FLUID FLOW MONITORING

Abstract: Aerodynamic or hydrodynamic testing of shapes is performed by NMR (Nuclear Magnetic Resonance) image reconstruction. A fluid which is NMR opaque or translucent is passed through a duct in which non-magnetic shapes are mounted, and the duct is positioned within the working volume of an NMR imaging system.

Description: - 1 - Fluid Flow Monitoring This invention relates to methods and apparatus for monitoring the flow of fluids over shapes to determine the aerodynamic or hydrodynamic characteristics of the shapes, to reproduce the conventional function of wind tunnels. The method of the present invention is character¬ ized in that the shapes, which are mounted in a duct, are subjected to the flow of a fluid which comprises Nuclear Magnetic Resonance (N.M.R.) opaque or translucent material whose flow pattern is observed by NMR image reconstruction, the shapes being of non-magnetic material which is also NMR opaque or translucent. The shapes may be solid or hollow, representing ducts, trunking, vehicle bodies, aircraft or any other items con- ventionally tested in wind tunnels. If liquid flows are to be examined, water is passed through the duct, over and/or through the shape and conventional phase mapping techniques may be employed for image reconstruction. For gas flows, the fluid may comprise atomised water, steam or hydrated microspheras of hydron in air. Standard NMR phase mapping.or echo rephasing tech¬ niques may be employed to monitor steady flow characteristics, and for unstable flow conditions, various forms of rapid imaging techniques may be employed. 4243 - 2 - The invention also includes apparatus suitable for performing the above method, the apparatus being characterized in that the duct is defined within the working volume of an NMR imaging system and that apparatus for NMR image reconstruction is provided to permit observation of the flow pattern of fluid past the shapes. Two test arrangements are illustrated diagrammat- ically in Figs. 1 and 2, each of which represents an axial section through the NMR coils. A stream F of NMR opaque or translucent fluid is passed through the duct formed within the magnetic coil 1 and R.F. transmitting and gradient coils 2. In Fig. 1 the shape 3 to be tested is shown as a model of a motor car. Close coupled receiver coils 4 are located where they will not interfere with the fluid flow, being partly embedded in shape 3 and within the loop of a plastics belt 6, forming a "rolling 1* ; road. Fig. 2 merely shows a shape representing a flow duct, with the receiver coils 4 embedded in the shape.

Claims: CLAIMS: 1. A method of monitoring the flow of fluids over shapes to determine the aerodynamic or hydrodynamic characteristics of the shapes, wherein the shapes are mounted in a duct and subjected to a flow of fluid, characterized in that the fluid comprises NMR opaque or translucent material whose flow pattern is observed by NMR image reconstruction, the shapes being of non-magnetic material which is also NMR opaque or translucent. 2. A method according to claim 1, wherein the said fluid consists of: water; atomised water; steam; or hydrated microspheres of hydron in air. 3. Apparatus for monitoring the flow of fluids over shapes to determine the aerodynamic or hydrodynamic characteristics of the shapes, comprising a duct within which the shapes can be mounted and through which a fluid can be passed, characterized in that the duct (l) is defined within the working volume of an NMR imaging system, and that apparatus for NMR image reconstruction is provided to permit observation of the flow pattern of fluid past the shapes. 4- Apparatus according to claim 3, wherein close coupled receiver coils for NMR imaging are at least partly embedded in the shape or shapes to be tested.

Inventors: LONGMORE DONALD BERNARD, LONGMORE, DONALD, BERNARD
Applicants: LONGMORE DONALD BERNARD, LONGMORE, DONALD, BERNARD
Application year: 1987
Main classification: G01M9
IPC codes: G01M9, G01M10, G01P13