List of Articles Stirred tank

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  1 - Investigating the speed and geometry of the mixer on the flow distribution in an industrial reactor
  Seyed mohammad hasan Mousavizadeh Mahdi Hamzehei
  In this project, a three-dimensional investigation of the fluid flow inside a stirred tank inside an industrial reactor has been done to investigate the velocity distribution and heat transfer. To model the stirred tanks and its blades, first the geometry structure was More

  In this project, a three-dimensional investigation of the fluid flow inside a stirred tank inside an industrial reactor has been done to investigate the velocity distribution and heat transfer. To model the stirred tanks and its blades, first the geometry structure was carefully studied, then the geometry modeling was done using SOLIDWORKS software, then the generated geometry was entered into the Ansys Space claim or Ansys Design Modeler software. After that, meshing is done with Ansys Meshing software, and then appropriate boundary conditions are applied on the stirred tank and its blades. In this project , SST , k-ω turbulence model is used. For meshing, unorganized mesh generation was used, and the average mesh quality, aspect ratio, and elongation for the computational mesh of the tank with an anchor agitator were 0.84, 1.84, and 0.22, and also the flow field inside an agitator tank with a baffle was For the angular speeds of 60 , 120 and 180 rpm , it was simulated for two types of stirrers. By increasing the angular speed of the propeller, the performance of mixers improves and better mixing takes place. Examining the velocity vectors showed that four strong wake regions were formed near the impeller, and two rings were formed on each side, one at the bottom and the other at the top of the stirrer. The first jet circulates to the bottom of the tank and then returns to the propeller area. The second fluid jet also circulates in the upward direction. In the new mixer, there are more high-speed areas in the distance between the bottom of the tank and the impeller compared to the anchor mixer. In fact, the speed is almost twice that of the anchor stirrer. Therefore, the new agitator has a much better performance than the anchor agitator in the bottom areas of the tank. So, the new mixer has a better performance for mixing solid materials that have the possibility of sedimentation. At distances farther from the bottom of the tank, the tank with the anchor stirrer has better mixing than the new stirrer , and this anchor stirrer has more high-velocity areas than the new stirrer. In the new high-speed mixer, the distance between the bottom of the tank and the propeller is greater than that of the anchor mixer. In fact, the speed is almost 2 times that of the anchor stirrer. Therefore, the new stirrer is much better than the anchor stirrer in the bottom areas of the tank. So, the new mixer has a better performance for mixing solid materials that have the possibility of sedimentation. At distances farther from the bottom of the tank, the tank with the anchor stirrer has better mixing than the new stirrer, and in these areas the anchor stirrer has a higher speed than the new stirrer. At a height of y = 0.880 m meters of fluid is divided into four symmetrical jets and the rest of the fluid flows upwards and reaches the free surface , and the speed increases with the height until reaching the height y = 1.330 m , where the length of the vortices decreases and circulates from the impeller to the impeller shaft due to the pumping effect . The speed of the fluid flow in the tank that is stirred by the new propeller is much higher than that of the anchor propeller , so the mixing time with the new propeller is less than that of the anchor propeller. Manuscript profile
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  2 - Pilot Plant Production of Lactic acid by Lactobacillus casei subsp. casei
  S.S Mirdamadi
  The aim of present study, was to scale up the production of L (+) lactic acid from the laboratory to pilot plant using Lactobacillus casei subsp. casei PTCC 1608. Moreover, the minimum inhibitory concentration of the produced lactic acid and sodium lactate against 4 tes More

  The aim of present study, was to scale up the production of L (+) lactic acid from the laboratory to pilot plant using Lactobacillus casei subsp. casei PTCC 1608. Moreover, the minimum inhibitory concentration of the produced lactic acid and sodium lactate against 4 test strains including Staphylococcus aureus PTCC 1113, Microccoccus luteus PTTC 1110, Escherichia coli PTCC 1330 and Listeria monocytogenes PTCC 1304 were evaluated. According to the results, the specific growth rate of each test strain was decreased by lactic acid. The inhibitory effect of the sodium lactate was lower than lactic acid in all of the experiments. The best carbon (glucose, lactose and whey) and nitrogen (corn steep powder) sources were optimized in batch and fed batch system and also pH, temperature and aeration were improved in shake flask incubator, 20 l and 750 l stirred tank reactors (STR). Glucose (80 g/l) supplemented with (50 g/l) whey was found as the best production medium.Productivity and yield of calcium lactate production in laboratory scale were 0.51 g/lh and 0.56%, respectively. Fed batch production of calcium lactate in 20 l bioreactor increased the productivity and yield up to 2.47 and 0.83%. Production and productivity was increased up to 350 g/l and 5.4 g/lh, respectively in scaled up processes by 750 liters bioreactor (STR). Manuscript profile
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  3 - Design of Fault Tolerant System Using Model Predictive Control and Model-Based Fault Identification for a Chemical Reactor
  Mehrdada Raeiisi Seyed Mohammad Kargar Dehnavi
  Due to the possibility of fault in any industrial system's actuators, using a fault-tolerant control structure to compensate for the fault and maintain the system stability seems necessary. In this paper, the Continuously Stirred Tank Reactor model is evaluated, which h More

  Due to the possibility of fault in any industrial system's actuators, using a fault-tolerant control structure to compensate for the fault and maintain the system stability seems necessary. In this paper, the Continuously Stirred Tank Reactor model is evaluated, which has a nonlinear model with temperature outputs and heating inlets of interconnected tanks. An Unscented Kalman filter is used to estimate the model's output dynamics, which has a suitable convergence speed and higher accuracy than other estimators. The nonlinear predictive control approach is used to apply the appropriate heating rate to the system to achieve the desired temperatures for each tank when there is no fault in the system. In the proposed design, to compensate for the fault, a sliding mode observer has been used to identify the fault. When a fault is detected, a fuzzy proportional derivative controller is used to control the system's fault. MATLAB software has been to evaluate the proposed method in different working modes of the reactor model. The simulation results show the good performance of the proposed method to compensate for the fault Manuscript profile
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  4 - Evaluation of two lattice Boltzmann methods for fluid flow simulation in a stirred tank
  SeyedMehdi Naghavi
  In the present study, commonly used weakly compressible lattice Boltzmann method and Guo incompressible lattice Boltzmann method have been used to simulate fluid flow in a stirred tank. For this purpose a 3D Parallel code has been developed in the framework of the latti More

  In the present study, commonly used weakly compressible lattice Boltzmann method and Guo incompressible lattice Boltzmann method have been used to simulate fluid flow in a stirred tank. For this purpose a 3D Parallel code has been developed in the framework of the lattice Boltzmann method. This program has been used for simulation of flow at different geometries such as 2D channel fluid flow and 3D stirred tank fluid flow. It has been shown that in addition to elimination of compressibility error, the Guo incompressible method eliminates mass leakage error from the fluid flow simulations although its implementation is as easy as the weakly compressible Lattice Boltzmann method. By the way, comparison between results of the two methods shows that differences in local flow quantities are negligible in both methods; however, for overall flow quantities, the results of Guo incompressible method are more accurate than those of weakly compressible method. Manuscript profile