posted by tiffany .
A patient is to be given a blood transfusion. The blood is to flow through a tube from a raised bottle to a needle inserted in the vein . The inside diameter of the 4.8 cm long needle is 0.48 mm, and the required flow rate is 4.9 cm/3 of blood per minute.
How high should the bottle be placed above the needle? Use pblood = 1.05x10^3 and nblood = 4.0x10E-3 Pa*s. Assume the blood pressure is 18 torr above atmospheric pressure.
I don't understand what nblood is supposed to represent. The units are pressure, but what you need for this problem is a viscosity.
The main flow constriction, where the pressure drop occurs, is the needle. There is a law
(Broken Link Removed)
that relates laminar viscous fluid flow in narrow passages to pressure drop and viscosity. That is what you seem to need for this problem.