on a shaft. Five different configurations of high-speed impellers were employed. The experiments in the gas-liquid system were conducted for setups which differed in capability of gas bubbles coalescence. The results of the experiment of the gas holdup for the five impellers configurations and four gas-liquid systems were presented in the graphic form and they were described mathematically.

Open access

Marta Major-Godlewska, Marcelina Bitenc and Joanna Karcz

Abstract

The aim of the study presented was to experimentally analyze an effect of the nutrient type and its concentration on the variability of rheological properties of the baker’s yeast suspensions for different time periods. Aqueous suspensions of the baker’s yeast of various concentration (solution I, without nutrient) and yeasts suspended in aqueous solution of sucrose or honey as nutrients with different concentration (solution II or solution III) were tested. Experiments were carried out using rotational rheoviscometer of type RT10 by a company HAAKE. The measurements were conducted for different time periods (from 1 h up to 144 h) at given fluid temperature. On the basis of the obtained data, rheological characteristics of the aqueous solution of baker’s yeast suspensions without and with nutrients of different sucrose or honey concentration were identified and mathematically described.

Open access

Magdalena Cudak, Anna Kiełbus-Rąpała, Marta Major-Godlewska and Joanna Karcz

Abstract

A comparative analysis concerning the influence of different factors on momentum transfer in mechanically agitated systems was carried out on the basis of experimental results for solid-liquid, gas-liquid and gas-solid-liquid systems. The effects of the impeller - baffles system geometry, scale of the agitated vessel, type and number of impellers and their off-bottom clearance, as well as physical properties of the multiphase systems on the critical impeller speeds needed to produce suspension or dispersion, power consumption and gas hold-up were analysed and evaluated.