the question of flow velocity in she solar field

I want ask one question: which are the detailed restrictions of field flow velocity? what is the number of the min field flow velocity or max? Thanks .

For the physical trough model, SAM calculates the minimum and maximum field flow velocities using the following equations:

Min Field Flow Velocity = ( Min Single Loop Flow Rate x 4 ) /
( HTF Density at Field Output * pi
* (Absorber Tube Inner Diameter)^2 )

Max Field Flow Velocity = ( Max Single Loop Flow Rate x 4 ) /
( HTF Density at Field Output * pi
* (Absorber Tube Inner Diameter)^2 )

I have added these and other equations to the physical trough model Help topics that will be included in the next update to SAM 2012.5.11.

Best regards,
Paul.