Particle Deposition Characteristics of Supercritical CO2 in a 90° Bend

Abstract

90° bends are widely used in industrial tubes such as supercritical CO2 reactors, which inevitably generate some particle matters during the operation of supercritical CO2 reactors. The particle deposition characteristics in the 90° bend is simulated based on the DPM (Discrete phase model) model. The results show that when the fluid enters the bend, the pressure of the outer wall increases and the pressure of the inner wall decreases due to the centrifugal effect, forming a secondary flow between the inner and outer walls, and forming an obvious low velocity region in the inner wall. As the particle size increases, the deposition rate gradually increases, reaching a maximum at a particle size of 60 μm. Increasing the inlet flow rate first results in a sharp increase in the deposition rate and then a slow increase. The deposition rate is significantly increases with the increasing of wall heat flux due to the thermophoresis effect. The conclusions of this paper can provide reference for the deposition motion characteristics of fine particles in supercritical CO2.