M. Karimi

Publications

3 Interface Location in Single Phase Stirred Tanks

Authors: M. H. Sedaghat, A. Zamani, R. Janamiri, M. Safdari, I. Mahdavi, A. Sinkakarimi, M. Karimi, A. Hoseini

Abstract:

In this work, study the location of interface in a stirred vessel with Rushton impeller by computational fluid dynamic was presented. To modeling rotating the impeller, sliding mesh (SM) technique was used and standard k-ε model was selected for turbulence closure. Mean tangential, radial and axial velocities and also turbulent kinetic energy (k) and turbulent dissipation rate (ε) in various points of tank was investigated. Results show sensitivity of system to location of interface and radius of 7 to 10cm for interface in the vessel with existence characteristics cause to increase the accuracy of simulation.

Keywords: CFD, Interface, turbulence model, Rushton Impeller

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2 CFD Investigation of Interface Location in Stirred Tanks with a Concave Impeller

Authors: M. H. Sedaghat, R. Janamiri, M. Safdari, I. Mahdavi, A. Hosseini, P. Parvasi, A. Sinkakarimi, M. Karimi

Abstract:

In this work study the location of interface in a stirred vessel with a Concave impeller by computational fluid dynamic was presented. To modeling rotating the impeller, sliding mesh (SM) technique was used and standard k-ε model was selected for turbulence closure. Mean tangential, radial and axial velocities and also turbulent kinetic energy (k) and turbulent dissipation rate (ε) in various points of tank was investigated. Results show sensitivity of system to location of interface and radius of 7 to 10cm for interface in the vessel with existence characteristics cause to increase the accuracy of simulation.

Keywords: CFD, Interface, turbulence model, Concave impeller

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1 Staling and Quality of Iranian Flat Bread Stored at Modified Atmosphere in Different Packaging

Authors: M. Karimi, S.A. Mortazavi, A. Hematian Sourki, F. Tabatabaei Yazdi, M. Ghiafeh Davoodi, S.H. Razavizadegan Jahromi, A. Pourfarzad

Abstract:

This study investigated the use of modified atmosphere packaging (MAP) and different packaging to extend the shelf life of Barbari flat bread. Three atmospheres including 70%CO2 and 30%N2, 50% CO2 and 50%N2 and a normal air as control were used. The bread samples were packaged in three type pouches. The shelf life was determined by appearance of mold and yeast (M +Y) in Barbari bread samples stored at 25 ± 1°C and 38 ± 2% relative humidity. The results showed that it is possible to prolong the shelf life of Barbari bread from four days to about 21 days by using modified atmosphere packaging with high carbon dioxide concentration and high-barrier laminated and vacuum bags packages. However, the hardness of samples kept in MAP increase significantly by increase of carbon dioxide concentration. The correlation coefficient (r) between headspace CO2 concentration and hardness was 0.997, 0.997 and 0.599 for A, B and C packaging respectively. High negative correlation coefficients were found between the crumb moisture and the hardness values in various packaging. There were significant negative correlation coefficients between sensory parameters and hardness of texture.

Keywords: correlation, flat bread, modified atmosphere packaging, Iranian bread, staling

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