VM168

VM168
Magnetic Field in a Nonferrous Solenoid

Overview

Reference: W. B. Boast, Principles of Electric and Magnetic Fields, Harper & Brothers, New York, NY, 1948, pg. 243.
Analysis Type(s): Static Magnetic Field Analysis (ANTYPE = 0)
Element Type(s):
3D Coupled-Field Solid Elements (SOLID5)
Current Source Elements (SOURC36)
Input Listing: vm168.dat

Test Case

A nonferrous solenoid is wound with one layer of No. 26 enameled wire and carries a current I. Determine the magnetic flux density on the centerline at

  • the center of the coil

  • the end of the coil

  • at a point 5 inches from the end of the coil

Figure 240: Magnetic Field Problem Sketch

Magnetic Field Problem Sketch

Geometric PropertiesLoading
= 7.5 in
s = 5 in
r = 0.5 in
h = 6 in
d = 0.216
I = 0.5 A

Analysis Assumptions and Modeling Notes

The number of turns is N = s/d = 5/.0216 = 231. Therefore, N x I = 115.5 Ampere-turns. Since no ferromagnetic materials are present, the field due to induced magnetization, Hm = 0, and thus no scalar potential is required. The total field can be determined from the numerical integration of the coil source field upon specification of the coil with the current source element (SOURC36). Since the field is symmetric, an arbitrary arc of 10° is chosen with an additional symmetry plane taken along the coil midspan. A sufficient number of integration points (50) are chosen along the Z-axis to adequately represent the coil. Only one point is specified through the coil thickness. The Reduced Scalar Potential (RSP) is selected since only a source field is to be calculated.

Results Comparison

TargetMechanical APDLRatio
Bz (x 106)T at z = 011201120.651.001
Bz (x 106)T at z = 7.5 in (.1905 m)2.122.121.002

Figure 241: Axial Magnetic Field through Solenoid

Axial Magnetic Field through Solenoid