Numerical Simulation Of Flow Characteristic In Self-Priming Venturi Scrubber

Venturi water scrubber is the kernel equipment of in the Filtered Containment Venting System(FCVS)of the nuclear power plant,when the containment is in overpressure accident,it can filter the radioactive products such as gasoloid,iodine and the methyl iodide,in order to protect completeness of the containment and remit accident consequence.So study the flow characteristic of the venturi scrubber is full of great significance.This article study the flow characteristic of two types of vebturi scrubber,integrated-type and split-type,from system parameter and structure parameter by means of numerical simulation,in order to find the influence rule about the scrubbers.The objects of this study are integrated-type and split-type venturi scrubbers.Create the geometric models and mesh them in the software ANSYS ICEM and simulate the flow characteristic of venturi scrubbers in CFD FLUENT.Verify the mesh independence and the mesh reliability and determine the two-phase flow model and turbulence model which are suitable for the simulation of flow characteristic in venturi scrubbers.In the structure parameter,when the field angle of expansion section in split-type venture scrubber is between 3° and 6°,it can get the ideal liquid injection flow rate;the existence of mixing section in the split-type venture scrubber can decrease the liquid injection flow rate,and the longer of mixing section,the lower liquid injection flow rate can get.The area ratio in the split-type venturi scrubber has a great influence on liquid injection flow rate.When area ratio is low,the liquid injection flow rate increases rapidly while the ratio rises,when ratio is large,the liquid injection flow rate shows a decline while area ratio increases.For the integrated-type venturi scrubber,when the system pressure is in the pressure level is constant,the higher position of the ejector pipe in throat section,the larger liquid injection flow rate can get.When the amount of ejector pipes is constant,set pipes of the throat section in multiple rows can contribute to increasing liquid injection flow rate.In the system parameter,the mass flow rate of gas in the entrance of venturi scrubbers has different influences on the integrated-type and split-type venturi scrubbers.For the integrated-type venturi scrubber,when scrubbing solution's liquid level is low,the liquid injection flow rate of the first row is in growth after a decline,and the other four rows pipes' liquid injection flow rate raises linearly with the increase of mass flow rate on the entrance of the venturi scrubbers;for the split-type venturi scrubbers,when the scrubbing liquid's liquid level is low,liquid injection flow rate raises linearly with the increase of mass flow rate of the gas,when the liquid level is high,liquid injection flow rate of the scrubber has been reduced and get a gentle add ultimately with the increase about gas mass flow rate.The system pressure has the same influence on the two types of scrubbers.Increasing the system pressure can make a constribute to the increase of liquid injection flow rate both on integrated-type and split-type scrubbers.The liquid level of scrubbing solution has partition effects on the liquid injection flow rate,when the mass flow rate of gas is low,liquid level has significant effect on liquid injection flow rate,and in this case,we can get higher liquid injection flow rate than any other liquid level while large mass flow rate of gas can reduce the impact,and with the increasing of the liquid level,its influence on the liquid injection flow rate can be ignored.When study the pressure drop of venture scrubbers,we found that the greater degree of expansion section,the longer mixing section and the larger area ratio can bring lower pressure drop between inlet and outlet of venture scrubbers.