APPENDIX 1: CONVERSION OF FLOW RATE TO FLOW VELOCITY
When used with the supplied phantom, which has 3/16” ID tubing, the pump flow rate may be converted to
flow velocity using the conversion chart supplied in the table below. The conversion from flow rate to average
flow velocity is made by dividing the flow rate by the cross-sectional area of the tubing, which is 0.18 cm
2
for
3/16” tubing. For laminar flow, the flow velocity at the center of the tube is double the average flow velocity.
Thus, in constant velocity mode, the maximum flow velocity is double the average flow velocity. In pulsatile
mode, the maximum flow velocity depends on the shape of the pulse profile. Assuming a simple sine wave,
the peak flow velocity will be double the maximum flow velocity in constant velocity mode.
CONVERSION CHART FOR FLOW VELOCITIES
Flow Rate
(ml/s)
Flow Rate
(ml/min)
Average Flow
Velocity (cm/s)
Maximum Flow Velocity:
Constant Velocity Mode
(cm/s)
1
Peak Flow Velocity:
Pulsatile Mode (cm/s)
2
1
60
5.6
11.2
22.5
2
120
11.2
22.5
44.9
3
180
16.8
33.7
67.4
4
240
22.5
44.9
89.8
5
300
28.1
56.1
112.3
6
360
33.7
67.4
134.7
7
420
39.3
78.6
157.2
8
480
44.9
89.8
179.6
9
540
50.5
101.0
202.1
10
600
56.1
112.3
224.5
11
660
61.7
123.5
247.0
12
720
67.4
134.7
269.5
1
Assume laminar flow
2
Assumes simple sine wave pulse