Stretchable Electrode Breakthrough: Archimedean Spiral Coil Lithium Anode

In this paper, a new method to calculate the self-inductance of the Archimedean spiral coil is presented. The proposed method is derived by solving Neumann’s integral formula, and the numerical tool is used to calculate the inductance value. The calculation results are verified with several conventional formulas derived from the Wheeler formula or its modified form and 3D finite element analyses. The comparison with simulation results shows that the conventional formula has an error of above 40% compared to the proposed method, which has below 7% when the wire diameter is reduced. To further check the validity, different sizes of the spiral coil are fabricated by changing the geometrical parameters such as the number of turns, turn spacing, inner radius, outer radius, and wire diameter. Litz wire is chosen for making the spiral coil, and bobbins are made using a 3D printer. Finally, the calculation results are compared with the experimental result. The error between them is less than 2%. The comparison with the conventional formulas, simulation, and measurement results shows the accuracy of the proposed method. This method can be used to calculate the self-inductance of wireless power coils, inductors and antenna design.

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EXPERIMENTAL INVESTIGATION OF THE CONVECTIVE HEAT TRANSFER IN A SPIRALLY COILED CORRUGATED TUBE WITH RADIANT HEATING

Facta Universitatis Series Mechanical Engineering ◽

10.22190/fume171001027d ◽

2017 ◽

Vol 15 (3) ◽

pp. 495 ◽

Cited By ~ 1

Author(s):

Milan Đorđević ◽

Velimir Stefanović ◽

Mića Vukić ◽

Marko Mančić

Keyword(s):

Heat Transfer ◽

Radiation Field ◽

Design Solution ◽

Laboratory Model ◽

Fluid Temperature ◽

Radiant Heating ◽

Archimedean Spiral ◽

Spiral Coil ◽

Corrugated Tube ◽

Heat Absorber

The Archimedean spiral coil made of a transversely corrugated tube was exposed to radiant heating in order to represent a heat absorber of the parabolic dish solar concentrator. The main advantage of the considered innovative design solution is a coupling effect of the two passive methods for heat transfer enhancement - coiling of the flow channel and changes in surface roughness. The curvature ratio of the spiral coil varies from 0.029 to 0.234, while water and a mixture of propylene glycol and water are used as heat transfer fluids. The unique focus of this study is on specific boundary conditions since the heat flux upon the tube external surfaces varies not only in the circumferential direction, but in the axial direction as well. Instrumentation of the laboratory model of the heat absorber mounted in the radiation field includes measurement of inlet fluid flow rate, pressure drop, inlet and outlet fluid temperature and 35 type K thermocouples welded to the coil surface. A thermal analysis of the experimentally obtained data implies taking into consideration the externally applied radiation field, convective and radiative heat losses, conduction through the tube wall and convection to the internal fluid. The experimental results have shown significant enhancement of the heat transfer rate compared to spirally coiled smooth tubes, up to 240% in the turbulent flow regime.

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Biomedical magnetic induction tomography using two-arm Archimedean spiral coil: A feasibility study

13th IEEE International Conference on BioInformatics and BioEngineering ◽

10.1109/bibe.2013.6701642 ◽

2013 ◽

Author(s):

Ziyi Zhang ◽

Peiguo Liu ◽

Dongming Zhou ◽

Hengdong Lei

Keyword(s):

Feasibility Study ◽

Magnetic Induction ◽

Archimedean Spiral ◽

Spiral Coil ◽

Magnetic Induction Tomography

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Numerical investigation on the convective heat transfer in a spiral coil with radiant heating

Thermal Science ◽

10.2298/tsci16s5215d ◽

2016 ◽

Vol 20 (suppl. 5) ◽

pp. 1215-1226

Author(s):

Milan Djordjevic ◽

Velimir Stefanovic ◽

Mica Vukic ◽

Marko Mancic

Keyword(s):

Heat Transfer ◽

Axial Direction ◽

Outer Wall ◽

Secondary Flows ◽

Temperature Fields ◽

Heat Transfer Fluid ◽

Radiant Heating ◽

Mean Flow ◽

Archimedean Spiral ◽

Spiral Coil

The objective of this study was to numerically investigate the heat transfer in spiral coil tube in the laminar, transitional, and turbulent flow regimes. The Archimedean spiral coil was exposed to radiant heating and should represent heat absorber of parabolic dish solar concentrator. Specific boundary conditions represent the uniqueness of this study, since the heat flux upon the tube external surfaces varies not only in the circumferential direction, but also in the axial direction. The curvature ratio of spiral coil varies from 0.029 at the flow inlet to 0.234 at the flow outlet, while the heat transfer fluid is water. The 3-D steady-state transport equations were solved using the Reynolds stress turbulence model. Results showed that secondary flows strongly affect the flow and that the heat transfer is strongly asymmetric, with higher values near the outer wall of spiral. Although overall turbulence levels were lower than in a straight pipe, heat transfer rates were larger due to the curvature-induced modifications of the mean flow and temperature fields.

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