The tangential velocity and static pressure distribution at the outer wall of vortex finder through a single and a double inlet cyclone were simulated using RSM model.It is shown that the adverse and favorable pressure gradient zone along the outer wall of vortex finder of the double-tangential-inlet cyclone separator is much smaller than that in single-tangential-inlet cyclone separator.The tangential gas velocity around the vortex finder wall has no significant fluctuation and the easy deposit area for oil drip and catalyst is relatively small.There is no stagnant flow area

and the back flow zone near vortex finder wall is not prone to yield.Consequently the probability of coke accumulation on the outer wall of vortex finder of a double-tangential-inlet cyclone is less than that in a single-tangential-inlet cyclone.On the other hand

in double-tangential-inlet separator

the average shearing strength to the coke deposited on the outer wall of vortex finder is large and the average radial pressure grads force is small

which suggests less coking and thinner coke layer on the outer wall of vortex finder.