Thank you so much for your reply!
I didn’t describe the problem clearly, sorry.
I meant that the high-temperature gas enters from the bottom gas_inlet and is discharged from the top gas_outlet; The particles are injected from the top particle_inlet, and after a certain period of time, the top particle_inlet stops injecting new particles, while the existing particles automatically enter from the top particle_inlet to form a cycle when they move to the bottom of the reactor.
