Optimal Design fo a Portable Nuclear Magnetic Resonance Flow Meter

In this paper, a Halbach array-based Nuclear Magnetic Resonance (NMR) device for multiphase flow measurement is suggested. The design approach used simultaneously a three dimensional (3D) Finite-Element-Method (FEM)-based software combined with Particle Swarm Optimization (PSO) algorithm. The goal of the design is to generate a relatively intense and highly homogenous magnetic field inside the target sensing area using a compact and light weight magnets array. Simulation results on a device consisting of 12 Halbach arrays, each consisting of twelve (12) cuboid permanent magnet elements of size 20 mm × 20 mm × 46.5 mm size indicate that a highly homogenous magnetic field distribution of 0.890 Tesla maximal intensity and 606 ppm homogeneity could be achieved within a probe cross section of 40 mm diameter when the Halbach arrays are distant from each other by a distance of 4 mm. This is adequate for the desired application while it leads to a light and compact overall Halbach array of 21.6 kg weight and 600 mm length.