Generation and confinement of uniform magnetic fields with distributions of surface currents
This paper presents the methodology for generation and confinement of a uniform magnetic field of intensity H/sub 0/ in an arbitrary assigned polyhedral cavity C enclosed by planar surfaces s/sub h/. The design methodology presented in this paper can generate novel self-shielding polyhedral structures of surface currents. Unlike in conventional solenoid magnet, the field generated by these structures is perpendicular to the main axis of the cavity.
Equivalent structures of permanent magnets and electric currents designed to generate uniform fields
Generation and confinement of a magnetic field by means of permanent magnets as well as time‐independent electric currents are analyzed, and the conditions of existence of uniform field solutions are established in the general case of structures that enclose a region of arbitrary geometry. Basic properties of distributions of the electric currents are compared with the properties of yokeless structures of permanent magnets intended to generate the same uniform field within the same region.
A comparison of experimental thermal stratification parameters for an oil/pebble-bed thermal energy storage (TES) system during charging
Six different experimental thermal stratification evaluation parameters during charging for an oil/pebble-bed TES system are presented. The six parameters are the temperature distribution along the height of the storage tank at different time intervals, the charging energy efficiency, the charging exergy efficiency, the stratification number, the Reynolds number and the Richardson number. These parameters are evaluated under six different experimental charging conditions. Temperature distribution along the height of the storage tank at different time intervals and the stratification number are parameters found to describe thermal stratification quantitatively adequately. On the other-hand, the charging exergy efficiency and the Reynolds number give important information about describing thermal stratification qualitatively and should be used with care. The charging energy efficiency and the Richardson number have no clear relationship with thermal stratification.