Thermal contact conductance of elastomeric gaskets

Mirmira, S.; Marotta, Egidio; Fletcher, L. S.

doi:10.2514/6.1997-139

Cited by 5 publications

(8 citation statements)

References 2 publications

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“…In general, contact resistance was shown to be a strong function of temperature due to the large temperature dependence of the rubber thermal conductivity and to a lesser extent of pressure P due to the elastomer softness. An experimental study conducted by Mirmira et al [8] showed that thermal contact conductance of some commercial elastomeric gaskets and graphitebased materials become less dependent on the contact pressure as the load increased, with the bulk conductance becoming predominant in the high pressure range (around 1000 kP a − 1500 kP a). The authors observed that the change in the mean interface temperature did not significantly effect the thermal conductance values for the gasket materials.…”

Section: Review Of Previous Workmentioning

confidence: 99%

“…Copyright © 2003 by ASME [3] Al 2024-T4 Silicone elastomers, Fluocarbon elastomer, Nitrile elastomer Fletcher et al [4] Al 2024-T4 Ethylene vinyl acetate copolymers, Ethyl vinyl acetate copolymer, Polyethylene homopolymer Ochterbeck et al [5] Al 6061-T6 Polyamide in combinations with foil, paraffin, diamonds, copper Marotta and Fletcher [6] Al 6061-T6 Polyethylene, PVC, Polypropylene, Teflon, Delrin, Nylon, Polycarbonate, Phenolic Parihar and Wright [7] SS 304 Silicone rubber (elastomer) Mirmira et al [8] Al 6061-T6 Elastomeric gaskets (Cho-Therm, T-pli, Grafoil) Fuller and Marotta [9] Al 6061, SS Delrin, Teflon, Polycarbonate, PVC Marotta et al [12] Al 6061 eGraf, Furon (graphite-based) mer thickness at zero load. Therefore, the joint conductance was defined as:…”

Section: Review Of Previous Workmentioning

confidence: 99%

See 1 more Smart Citation

Effective Thermophysical Properties of Thermal Interface Materials: Part I — Definitions and Models

Savija

Culham

Yovanovich

2003

2003 International Electronic Packaging Technical Conference and Exhibition, Volume 2

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The conductivity of thermal interface materials are typically determined using procedures detailed in ASTM D 5470. The disadvantages of using these existing procedures for compliant materials are discussed along with a proposed new procedure for determining thermal conductivity and Young’s modulus. The new procedure, denoted as the Bulk Resistance Method, is based on experimentally determined thermal resistance data and an analytical model for thermal resistance in joints incorporating thermal interface materials. Two versions of the model are presented, the Simple Bulk Resistance Model, based on the interface material thickness prior to loading and a more precise version denoted as the General Bulk Resistance Model, that includes additional parameters such as surface characteristics and thermophysical properties of the contacting solids. Both methods can be used to predict material in situ thickness as a function of load.

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Section: Review Of Previous Workmentioning

confidence: 99%

Section: Review Of Previous Workmentioning

confidence: 99%

Effective Thermophysical Properties of Thermal Interface Materials: Part I — Definitions and Models

Savija

Culham

Yovanovich

2003

2003 International Electronic Packaging Technical Conference and Exhibition, Volume 2

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“…An experimental investigation by Mirmira et al 6 revealed that the thermal joint conductance of several commercially available elastomeric materials became less dependent on apparent interface pressure. These values occurred as the interface loading increased significantly, with the bulk conductance becoming predominant at the high-pressure range (1-500 kPa).…”

Section: Literature Reviewmentioning

confidence: 99%

Thermal Joint Conductance of Low-Density Polyethylene and Polyester Polymetric Films: Experimental

Kim

Marotta

Fletcher

2006

Journal of Thermophysics and Heat Transfer

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The flow of thermal energy across a joint where one or more surfaces come into contact is an important engineering consideration. Studies of metal/metal contacts at an interface have been investigated extensively and are well documented in the literature. Although equally important in many engineering application, the study of nonmetallic or organic contacting surfaces is still in its infancy. Currently, an elastic model exists for predicting the thermal performance of metal/polymer joints. In addition, a plastic model was recently proposed to account for plastic deformation of the contacting asperities. Both thermal contact models have been compared to experimental polymer layers that are relatively thick. The present objective was to investigate experimentally two commercially important polymeric film types for thermal conductance ranging from 254 to 12.2 μm in thickness under interface pressures varied from 103.4 (15) to 23,774.5 kPa (3450 psi). In each of the experimental tests, the ambient fluid at the contacting interface was air. One other objective was to conduct film nanoindentation measurements to possibly deduce a microdeformation mode. Surface metrology and film morphology are presented with a goal to incorporate these results into future modeling endeavors. The polymeric films investigated were low-density polyethylene and polyester, for example, Mylar ® . NomenclatureA a = apparent contact area, m 2 A t = true contact area at maximum load/penetration, m 2 d = distance between atoms, m E = Young's modulus, GPa F = applied force, N f g = combination of terms, dimensionless H = microhardness, GPa h b = bulk conductance, W/m 2 · K h c = contact penetration depth, nm h contact = contact conductance, W/m 2 · K h j = joint conductance, W/m 2 · K I g = gap conductance integral, dimensionless k = material conductivity, W/m 2 · K L = applied force, μN M = gas rarefaction parameter, m m = combined absolute asperity slope, rad n = plane index number P = apparent contact pressure, GPȧ Q = joint heat transfer rate, W R b = bulk resistance R c = contact resistance, K/W R g = gap resistance, K/W R j = joint resistance, K/W S = contact stiffness, d p/dh c T = temperature, K t = final thickness, m t 0 = original thickness, m Y = mean plane separation, m α = tip constant, 1.168 for Berkovich tip Presented as Paper 2005-760 at the AIAA Aerospace Sciences γ = plasticity index T j = joint temperature drop, K = see Eq. (24) θ = scattering angle, deg λ = incident wavelength, m ν = Poisson's ratio σ = effective surface roughness, √ (σ 2 1 + σ 2 2 ), m) ω = uncertainty parameter Subscripts c = contact e = elastic g = gap i = index number, interface p = polymer r = reduced s = harmonic 1, 2 = surface of solids 1 and 2

