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Ablative Material

The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

Lisong Zhang – 1st expert on this subject based on the ideXlab platform

  • measurement and theoretical prediction on the surface emittance of carbonized layer of silica phenolic Ablative Material
    International Journal of Heat and Mass Transfer, 2018
    Co-Authors: Hong Ye, Lisong Zhang

    Abstract:

    Abstract As a typical fiber reinforced resin-based Ablative Material, silica/phenolic composite has important applications in the thermal protection of high-speed aircrafts. At high temperature, it can form a carbonized layer, whose surface emittance is directly related to its capacity of radiative heat dissipation. In this work, carbonization experiments of the silica/phenolic composite and pure phenolic resin were designed to obtain their corresponding carbonized samples. The spectral emittances in the wavelength range from 2.5 to 25 μm of the carbonized samples were measured by a Fourier transform infrared spectroscopy with a blackbody furnace and a sample heater at temperatures from 200 to 500 °C. The results showed that the spectral emittance of the carbonized Ablative Material is close to that of the carbonized phenolic resin. The spectral emittances of the two carbonized samples increase with temperature and almost do not change with wavelength, indicating that the carbonized samples have the nature of a grey body. A prediction model of the total emittance was constructed based on the grey body assumption and a geometric model extracted from structure characterization of the carbonized Ablative Material. The predicted total emittances and those obtained from the integration of the measured spectral results are all higher than 0.8, and the deviations are below 10%. Theoretical predictions of the model show that the total emittance of the carbonized Ablative Material increases with the increasing porosity ( ϕ ) and total emittance ( e s ) of the fiber bundle covered with carbonized phenolic resin. Both the experimental and theoretical results reveal that the high total emittance of the carbonized silica/phenolic Ablative Material can be mainly attributed to the high emittance of the carbonized phenolic resin.

  • Measurement and theoretical prediction on the surface emittance of carbonized layer of silica/phenolic Ablative Material
    International Journal of Heat and Mass Transfer, 2018
    Co-Authors: Hong Ye, Lisong Zhang

    Abstract:

    Abstract As a typical fiber reinforced resin-based Ablative Material, silica/phenolic composite has important applications in the thermal protection of high-speed aircrafts. At high temperature, it can form a carbonized layer, whose surface emittance is directly related to its capacity of radiative heat dissipation. In this work, carbonization experiments of the silica/phenolic composite and pure phenolic resin were designed to obtain their corresponding carbonized samples. The spectral emittances in the wavelength range from 2.5 to 25 μm of the carbonized samples were measured by a Fourier transform infrared spectroscopy with a blackbody furnace and a sample heater at temperatures from 200 to 500 °C. The results showed that the spectral emittance of the carbonized Ablative Material is close to that of the carbonized phenolic resin. The spectral emittances of the two carbonized samples increase with temperature and almost do not change with wavelength, indicating that the carbonized samples have the nature of a grey body. A prediction model of the total emittance was constructed based on the grey body assumption and a geometric model extracted from structure characterization of the carbonized Ablative Material. The predicted total emittances and those obtained from the integration of the measured spectral results are all higher than 0.8, and the deviations are below 10%. Theoretical predictions of the model show that the total emittance of the carbonized Ablative Material increases with the increasing porosity ( ϕ ) and total emittance ( e s ) of the fiber bundle covered with carbonized phenolic resin. Both the experimental and theoretical results reveal that the high total emittance of the carbonized silica/phenolic Ablative Material can be mainly attributed to the high emittance of the carbonized phenolic resin.

  • investigation on the effective thermal conductivity of carbonized high silica phenolic Ablative Material
    International Journal of Heat and Mass Transfer, 2017
    Co-Authors: Yexin Xu, Hong Ye, Lisong Zhang

    Abstract:

    Abstract As a phenolic resin-based Ablative Material, high silica/phenolic composite is widely used in aerospace field. However, the effective thermal conductivity of carbonized Ablative Material formed during ablation process is rarely reported. In this work, carbonized sample of the high silica/phenolic Ablative Material was obtained by a carbonization process, and its effective thermal conductivity was measured from 100 to 970 °C. In addition, an analysis model of the effective thermal conductivity of the carbonized ablator consisting of fiber yarns and carbonized phenolic was established based on the result of structure analysis. The measured value of the effective thermal conductivity of the carbonized phenolic was used to inverse the transverse effective thermal conductivity of the fiber yarns. When the inversed values were adopted in different empirical models, it was found that the Clayton model is suitable for predicting the effective thermal conductivity of the carbonized high silica/phenolic.

