Hello dear experts,
I am currently running a CFD calculation on turbulent flow inside a pipe with a tight-fit twisted tape. For velocity inlets of 1m/s and 0.4 m/s, the solution converges, and the fully-developed flow occurs. However, for velocities in between (eg. 0.6 and 0.8 m/s) the convergence does not occur. the fluid is a mixture of EG and water which was considered as one fluid with constant properties, which are:
C_p=3611.2037
pho=1032.16
mu=0.0054121
k=0.4956
the geometry is a 2 m long pipe with twisted tape and the pipe diameter is 1cm. the twist ratio is 5. the solver is SST k-omega.
It would be very kind of you if you could walk me through this problem.
kind regards,
Mahyar SeydEshaghi
hello Ali Karimi
The area averaged y+ for the cases are as follows:
1)
inlet velocity 1 m/s:
y+ on twisted-tape: 0.705779
y+ on pipe wall: 0.75652
2)
inlet velocity 0.4 m/s:
y+ on twisted-tape: 0.382025
y+ on pipe wall: 0.402024
Dear Yavar Karimi ,
from my perspective, Due to the 3D boundary layer, sweeping velocity, the k_epsilon method cannot produce a viable result since it uses the preassumed gradients close to the walls.