Thermal contact conductance of molybdenum-sulphide-coated joints at low temperature
01 Oct 2007-Journal of Thermophysics and Heat Transfer (American Institute of Aeronautics and Astronautics (AIAA))-Vol. 21, Iss: 4, pp 811-813
TL;DR: In this paper, the effectiveness of MoS2 coating on aluminum and stainless steel contacts at different interface temperatures and loads is determined, and experiments are carried out over a range of low temperatures.
Abstract: J OINTS used for cryogenic structural supports and satellite deployment mechanisms are often exposed to very low temperatures. These joints, unlike those for ground applications, do not usemetal-to-metal contact. A conducting or insulating interstitial medium is introduced at the interface for controlling the contact conductance. When gold and silver plating and the use of thermal grease is adopted for enhancing the contact conductance, a reduction in contact conductance is achieved by providing a nonmetallic coating at the interfaces. Molybdenum sulphide (MoS2) is widely used as the nonmetallic coating in cryogenic structural joints, because it not only reduces the joint conductance but also provides dry lubrication at the joint. A precise knowledge of the contact conductance of the coated joint is essential, especially at the low temperatures at which it is used for estimating the parasitic heat-conduction loads through the cryogenic structural supports. A variety of nonmetallic coatings such as manganese dioxide, silicon elastomer, carbon black, and polyethylene have been evaluated over a range of interface temperatures and pressures [1,2]. The temperatures considered in the preceding studies are essentially above the ambient. A general model for computing the conductance in multilayered contacts was developed by Muzychka et al. [3] for a flux tube having two applied coatings. The need remains to determine contact conductance of nonmetallic coating [4] such as MoS2 at low temperatures. In this paper, the effectiveness of MoS2 coating on aluminumand stainless steel contacts at different interface temperatures and loads is determined. Experiments are carried out over a range of low temperatures.
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TL;DR: Theoretical prediction of thermal contact resistance is reviewed in this paper, where the authors provide a perspective on further promising research, which would be beneficial to understand mechanisms and engineering applications of the thermal contact resistances in heat transport phenomena.
Abstract: Theoretical prediction research on thermal contact resistance is reviewed in this paper. In general, modeling or simulating the thermal contact resistance involves several aspects, including the descriptions of surface topography, the analysis of micro mechanical deformation, and the thermal models. Some key problems are proposed for accurately predicting the thermal resistance of two solid contact surfaces. We provide a perspective on further promising research, which would be beneficial to understanding mechanisms and engineering applications of the thermal contact resistance in heat transport phenomena.
38 citations
TL;DR: In this article, a thermal design procedure for micro-and nanosatellites that can be completed in one year is proposed, where two thermal design concepts keep components within their design temperature range, reducing the temperature change by using the whole structure for heat storage and reducing the change of the inner structure where the most temperature sensitive components are mounted.
Abstract: This paper proposes a thermal design procedure for micro- and nanosatellites that can be completed in one year. Two thermal design concepts keep components within their design temperature range, reducing the temperature change by using the whole structure for heat storage and reducing the temperature change of the inner structure where the most temperature-sensitive components are mounted. One- and two-nodal analysis methods are used for the former and latter concepts, respectively, to clarify the combinations of optical properties for the structures and components to keep within the design temperature range of the components. Finally, multinodal analysis is performed for detail design based on the optical properties clarified from the one- and two-nodal analyses. This thermal design procedure was applied to the Hodoyoshi-1 satellite, which is a cube about 50 cm on a side, has two inner plates and has solar cells on the body, is on a sun-synchronous orbit at an altitude of about 500 km, and is pointing to...
12 citations
TL;DR: In this article, thermal contact conductance across joints at cryogenic temperature in presence of interstitials like silicon based conductive compound, epoxy based adhesive layer and acrylate based anaerobic sealant are explored.
6 citations
01 Jan 2014
TL;DR: In this article, the authors introduce foils, powders, wire screens and epoxies to control the TCC of a solid-to-solid contact area, which is only a small fraction of the apparent area.
Abstract: As noted in Chapter 1, the actual solid-to-solid contact area, in most mechanical joints, is only a small fraction of the apparent area. The voids between the actual contact spots are usually occupied by some conducting substance such as air. Other interstitial materials may be deliberately introduced to control, that is, either to enhance or to lessen, the TCC: examples include foils, powders, wire screens and epoxies. To enhance the conductance the bare metal surfaces may also be coated with metals of higher thermal conductivity by electroplating or vacuum deposition. Greases and other lubricants also provide alternative means of enhancing the TCC.
3 citations
01 Feb 2018
TL;DR: In this paper, boundary element method (BEM) and conjugate gradient method are combined to estimate the TCR in planar mediums, and the positions of temperature measuring points can be selected randomly because of the characteristic of BEM.
Abstract: Thermal contact resistance(TCR) is one of the important parameters in heat transfer problems of engineering, and it is necessary to estimate the value of TCR effectively in many engineering fields. Considering the limitation of current estimation methods of TCR such as only focusing on one-dimensional thermal conduction, getting a single value of TCR merely, and the temperature measuring points only being placed in temperature gradient direction of mediums, boundary element method(BEM) and conjugate gradient method are combined to estimate the TCR in planar mediums. The value of TCR in relation to the position of contact interface line is estimated with this method, and the positions of temperature measuring points can be selected randomly because of the characteristic of BEM that there is no necessity to discrete the inner area and it is sufficient to discrete the boundary. The analysis of calculation examples base on heat transfer model of planar medium demonstrates that:this method can estimate the TCR effectively, but the ill-posedness is also existed in this method which is one of the inverse problems, and the calculation error of TCR is increased with the distance from temperature measuring points to contact interface, the estimation precision and stability can be improved after optimization with least square method.
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TL;DR: In this article, a solution for computing the thermal spreading resistance of a planar circular contact on a doubly-coated substrate is presented, and a model is developed to compute the contact conductance between a bare substrate and a coated substrate.
Abstract: Application of highly conductive coatings to contacting surfaces is a commonly employed method to enhance thermal contact conductance. In many applications it is often necessary to apply an intermediate coating such that the conductive coating may be applied to a nonadhering substrate. In these instances, it is desirable to predict the effect that the intermediate and final coatings have on the spreading resistance. A solution for computing the thermal spreading resistance of a planar circular contact on a doubly coated substrate is presented. Also, a model is developed to compute the contact conductance between a bare substrate and a coated substrate. Comparisons are made with data obtained in the literature for which no analytical model was available. Solution of the governing equations and numerical computation of the spreading resistance were obtained using computer algebra systems
24 citations
TL;DR: In this paper, the authors derived a universal relationship between overall support conductance, the Δ T involved, and the supported mass by examining a variety of flight-proven designs for cryogenic structural supports and then normalizing the data given the known relationships between material conductivity and temperature.
12 citations
"Thermal contact conductance of moly..." refers background in this paper
...The need remains to determine contact conductance of nonmetallic coating [4] such as MoS2 at low temperatures....
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