Heat transfer through cyanate ester epoxy mix and epoxy TGPAP - DETDA electrical insulations at superfluid helium temperature

Abstract

A high magnetic field accelerator magnet of 13 T is being developed in Work Package 7 of the European Union FP7 project EuCARD. The application is to enable higher luminosities and energies for accelerators such as the LHC. The high magnetic field demands superconductors that require a heat treatment step such as Nb 3 Sn. This paper reports thermal tests on conventional composite electrical insulation with pressurized superfluid helium at atmospheric pressure as a coolant. Two composite insulation systems composed of cyanate ester epoxy mix or a tri-functional epoxy (TGPAP-DETDA) with Sglass fiber, have been chosen as candidate materials. The knowledge of their thermal properties is necessary for the thermal design and therefore samples have been tested in pressurized He II where heat is applied perpendicularly to the fibers between 1.6 K and 2.0 K. Overall thermal resistance is determined as a function of temperature and the results are compared with other electrical insulation systems used for accelerator magnets.

Experimental investigation of heat transfer through porous media in superfluid helium

“…The usual electrical insulation of this type of magnet is made of fiberglass tape impregnated with epoxy resin. The superconducting coil cooling is mainly controlled by conductive heat transfer and Kapitza resistance [3][4][5][6]. To enhance the heat transfer, new type of insulations based on ceramic materials were developed [7].…”

Curing of a Bisphenol E Based Cyanate Ester Using Magnetic Nanoparticles as an Internal Heat Source through Induction Heating

“…As a group, cyanate esters tend to give materials with high glass transition temperatures ( T g ) and very low dielectric constants as well as other useful properties such as low moisture absorption, low volatility, reduced toxicity, resistance to fire, and many others . These properties make cyanate ester resins useful for a wide variety of fields such as applications in aerospace, , pressure-sensitive adhesives, magnet insulation, and electric insulators as well as flexible circuitry, surface finishes, photonics, and biomedical applications . Kessler et al have studied the properties of bisphenol E cyanate ester nanocomposites with embedded nanoparticles of alumina, − silica, , zirconium tungstate, , and recently microparticles of iron oxide coated with silica using standard polymerization techniques.…”

The EuCARD High Field Magnet Project

“…Presently a 2D model with HeII and a 3D model are under development. The outcome of the thermal modelling is used for the design of the FRESCA2 magnet [22], [24].…”