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CFD simulation of fluid flow in a novel prototype radial mixed plug-flow reactor
Majid Rasouli,Seyyed Mohammad Mousavi,Hamidreza Azargoshasb,Oveis Jamialahmadi,Yahya Ajabshirchi 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.64 No.-
This research describes a simulation based on three dimensional computational fluid dynamics (CFD) in a semi-continuous PFR reactor. The commercial software FLUENT 6.3 was employed to solve the governing equations. The gas-liquid flow was modeled using an Eulerian multiphase and k–ε turbulence (RNG) model. Hydrodynamics investigated for different total solid (TS) levels and mixing regime using multiple reference frame (MRF) model within the whole multiphase bioreactor. The simulation results in a prototype reactor are validated against the experimental data. Simulation results indicate that flow pattern within the reactor was highly influenced by the substrate density and viscosity, and stirring intensity. Moreover, substrate density and viscosity are variable according to the TS content. The results demonstrate adequate mixing process providing the required amount and intensity of mixing for uniform distribution of reactor content and needed conditions to improve the reactor performance. Comparison of three impeller mixing speed in a reactor demonstrates that mixing intensity has affected the gas phase above the fluid surface. Such a mixing intensity may create a turbulent region with a homogenous mixture of gas and liquid, which is not suitable for this anaerobic digestion.
Adsorption of divalent lead ions from aqueous solution using low silica nano-zeolite X
Milad Rasouli,Mehdi Hafezi,Majid Rasouli,Nakisa Yaghobi 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.6
The studies on adsorption of divalent lead from aqueous solution were conducted by varying various parameters such as contact time, pH, adsorbent dosage, concentration of adsorbate and temperature. The maximum adsorption efficiency was obtained in a contact time of 100 min, pH of 3.5–5, adsorbent dosage of 1.5 g/L, adsorbate concentration of 15 mg/L and temperature of 318 K. The adsorption kinetic of Pb2+onto low silica nano-zeolite X was discussed using different models and the pseudo-second order model provided the best correlation of the experimental data. Langmuir and Freundlich adsorption isotherms were employed in order to evaluate the optimum adsorption capacity of the adsorbent. Low silica nanozeolite X was found to be very effective and reached equilibrium in 100 min. The adsorption capacity of Pb2+ on low silica nano-zeolite X was found to be 909.09 mg/g in the optimum condition. The rate constant and thermodynamic parameters were calculated.
Seismic Reliability of Concrete Buildings Considering Probabilistic Distribution of Crack
Mohammad Safi,Majid Koolivand,Hesamoddin Ketabdari,Mahsa Rasouli 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.1
One of the effective factors in the analysis of concrete structures is consideration of the effect of cracking on the structural elements, which directly affects the calculation of the natural periods, the story displacement and other response parameters. In different codes for design of concrete structures, cracking effect is considered as a mean and constant coefficient for each element, while clearly the condition of various components will be different based on loading situation and specifications. In this paper, reliability of stiffness reduction coefficients of the beams and columns due to cracking of concrete in the ACI code is investigated under random distribution of floor live loads using Monte Carlo simulation method, By considering 1,000 modelling loops, calculating accurate crack coefficients of beams and columns and applying them in each model, the reliability of cracking coefficients has been obtained. The results show that the reliability index of these coefficients is very low. Also, other results of this modeling and applying accurate cracking coefficients show that the story displacements and the time period of first and second modes decrease about 40 − 55% and 20 − 30%, respectively, and the reaction forces of the elements, especially the axial and torsional forces increase about 20 − 30%.