抄録
The magnetic field of the electromagnetic flowmeter, which is now used practically, is usually uniform. This type of flowmeter is able to measure any flow rate very accurately as long as the velocity distribution of flow is axially symmetrical. But the sensitivity of this flowmeter varies very greatly as a function of the velocity distribution when the flow velocity is axially non-symmetrical.
The author previously described that the error caused by the axially non-symmetrical flow is made very small when the magnetic field of the flowmeter is suitably distributed.
In this paper, the distribution of the sensitivity in the cross-sectional area of the probe is discussed theoretically and experimentally for various types of probes. One of these probes is suitable for measuring the axially non-symmetrical flow. The sensitivity of this probe varies less than ±6% over most of the cross-sectional area. This value of sensitivity change is about one third of that which is obtained by the uniform magnetic field probe.
The velocity distribution of blood flow, especially in the proximal aorta, is axially nonsymmetrical. This probe is very useful for measurement of such a flow because not only is the sensitivity change very small but also the probe itself con be very small.
