229 citations · 1.5k across the 32 of their papers we have counts for
15 papers · 1 filter
Metamaterial anisotropic flux concentrators and magnetic arrays
R. Bjørk, A. Smith, C. R. H. Bahl
A metamaterial magnetic flux concentrator is investigated in detail in combination with a Halbach cylinder of infinite length. A general analytical solution to the field is determi…
Determining the minimum mass and cost of a magnetic refrigerator
R. Bjørk, A. Smith, C. R. H. Bahl +1
An expression is determined for the mass of the magnet and magnetocaloric material needed for a magnetic refrigerator and these are determined using numerical modeling for both par…
The influence of the magnetic field on the performance of an active magnetic regenerator (AMR)
R. Bjørk, K. Engelbrecht
The influence of the time variation of the magnetic field, termed the magnetic field profile, on the performance of a magnetocaloric refrigeration device using the active magnetic…
Comparison of adjustable permanent magnetic field sources
R. Bjørk, C. R. H. Bahl, A. Smith +1
A permanent magnet assembly in which the flux density can be altered by a mechanical operation is often significantly smaller than comparable electromagnets and also requires no el…
Improving magnet designs with high and low field regions
R. Bjørk, C. R. H. Bahl, A. Smith +1
A general scheme for increasing the difference in magnetic flux density between a high and a low magnetic field region by removing unnecessary magnet material is presented. This is…
Magnetocaloric properties of LaFeCoSi and commercial grade Gd
R. Bjørk, C. R. H. Bahl, M. Katter
The magnetocaloric properties of three samples of LaFeCoSi have been measured and compared to measurements of commercial grade Gd. The samples have (x=0.86, y=1.…
An optimized magnet for magnetic refrigeration
R. Bjørk, C. R. H. Bahl, A. Smith +2
A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halb…
The ideal dimensions of a Halbach cylinder of finite length
R. Bjørk
In this paper the smallest or optimal dimensions of a Halbach cylinder of a finite length for a given sample volume and desired flux density are determined using numerical modeling…
The sintering behavior of close packed spheres
R. Bjørk, V. Tikare, H. L. Frandsen +1
The sintering behavior of close packed spheres is investigated using a numerical model. The investigated systems are the body centered cubic (BCC), face centered cubic (FCC) and he…
Review and comparison of magnet designs for magnetic refrigeration
R. Bjørk, C. R. H. Bahl, A. Smith +1
One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the e…
Analysis of the internal heat losses in a thermoelectric generator
R. Bjørk, D. V. Christensen, D. Eriksen +1
A 3D thermoelectric numerical model is used to investigate different internal heat loss mechanisms for a thermoelectric generator with bismuth telluride p- and n-legs. The model co…
Demagnetization factor for a powder of randomly packed spherical particles
R. Bjørk, C. R. H. Bahl
The demagnetization factors for randomly packed spherical particle powders with different porosities, sample aspect ratios and monodisperse, normal and log-normal particle size dis…
Optimization and improvement of Halbach cylinder design
R. Bjørk, C. R. H. Bahl, A. Smith +1
In this paper we describe the results of a parameter survey of a 16 segmented Halbach cylinder in three dimensions in which the parameters internal radius, $r_{\mathrm{\scriptsize{…
In situ characterization of delamination and crack growth of a CGO-LSM multi-layer ceramic sample investigated by X-ray tomographic microscopy
R. Bjørk, V. Esposito, E. M. Lauridsen +5
The densification, delamination and crack growth behavior in a CeGdO (CGO) and (LaSrMnO (LSM) multi-layer ceramic sample was…
Analysis of the magnetic field, force, and torque for two-dimensional Halbach cylinders
R. Bjørk, C. R. H. Bahl, A. Smith +1
The Halbach cylinder is a construction of permanent magnets used in applications such as nuclear magnetic resonance apparatus, accelerator magnets and magnetic cooling devices. In…