Hong Ye – 2nd expert on this subject based on the ideXlab platform

  • measurement and theoretical prediction on the surface emittance of carbonized layer of silica phenolic Ablative Material
    International Journal of Heat and Mass Transfer, 2018
    Co-Authors: Hong Ye, Lisong Zhang

    Abstract:

    Abstract As a typical fiber reinforced resin-based Ablative Material, silica/phenolic composite has important applications in the thermal protection of high-speed aircrafts. At high temperature, it can form a carbonized layer, whose surface emittance is directly related to its capacity of radiative heat dissipation. In this work, carbonization experiments of the silica/phenolic composite and pure phenolic resin were designed to obtain their corresponding carbonized samples. The spectral emittances in the wavelength range from 2.5 to 25 μm of the carbonized samples were measured by a Fourier transform infrared spectroscopy with a blackbody furnace and a sample heater at temperatures from 200 to 500 °C. The results showed that the spectral emittance of the carbonized Ablative Material is close to that of the carbonized phenolic resin. The spectral emittances of the two carbonized samples increase with temperature and almost do not change with wavelength, indicating that the carbonized samples have the nature of a grey body. A prediction model of the total emittance was constructed based on the grey body assumption and a geometric model extracted from structure characterization of the carbonized Ablative Material. The predicted total emittances and those obtained from the integration of the measured spectral results are all higher than 0.8, and the deviations are below 10%. Theoretical predictions of the model show that the total emittance of the carbonized Ablative Material increases with the increasing porosity ( ϕ ) and total emittance ( e s ) of the fiber bundle covered with carbonized phenolic resin. Both the experimental and theoretical results reveal that the high total emittance of the carbonized silica/phenolic Ablative Material can be mainly attributed to the high emittance of the carbonized phenolic resin.

  • Measurement and theoretical prediction on the surface emittance of carbonized layer of silica/phenolic Ablative Material
    International Journal of Heat and Mass Transfer, 2018
    Co-Authors: Hong Ye, Lisong Zhang

    Abstract:

    Abstract As a typical fiber reinforced resin-based Ablative Material, silica/phenolic composite has important applications in the thermal protection of high-speed aircrafts. At high temperature, it can form a carbonized layer, whose surface emittance is directly related to its capacity of radiative heat dissipation. In this work, carbonization experiments of the silica/phenolic composite and pure phenolic resin were designed to obtain their corresponding carbonized samples. The spectral emittances in the wavelength range from 2.5 to 25 μm of the carbonized samples were measured by a Fourier transform infrared spectroscopy with a blackbody furnace and a sample heater at temperatures from 200 to 500 °C. The results showed that the spectral emittance of the carbonized Ablative Material is close to that of the carbonized phenolic resin. The spectral emittances of the two carbonized samples increase with temperature and almost do not change with wavelength, indicating that the carbonized samples have the nature of a grey body. A prediction model of the total emittance was constructed based on the grey body assumption and a geometric model extracted from structure characterization of the carbonized Ablative Material. The predicted total emittances and those obtained from the integration of the measured spectral results are all higher than 0.8, and the deviations are below 10%. Theoretical predictions of the model show that the total emittance of the carbonized Ablative Material increases with the increasing porosity ( ϕ ) and total emittance ( e s ) of the fiber bundle covered with carbonized phenolic resin. Both the experimental and theoretical results reveal that the high total emittance of the carbonized silica/phenolic Ablative Material can be mainly attributed to the high emittance of the carbonized phenolic resin.

  • investigation on the effective thermal conductivity of carbonized high silica phenolic Ablative Material
    International Journal of Heat and Mass Transfer, 2017
    Co-Authors: Yexin Xu, Hong Ye, Lisong Zhang

    Abstract:

    Abstract As a phenolic resin-based Ablative Material, high silica/phenolic composite is widely used in aerospace field. However, the effective thermal conductivity of carbonized Ablative Material formed during ablation process is rarely reported. In this work, carbonized sample of the high silica/phenolic Ablative Material was obtained by a carbonization process, and its effective thermal conductivity was measured from 100 to 970 °C. In addition, an analysis model of the effective thermal conductivity of the carbonized ablator consisting of fiber yarns and carbonized phenolic was established based on the result of structure analysis. The measured value of the effective thermal conductivity of the carbonized phenolic was used to inverse the transverse effective thermal conductivity of the fiber yarns. When the inversed values were adopted in different empirical models, it was found that the Clayton model is suitable for predicting the effective thermal conductivity of the carbonized high silica/phenolic.

