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Motor Frame Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Though a wide variety of threaded fasteners are used in engineering practice, two types of thread fasteners primarily used in motor assemblies and installations are as follows: Bolt-nut fasteners, in which a bolt passes through slightly larger holes in two joint members and is engaged with a hexagonal nut. The desired tightness of the fastener can be achieved by applying a wrench to either the bolt head or nut. In this way, the two joint members are clamped between bolt head and nut, as shown in Figure 5.38. The grip length lg is the sum of the thicknesses of both joint members: lg=l1+l2Screw-threaded member fasteners, in which the threads of the screw are threaded into an internally threaded hole of the lower joint member, as shown in Figure 5.39. The effective grip length is determined according to the bolt diameter relative to the thickness of the first joint member: lg={l1+l2/2forl2<dl1+d/2forl2≥d
Chromium Carbide Coatings for Inner-Side Fuel Cladding Protection: A Reactor Physics–Based Performance Analysis
Published in Nuclear Science and Engineering, 2023
Rofida H. Khlifa, Nicolay N. Nikitenkov, Viktor N. Kudiiarov
The calculation model is based on the VVER-1200 fuel assembly. It is characterized by its hexagonal geometry that contains 331 hexagonal unit cells. These unit cells include 312 fuel pins, one central tube, and 18 guide channels. A central hole is incorporated into the fuel pellets to reduce pellet stresses and provide additional space for gaseous fission products. The fuel rods are 373 cm long, and the rod pitch is 1.275 cm. Fuel pullets have an outer radius of 0.380 cm with UO2 enriched to 4.5% used as fuel material. The Zr-based alloy E110 (Zr-1%Nb) is used as cladding material, and E-635 used for both the central and the guide channels. The chemical composition of CrC coatings used in this study is Cr7C3. All elements in the material composition were considered to be present at their natural isotopic abundance.
A Stylized 3-D Benchmark Problem Set Based on the Pin-Fueled SmAHTR
Published in Nuclear Technology, 2020
K. Lisa Reed, Farzad Rahnema, Dingkang Zhang, Dan Ilas
In the original solid cylindrical fuel option, prismatic hexagonal graphite blocks with a 22.5-cm apothem as the outer boundary and a 16.94-cm radius opening for the cylindrical coolant channel are detailed. Each assembly has six concentric rings of pins arranged in a hexagonal lattice pattern with a pitch of 3.08 cm. The center pin and middle ring, which account for a total of 19 pins, are solely graphite pins, and the TRISO compacts make up the other 72 (fuel) pins. Each fuel pin is 1.1 cm in radius with the TRISO packed in graphite at a 50% volumetric packing fraction. The fuel pins are cladded in 0.3 cm of graphite to yield an outer radius of 1.4 cm, and the graphite pins are solely 1.4-cm-radius graphite cylindrical pins. The assembly in the original preconceptual design from the ORNL report1 is shown in Fig. 3. Within the assembly, spacers for the cylindrical pin fuel type are not specified, nor are any other support structures to suspend the pins.
The effect of aperture shape, angle of incidence and polarization on shielding effectiveness of metallic enclosures
Published in Journal of Microwave Power and Electromagnetic Energy, 2019
Ibrahim Bahadir Basyigit, Habib Dogan, Selcuk Helhel
In this section; aluminium enclosures with rectangular, square, circular, hexagonal and equilateral triangle type apertures have been selected. Each aperture area has been fixed at 5625 mm2; therefore the height of each aperture varies. As seen in Figure 4, 67.54 dB ESE performance has been obtained as the highest value for rectangular aperture and 24.46 dB lowest performance for equilateral triangle aperture. One may explain these results by means of Figure 5: When the polarization angle α is 90° (the angle between electric field and normal of aperture), electric field coupling into the enclosure will be more as expected. ESE performance gets lower with increased electric field amplitude Amnp (Balanis 2012), as described in Equations (2a)–(2d).