Thermochemical erosion and thermophysical properties of phenolic resin/carbon fiber/graphite nanocomposites

Sabagh, Samire; Ahmad, A.L.; Bahramian, Ahmad Reza

doi:10.1177/0731684416669600

Cited by 14 publications

(12 citation statements)

References 36 publications

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“…Bahramian et al used a finite difference method for solving 1‐dimensional ablation equation for the case where thermal properties of materials were temperature dependent. Solving the ablation equation using numerical techniques such as finite difference and finite element methods requires consideration of stability and convergence .…”

Section: Introductionmentioning

confidence: 99%

“…A kinetic decomposition model has been introduced by Lyon for charring polymeric composites and applied to calculate the thermal degradation kinetic parameters (such as activation energy and degree of thermal decomposition) of samples as be used by Bahramian et al for phenolic composite ablatives also. Isothermal mass loss equation has been driven by Lyon as follows:

\frac{m ((), t)}{m_{0}} = 1 - ([], \frac{k_{g}}{k_{g} + k_{c}}) ({}, 1 - exp ((), - k_{p} t)) .

…”

Section: Introductionmentioning

confidence: 99%

“…Equation shows that as t → ∞, the residual mass approaches to an equilibrium value at constant temperature given by the following equation

\frac{m_{\infty}}{m_{0}} = ([], \frac{k_{c}}{k_{g} + k_{c}}) \equiv y_{c} .

…”

Section: Introductionmentioning

confidence: 99%

“…Assuming Arrhenius forms for k g ( k g = A g exp (− E g / RT )) and k c ( k c = A c exp (− E c / RT )) in Equation , it can be rewritten as follows:

y_{c} = y_{c} ((), T) = {[1 + \frac{A_{g}}{A_{c}} exp [- (E_{g} - E_{c}) / RT]]}^{- 1} .

…”

Section: Introductionmentioning

confidence: 99%

“…Substituting Equation into Equation yields the final results for the mass loss in the rate constant for thermolysis of primary chemical bonds in the polymer, k :

\frac{m ((), t)}{m_{\circ}} = y_{c} + ((), 1 - y_{c}) exp ((), - italickt) .

…”

Section: Introductionmentioning

confidence: 99%

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Ablation behavior of organoclay‐NBR insulator: Modeling and experimental

2018

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Summary Nitrile‐based nanocomposite heat insulators are very attractive materials compared with their similar nonelastomeric counterparts, due to their higher deformation bearing capacity in special applications. Modeling of these ablative nanocomposites enables us to determine the exact required thickness of the insulator and temperature distribution across it at predetermined thermal conditions. The complete form of the ablation equation is a transient nonlinear second‐order differential equation with variable temperature‐dependent thermo‐physical properties, which must be determined during thermal degradation. In this work, in addition to experimental investigation of ablative elastomeric nanocomposites based on NBR, the ablation process is modeled analytically with perturbation theory in the Lagrangian coordinate system because of surface recession and moving boundaries. Kirchhoff transformation was used to get rid of the temperature dependence of k in each zonal of virgin and char. The theoretical results were confirmed by experimental data obtained from the oxyacetylene flame test. The results proposed a competitive nitrile‐based nanocomposite heat insulator with superior ablation properties: mass ablation rate 0.014 g s−1, linear ablation rate 0.012 mm s−1, and insulating index number 6800 s m−1, under a standard test with a heat flux of 2500 kW m−2 for 15 seconds.

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Section: Introductionmentioning

confidence: 99%

\frac{m ((), t)}{m_{0}} = 1 - ([], \frac{k_{g}}{k_{g} + k_{c}}) ({}, 1 - exp ((), - k_{p} t)) .

…”

Section: Introductionmentioning

confidence: 99%

“…Equation shows that as t → ∞, the residual mass approaches to an equilibrium value at constant temperature given by the following equation

\frac{m_{\infty}}{m_{0}} = ([], \frac{k_{c}}{k_{g} + k_{c}}) \equiv y_{c} .

…”

Section: Introductionmentioning

confidence: 99%

“…Assuming Arrhenius forms for k g ( k g = A g exp (− E g / RT )) and k c ( k c = A c exp (− E c / RT )) in Equation , it can be rewritten as follows:

y_{c} = y_{c} ((), T) = {[1 + \frac{A_{g}}{A_{c}} exp [- (E_{g} - E_{c}) / RT]]}^{- 1} .

…”

Section: Introductionmentioning

confidence: 99%

“…Substituting Equation into Equation yields the final results for the mass loss in the rate constant for thermolysis of primary chemical bonds in the polymer, k :

\frac{m ((), t)}{m_{\circ}} = y_{c} + ((), 1 - y_{c}) exp ((), - italickt) .

…”

Section: Introductionmentioning

confidence: 99%

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Ablation behavior of organoclay‐NBR insulator: Modeling and experimental

2018

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Analytical effective thermal conductivity model for colloidal porous composites and nanocomposites based on novolac/graphene oxide aerogels

Nazari

Allahbakhsh

Bahramian

2022

Intl J of Energy Research

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The performance of porous composite materials in thermal energy storage and management applications can be engineered by controlling the relationship between the heat transfer mechanism and the structure of these materials. Analytical thermal conductivity models are essential tools to study and manage such structure/heat transfer relations in porous composite materials. This study develops an analytical thermal conductivity model for porous composites with colloidal matrix morphologies. The model developed here is a modified series-parallel model that considers important structural parameters such as the system's porosity, the colloidal size of the matrix, and the filler's aspect ratio. Moreover, essential effects in the structure of porous composites, including the gas-solid coupling effect and contact length of particles, are also included in the model developed here. In addition, this model can be used in a wide range of porosity and can predict the thermal conductivity of porous composites with appropriate accuracy by changing temperature, pressure, specific surface area, porosity, and other textural properties. Novolac/graphene oxide nanocomposite aerogels with different contents of graphene oxide (GO) nanosheets in the structure were prepared and used to study the validity of the data calculated using the developed model. Our results confirmed that

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