The thermal conductivity of Kapton HN between 0.5 and 5 K

Lawrence, J L; Patel, A. B.; Brisson, J. G.

doi:10.1016/s0011-2275(00)00028-x

Cited by 27 publications

(14 citation statements)

References 8 publications

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“…2. Data from Baudouy [16] in the superfluid region agree with those from Lawrence et al [17] that are taken over a larger temperature range. Furthermore data from Lawrence et al and from NIST [18], which refer to two different temperature ranges, are in agreement in the overlap of the two ranges.…”

Section: Model Descriptionsupporting

confidence: 82%

Heat transfer through cable insulation of Nb–Ti superconducting magnets operating in He II

Granieri¹

2013

Cryogenics

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a b s t r a c tThe operation of Nb-Ti superconducting magnets in He II relies on superfluidity to overcome the severe thermal barrier represented by the cable electrical insulation. In wrapped cable insulations, like those used for the main magnets of the Large Hadron Collider (LHC) particle accelerator, the micro-channels network created by the insulation wrappings allows to efficiently transfer the heat deposited or generated in the cable to the He bath.In this paper, available experimental data of heat transfer through polyimide electrical insulation schemes are analyzed. A steady-state thermal model is developed to describe the insulation of the LHC main dipole magnets and the Enhanced Insulation proposed for the High Luminosity LHC upgrade (HL-LHC), according to the relevant geometric parameters. The model is based on the coupled mechanisms of heat transfer through the bulk of the dielectric insulation and through micro-channels between the insulation tapes.A good agreement is found between calculations and tests performed at different applied pressures and heating configurations. The model allows identifying the heat fluxes in the cable cross-section as well as the dimensions of the micro-channels. These dimensions are confirmed by microscope images of the two insulations schemes.

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Section: Model Descriptionsupporting

confidence: 82%

Heat transfer through cable insulation of Nb–Ti superconducting magnets operating in He II

Granieri¹

2013

Cryogenics

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“…Conductivity of polyimide (Kapton) has been measured by Lawrence [12], boundary resistance at the Cu-He II interface is taken from [13] and at the polyimide-He II interface from [14].…”

Section: Heat Transfer Modelmentioning

confidence: 99%

Cable Insulation Scheme to Improve Heat Transfer to Superfluid Helium in Nb-Ti Accelerator Magnets

China

Tommasini

2008

IEEE Trans. Appl. Supercond.

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Abstract-In superconducting magnets operating at high heat loads as the ones for interaction region of particle colliders or for fast cycling synchrotrons, the limited heat transfer capability of state-of-the-art electrical insulation may constitute a heavy limitation to performance. In the LHC main magnets, Nb-Ti epoxy-free insulation, composed of polyimide tapes, has proved to be permeable to superfluid helium, however the heat flux is rather limited.After a review of the standard insulation scheme for Nb-Ti and of the associated heat transfer mechanisms, we show the existence of a large margin available to improve insulation permeability. We propose a possible way to profit of such a margin in order to increase significantly the maximum heat flux drainable from an all polyimide insulated Nb-Ti coil, as it is used in modern accelerator magnets.

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“…This gives us an interconnection of the ith system with the neighboring systems, as illustrated in Figure 4 The following simulation in Matlab shows the behavior of a simple piezoelectric beam. We consider Kapton [8] as material for the base layer, and polyvinylidene flouride (PVDF) [15] as piezoelectric material. The base layer has a length of 1 m, while the thickness and the width of the beam are 2 cm.…”

Section: Interconnection Of the Subsystems And Simulation Resultsmentioning

confidence: 99%

“…For the second simulation we apply a voltage of 0.1 · t V until we reach a voltage of 0.5 V ; see Additionally we present some simulation results of a shape controlled beam. Therefore we consider a beam made of Kapton [8] with a length of 1 m, a height of 25 · 10 −4 m, and a width of 50 · 10 −4 m which is always clamped at the right sides. The clamping on the left side depends then on the shape we would like to achieve.…”

Section: Interconnection Of the Subsystems And Simulation Resultsmentioning

confidence: 99%

Structure Preserving Spatial Discretization of a 1-D Piezoelectric Timoshenko Beam

Voß¹,

Scherpen²

2011

Multiscale Model. Simul.

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In this paper we show how to spatially discretize a distributed model of a piezoelectric beam representing the dynamics of an inflatable space reflector in port-Hamiltonian (pH) form. This model can then be used to design a controller for the shape of the inflatable structure. Inflatable structures have very nice properties, suitable for aerospace applications, e.g., inflatable space reflectors. With this technology we can build inflatable reflectors which are about 100 times bigger than solid ones. But to be useful for telescopes we have to achieve the desired surface accuracy by actively controlling the surface of the inflatable. The starting point of the control design is modeling for control. In this paper we choose lumped pH modeling since these models offer a clear structure for control design. To be able to design a finite dimensional controller for the infinite dimensional system we need a finite dimensional approximation of the infinite dimensional system which inherits all the structural properties of the infinite dimensional system, e.g., passivity. To achieve this goal first divide the one-dimensional (1-D) Timoshenko beam with piezoelectric actuation into several finite elements. Next we discretize the dynamics of the beam on the finite element in a structure preserving way. These finite elements are then interconnected in a physical motivated way. The interconnected system is then a finite dimensional approximation of the beam dynamics in the pH framework. Hence, it has inherited all the physical properties of the infinite dimensional system. To show the validity of the finite dimensional system we will present simulation results. In future work we will also focus on two-dimensional (2-D) models.

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The thermal conductivity of Kapton HN between 0.5 and 5 K

Cited by 27 publications

References 8 publications

Heat transfer through cable insulation of Nb–Ti superconducting magnets operating in He II

Heat transfer through cable insulation of Nb–Ti superconducting magnets operating in He II

Cable Insulation Scheme to Improve Heat Transfer to Superfluid Helium in Nb-Ti Accelerator Magnets

Structure Preserving Spatial Discretization of a 1-D Piezoelectric Timoshenko Beam

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