| The gas-liquid reactor is used in the chemical industry, stirred reactor is one of them. The traditional way of mixing is mechanical stirring. The principle of mechanical stirring is the liquid which in the reactor stirred by shaft and impellers, and rotated in a stirred tank.For the gas-liquid mixing, evaluate its performance including various of factors. From a macro point of view, containing stirring power and average gas holdup; From the microscopic point of view, containing two-phase flow pattern, the local gas holdup, bubble size and other factors. If a stirred tank has reaction or heat transfer and other more complex phenomenon, also need to consider the influence of the gas-liquid interfacial area, the volumetric mass transfer coefficient. In this paper, we mainly considerate the influence of speed, volume, impeller type, impeller spacing, gas sparger diameter for gas-liquid effect.The paper by means of CFD numerical simulation, study gas-liquid flow of stirred reactor, and get simulation results compared with experiment data. This paper selects the main fluid is glycerin water solution viscosity of 0.12Pa·s, besides, glycerin water solution viscosity include water,0.01 Pa·s and 0.05 Pa·s. The results were obtained as follows:For the impeller type selection, this paper selects two kinds of impeller types, respectively is InterMigDU and InterMigUD, for the power consumption and the average gas holdup, InterMigUD has more advantages, InterMigUD has small power consumption large mean gas holdup, but from the aspect of average bubble size and interfacial area to analyze, the average bubble size of InterMigDU is smaller than InterMigUD, and the volumetric mass transfer coefficient is greater than InterMigUD.We select three kinds of layer spacing, respectively is 0.36D,0.5D and 0.69D. Due to the overall level is 710mm, the paper consider the Δ/D shouldn’t requires a combination of the height and the liquid level, the spacing of layers for the 0.36D which has the high volumetric mass transfer coefficient, the gas holdup located the middle of three of them and uniformity of the bubble sizes is the best. The interlayer spacing of 0.5D, the overall gas holdup is the top of them, the volumetric mass transfer coefficient and bubble size uniformity is slightly less than 0.36D.For the different diameter of as distributor s concerned, this paper has selected five kinds of different diameters of the gas distributor, respectively is 0.3T,0.4T,0.55T,0.65T,0.75T. Found that with the increase of the diameter of the gas distributor, gas-liquid mixing effect is better and better, the overall gas holdup also increas, the uniformity is good, the volumetric mass transfer coefficient increases. Therefore, the gas-liquid mixing, properly increasing the diameter of gas distributor is good.This paper selects water and thre glycerin water solution, with water as a basis for comparison, found that with the increase of fluid viscosity, power consumption increase, overall gas holdup also showed an increasing trend, the average bubble size get large, the volumetric mass transfer coefficient decreases, he range of simulation are all in turbulence, o the flow pattern of the liquid phase doesn’t change a lot.Some numerical results are compared with experimental data, and fit well. So the simulation method is used to calculate the other conditions, and considering the simulation method can be extended to similar viscoelastic system, provide a reference for industrial production. |
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