Nagi N Mansour – 3rd expert on this subject based on the ideXlab platform

  • multidimensional Material response simulations of a full scale tiled Ablative heatshield
    Aerospace Science and Technology, 2018
    Co-Authors: Jeremie B E Meurisse, Jean Lachaud, Francesco Panerai, Chun Tang, Nagi N Mansour

    Abstract:

    Abstract The Mars Science Laboratory (MSL) was protected during Mars atmospheric entry by a 4.5 meter diameter heatshield, which was constructed by assembling 113 thermal tiles made of NASA’s flagship porous Ablative Material, Phenolic Impregnated Carbon Ablator (PICA). Analysis and certification of the tiles thickness were based on a one-dimensional model of the PICA response to the entry aerothermal environment. This work provides a detailed three-dimensional heat and mass transfer analysis of the full-scale MSL tiled heatshield. One-dimensional and three-dimensional Material response models are compared at different locations of the heatshield. The three-dimensional analysis is made possible by the use of the Porous Material Analysis Toolbox based on OpenFOAM (PATO) to simulate the Material response. PATO solves the conservation equations of solid mass, gas mass, gas momentum and total energy, using a volume-averaged formulation that includes production of gases from the decomposition of polymeric matrix. Boundary conditions at the heatshield forebody surface were interpolated in time and space from the aerothermal environment computed with the Data Parallel Line Relaxation (DPLR) code at discrete points of the MSL trajectory. A mesh consisting of two million cells was created in Pointwise, and the Material response was performed using 840 processors on NASA’s Pleiades supercomputer. The present work constitutes the first demonstration of a three-dimensional Material response simulation of a full-scale Ablative heatshield with tiled interfaces. It is found that three-dimensional effects are pronounced at the heatshield outer flank, where maximum heating and heat loads occur for laminar flows.

  • toward Ablative Material response coupling in dplr
    11th AIAA ASME Joint Thermophysics and Heat Transfer Conference, 2014
    Co-Authors: Suman Muppidi, Michael Barnhardt, Nagi N Mansour

    Abstract:

    The present paper describes preliminary development of an in-depth Material response model within NASA’s DPLR software. A complete description of the formulation of a fluid-coupled, Ablative Material response model is provided. The model accounts for finiterate chemistry and convection of pyrolysis gases through a porous medium. The Material response equations are implemented in DPLR to produce a structured solver, which is implemented on a parallel computing platform. An independent coupling interface allows the new DPLR-ARM code to communicate boundary data with DPLR, enabling coupled simulations of fluid and Material response. A preliminary demonstration of the feasibility of this approach is presented by analysis of two conduction-only problems: a titanium ballistic range projectile, and a carbon ablator subject to low heat flux in an arc jet. Results of the simulations show that proper characterization of Material properties, such as surface emissivity, and the non-isotropy and temperature dependence of thermal conductivity, have a strong influence on the predicted temperature field. Additionally, it is found that the solution is sensitive to frequency of data exchange in the coupling procedure.

  • Porous-Material Analysis Toolbox Based on OpenFOAM and Applications
    Journal of Thermophysics and Heat Transfer, 2014
    Co-Authors: Jean Lachaud, Nagi N Mansour

    Abstract:

    The Porous-Material Analysis Toolbox based on OpenFOAM is a fully portable OpenFOAM library. It is implemented to test innovative multiscale physics-based models for reacting porous Materials that undergo recession. Current developments are focused on Ablative Materials. The Ablative Material response module implemented in the Porous-Material Analysis Toolbox relies on an original high-fidelity ablation model. The governing equations are volume-averaged forms of the conservation equations for gas mass, gas species, solid mass, gas momentum, and total energy. It may also simply be used as a state-of-the-art ablation model when the right model options are chosen. As applications, three physical analyses are presented: 1) volume-averaged study of the oxidation of a carbon-fiber preform under dry air, 2) three-dimensional analysis of the pyrolysis gas flow in a porous Ablative Material sample facing an arcjet, and 3) comparison of a state-of-the-art and a high-fidelity model for the thermal and chemical respo…