Flow Field Analysis And Performance Study Of An Axial Flow Vane-type Degasser

Axial guide vane separators have important applications in the industrial field due to their advantages such as good separation efficiency,low pressure loss,small footprint,and easy maintenance.In this paper,the effects of the guide vane structure and exhaust method in the axial flow degasser on the flow field,pressure drop,degassing efficiency,and liquid entrainment rate in the separation tube were explored by combining numerical simulation and experiments The morphological changes.The simulation results show that the flow field in the deaerator is in the form of Rankine vortex,that is,the external quasi-free vortex and the internal quasi-forced vortex.The guide vane structural parameters affect the flow field distribution,pressure drop and degassing efficiency in the separation tube.Compared with the experimental value,the simulated value of the degasser pressure drop is less than 10%,showing good consistency.Reducing the number of blades,blade wrap angle,and hub diameter,and increasing the outlet angle are conducive to a smaller separator pressure drop,while the exhaust hole diameter has less effect on the pressure drop.At the same processing capacity and the same outlet pressure,the pressure drop of the mixed flow exhaust method is equivalent to the pressure drop of the upforward flow exhaust method,and the pressure drop of the upstream exhaust method is higher.Increasing the number of blades,wrap angle,hub diameter and exhaust hole diameter,reducing the blade exit angle is beneficial to improve the separation efficiency;the exhaust method also affects the degassing efficiency,where,The mixed-flow exhaust method has the highest degassing efficiency,followed by the upstream exhaust,and the downstream exhaust;.The bubble particle size also affects the degassing efficiency,and bubbles with a larger particle size are more easily removed.The experimental results show that the exhaust method and the outlet pressure have an important influence on whether the gas column can be formed and the liquid entrainment rate.For the conditions of co-flow exhaust and mixed-flow exhaust,when the outlet pressure reaches the critical separation pressure,a stable Air column,the degassing efficiency can reach 95%,and the upstream exhaust cannot form a stable air column;the liquid entrainment rate increases with the increase of the outlet pressure,and shows a downward trend with theincrease of the processing volume;The upstream exhaust entrainment rate is the lowest,and the mixed flow exhaust entrainment rate is the highest.When the outlet pressure is not higher than 40 kPa,the entrainment rate does not exceed 10%.