Date of Award

Fall 1972

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Electrical and Computer Engineering

First Advisor

Linehan, John, H.

Second Advisor

Sances, Anthony

Third Advisor

Elkouh, A. F.


In the last twenty-five years since the discovery of nuclear magnetic resonance (NMR) phenomena, NMR detection techniques have been used in many areas of technology. The NMR flowmeter is one of the important applications. The principal components of the NMR flowmeter are the upstream magnetizer and the downstream detector. The liquid is magnetized as it flows through the magnetizer and the level of magnetization is detected downstream by the detector. The amplitude and the shape of the detected signal is related to the flowrate. The entire process is non-intrusive to the detected liquids. Blood flow measurement using NMR techniques is the subject of research in several countries at the present time. Encouraging results have been obtained by the Laboratory of Technical Development at NIH and by the Medical College of Wisconsin. A five-cm internal diameter flowmeter has been tested for measuring blood flow in the upper and lower limbs of monkeys and dogs and also the arm of small children. A ten-cm internal diameter cylindrical NHR flowmeter is presently being designed and constructed to measure limb blood flow in adults. A complete transport theory for the magnetization in a flowing liquid in pulsatile flow has not been published. In this thesis, a theoretical model was developed to describe the transport of magnetization in a flowing liquid in pulsatile flow. It was found that convective effects dominate and that self-diffusion is negligible. The predictions of the theoretical model were compared with in-vitro experimental data. The predictions were in good agreement with the data for straight tube, tapered tube, and bifurcated tube test sections. In addition, it was shown that the theoretical model is useful in evaluating the effects of system parameters and can be used, therefore, in optimizing the design of the flowmeter. Computer simulation of the ten-cm internal diameter NMR flowmeter yielded very encouraging results. Using typical dimensions of the major arteries of the arm, the output of the flowmeter was shown to increase monotonically with increasing limb flowrate.



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