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“…Mirmira et al 18 conducted an experimental investigationmeasuring the thermal contactconductanceof a wide range of commercially available elastomeric gaskets. The experimental investigation was conducted with the elastomeric gaskets maintained at mean interface temperaturesof 20 and 80 ± C and over a mean interfacepressure range of 172-6900 kPa (25-1000 psi).…”

Section: Metal/polymer Thermal Contact Conductance Datamentioning

confidence: 99%

Thermal Contact Conductance of Metal/Polymer Joints: An Analytical and Experimental Investigation

Fuller

Marotta

2001

Journal of Thermophysics and Heat Transfer

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The heat ow across a metal/polymer interface is a very important problem in many modern engineering applications. A thermal joint conductance model that employs the surface mechanics of a contact interface in conjunction with an existing elastic thermal contact conductance model was developed. In developing the model, an elastic contact hardness term was derived to predict the actual contact area of a metal/polymer interface under loading. The model predicts a microscopic resistance region where the interface resistance is dominant and a bulk resistance region where the thermal conductivity of the polymer is dominant. An experimental apparatus was fabricated, and a successful experimental program was conducted. New experimental data were gathered on different polymeric specimens over a pressure range of 138-2758 kPa (20-400 psi). The experimental data were compared to the proposed thermal joint conductance model. It was found that the proposed model predicted the data quite well. The data followed the predicted trends for both the microscopic and bulk resistance regions. Nomenclature A a= apparent area of contact, m 2 A r = real area of contact, m 2 a c = contact radius, m a 0 = Hertzian contact radius, m c = half-width of plane contact area, melastic modulus of polymer, Pa E s = elastic modulus of substrate, Pa H c = contact microhardness, Pa H e = Mikic elastic hardness (E 0 = p 2)£ m, Pa H ep = polymer elastic hardness, Pa h bulk = thermal bulk conductance, W/m 2 K h c = thermal contact conductance, W/m 2 K h e = dimensionless elastic conductance h j = thermal joint conductance, W/m 2 K h j exp = experimentally calculated joint conductance, W/m 2 K h micro = thermal microscopic conductance, W/m 2 K J .t / = creep compliance k ux = thermal conductivity of ux meter, W/m K k p = thermal conductivity of polymer, W/m K k s = harmonic mean thermal conductivity, W/m K L = load, N m ab = mean absolute asperity slope, rad n = number of contact spots per unit area of apparent contact, m ¡2 P = apparent pressure, Pa P=H c = dimensionless plastic contact pressure P=H e = dimensionless elastic contact pressure P m = mean pressure at interface, Pa Q = heat rate, W q = heat ux through ux meter, W/m 2 R b = bulk thermal resistance, K/W R g;1 = gap resistance at interface 1, K/W R g;2 = gap resistance at interface 2, K/W R j = joint resistance, K/W R micro = microscopic thermal resistance, K/W R t;c = contact resistance, K/W R 1 = thermal resistance for upper interface, K/W R 2 = thermal resistance for lower interface, K/W T c = temperature of specimen, K T sl = temperature of lower interface of specimen, K T su = temperature of upper interface of specimen, K T 1 = temperature at surface 1, K T 2 = temperature at surface 2, K t = elastic layer (polymer) thickness, m t f = polymer thickness after loading, m t 0 = polymer thickness before loading, m t ¤ = critical polymer thickness, m Y = separation distance between contacting surfaces, m Y .t / = relaxation modulus " p = strain on polymer in the vertical directioņ = dimensionle...

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Thermal contact conductance of elastomeric gaskets

Cited by 5 publications

References 2 publications

Effective Thermophysical Properties of Thermal Interface Materials: Part I — Definitions and Models

Effective Thermophysical Properties of Thermal Interface Materials: Part I — Definitions and Models

Thermal Joint Conductance of Low-Density Polyethylene and Polyester Polymetric Films: Experimental

Thermal Contact Conductance of Metal/Polymer Joints: An Analytical and Experimental Investigation

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