Follow the steps below...
Using front plane to sketch a circle, 200mm in Dia. and extrude it according the setting as shown...
Sketch a circle on the front plane that snap with the inner circle of the tube (same Dia. with inner circle).....and exit sketch~
Click on the "Helix and Spiral" under the Curves command, and select the circle that you had sketched just now.....Next, follow the setting bellow, and OK with it~
Sketch a point on front plane as a reference...and follow the next step~
...sketch as the pic. shown
Click on Swept-cut, and follow the setting bellow...
Next click on the "Axis" under Reference Geo. command....and follow the setting as shown...
Click on Circular Pattern and follow the setting....