[sarsam.9296]

I am working on a helical coil heat exchanger ( Tube side : Helical coil and Shell: cylindrical)

For solving the temperature profile in Fluent, which model should I use:

Case -1: Both shell side and tube side flow is laminar. But as we know, secondary flow develop in helical coil due to centrifugal force. Because of these secondary flow should I use k-epsilon model or laminar model.

Case-2: Shell side flow is turbulent and tube side is laminar. Which model should I use, K-epsilon or laminar.

Case-3: Is there any way I can define different models for different flow patterns on tube side and shell side.

please reply

[ghost82]

Originally Posted by sarsam.9296

I am working on a helical coil heat exchanger ( Tube side : Helical coil and Shell: cylindrical)

For solving the temperature profile in Fluent, which model should I use:

Case -1: Both shell side and tube side flow is laminar. But as we know, secondary flow develop in helical coil due to centrifugal force. Because of these secondary flow should I use k-epsilon model or laminar model.

Case-2: Shell side flow is turbulent and tube side is laminar. Which model should I use, K-epsilon or laminar.

Case-3: Is there any way I can define different models for different flow patterns on tube side and shell side.

please reply

Hi, I would go for laminar as a first try (both, shell and tube, case 1); you can then switch on k-epsilon for the tube side (RNG could be a good choice) and compare results.
Or you can use a transitional turbulent model, but take care to y+ values.
Case2: turbulent in shell and laminar in tube; same comment as above for the tube zone.

It is possible to simulate one zone with laminar model and one zone with a turbulent one.
Make 2 zones (shell and coil) in pre-processor, then in fluent, choose a turbulent model, but in cell zones, for the laminar zone, check the laminar box.

Daniele

[supriyamishra39]

can u plzz tell me how to draw the helical shape tube in ansys dm..

plzzz reply..

[fresty]

Though you would find many tutorials for this and procedure might not differ from other 3D CAD softwares; however, generally you could draw a desired 3D (sketch) helix profile (originating from global origin) and a circle (or any planar shape that you would like) on either of the ends with it's centre at the termination of the 3D helix line.. sweep the circle while selecting the helix line as the path..