Simulations of flow behavior of oscillatory opposed dilute gas–solid jets

• The impingement zone with high solid volume fraction is formed along the axis of opposed jets.
• The stagnation point where the axial velocities of gas and particles are zero existed.
• The shape of turbulence kinetic energy changes from mushroom, kidney to sandwich.

Flow behavior of gas and particles by means of oscillatory opposed dilute gas–solid mixture jets is presented in this work. Two opposed jets with high velocities of gas-particles mixture are made to oscillate with the same frequency but with a phase shift of π/2. The two opposed jet dilute gas–solid streams are idealization of an array of oscillating opposed jets. Numerical simulations are performed in 3D chamber. The pressure and viscosity of particles and the drag force between gas phase and solid phase are predicted using a commercial FLUENT code. The realizable k–ε model is used to predict turbulence viscosity of gas phase. Flow behavior of gas and particles is investigated with respect to the oscillation frequency of opposed jets. The computational results show that there is an impingement region in the oscillatory flow jets. The solid volume fraction and turbulence kinetic energy of gas phase are high and a stagnation point occurs in the impingement zone. It is shown that the periodic velocities of gas and particles of the opposed jet lead to the horizontal reciprocating movement of impingement zone. The stagnation point with two times frequency of opposed jets oscillates along horizontal reciprocating movement. Further, the analysis shows the large velocities of gas and particles and solid volume fraction in the impingement zone decreases with the increase of frequency of opposed jets. The study shows that low frequency is effective to improve momentum transfer between two opposed jets.

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