Generation, dynamic flow reactor

Reactors which generate vortex flows (VFs) are common in both planktonic cellular and biofilm reactor applications due to the mixing provided by the VF. The generation of Taylor vortices in Couette cells has been studied by MRM to characterize the dynamics of hydrodynamic instabilities [56], The presence of the coherent flow structures renders the mass transfer coefficient approaches of limited utility, as in the biofilm capillary reactor, due to the inability to incorporate microscale details of the advection field into the mass transfer coefficient model. 

Solverg, K. O., and P. Bakstad, 1967, A Model for the Dynamics of Nuclear Reactors with Boiling Coolant with a New Approach to the Vapor Generation, Proc. Symp. on Two-Phase Flow Dynamics at Eindhoven, EURATOM Rep. (6)... 

The non-linear dynamics of the reactor with two PI controllers that manipulates the outlet stream flow rate and the coolant flow rate are also presented. The more interesting result, from the non-linear d mamic point of view, is the possibility to obtain chaotic behavior without any external periodic forcing. The results for the CSTR show that the non-linearities and the control valve saturation, which manipulates the coolant flow rate, are the cause of this abnormal behavior. By simulation, a homoclinic of Shilnikov t3rpe has been found at the equilibrium point. In this case, chaotic behavior appears at and around the parameter values from which the previously cited orbit is generated. 

In some situations the dynamics of the cooling system may be such that effective temperature control cannot be accomplished by manipulation of the coolant side. This could be the situation for fluidized beds using air coolers to cool the recirculating gases or for jacketed CSTRs with thick reactor walls. The solution to this problem is to balance the rate of heat generation with the net rate of removal by adjusting a reactant concentration or the catalyst flow. Such a scheme is shown in Fig. 4.24. 

The first method is a sure way to expose the surface of powder uniformly if one pass is sufficient to achieve the surface modification, but it is not easy to recycle the substrate in the luminous gas phase in vacuum. Therefore, the main issue in this approach is how to repeat the interaction of surface with the luminous gas phase efficiently, which entirely depends on the flow dynamics of powders. Multiple-step operation requires multiple discharge systems or repeated operation. The generation of discharge is more or less the same as the conventional modes used in LCVD reactors. External radio frequency electrodes or coil with glass tube is the most... 

Fig. 4.2. Flow injection manifold for automatic hydride generation. 1-3 Points at which the stripping gas may be inserted into the dynamic system, P peristaltic pump, IV injection valve, R reactor, GLS gas-liquid separator, D detector, W waste.

Computational fluid dynamics based flow models were then developed to simulate flow and mixing in the loop reactor. Even here, instead of developing a single CFD model to simulate complex flows in the loop reactor (gas dispersed in liquid phase in the heater section and liquid dispersed in gas phase in the vapor space of the vapor-liquid separator), four separate flow models were developed. In the first, the bottom portion of the reactor, in which liquid is a continuous phase, was modeled using a Eulerian-Eulerian approach. Instead of actually simulating reactions in the CFD model, results obtained from the simplified reactor model were used to specify vapor generation rate along the heater. Initially some preliminary simulations were carried out for the whole reactor. However, it was noticed that the presence of the gas-liquid interface within the solution domain and inversion of the continuous phase. 

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