Thermochemical Performance of a Lightweight Charring Carbon Fiber Reinforced Plastic

Abstract

A new class of lightweight carbon fiber reinforced plastic (CFRP)-the lightweight ablator series for transfer vehicle systems (LATS)-has recently been developed. The LATS is fabricated by heating and pressurizing a material in which resin is impregnated in the laminated carbon fiber felt. A characteristic required to ensure the excellence of a conventional lightweight CFRP ablator of the LATS is the simplicity of the resin impregnation process. Since dried bulk density can be easily controlled, this manufacturing method is beneficial for use in the aerospace industry. Here, the ablation characteristics of this material under high-enthalpy airflow are described by a recently developed computer code to simulate the one-dimensional transient thermal behavior. The validity of the mathematical model and the applicability of the ablation code are then discussed by comparing the simulated and experimental results of arc-heated tests with the LATS. A new index adopted in this study predicted the mass loss rate; the measured and estimated values of the total mass loss rate in various test conditions are in good agreement. Thus, a heated LATS material shows excellent performance characteristics for use in re-entry vehicles, and its surface and in-depth temperatures can be estimated using the developed analysis code.

Study of the Effects of Density, Thickness and Heat Load on Heat Shielding Performance of Phenolic Carbon Ablators Using a One-Dimensional Ablation Analysis Code

“…The char density for each ablator model is calculated by means of the following relation based on the measurement of virgin and charred materials. 7) 7 . 0 v ch (7) The emissivity of the char surface was set to be 0.85.…”

“…7) 7 . 0 v ch (7) The emissivity of the char surface was set to be 0.85. 8,12) The reference value of thermal conductivity of the virgin material kvref is constructed of the measured value of the LATS materials with the density of about 300 kg/m 3 , using a steady-state method with the temperature range from room temperature (RT) to 573 K (300 o C), combined with the literature data 4) of the low density (about 300 kg/m 3 ) ablator (PICA) multiplied by a constant value, C*kvPICA(T), where kvPICA(T) is the thermal conductivity of the PICA and C is a constant value that is determined so that the two data are smoothly connected.…”

“…Recently, a lightweight ablator named LATS (Lightweight Ablator series for Transfer vehicle Systems) with the densities of about 300-700kg/m 3 has been developed. 6,7) The LATS is a carbon phenolic ablator fabricated by impregnating a phenolic resin into a felt made of carbon fibers. The material properties of the LATS ablator were measured and arc-heated tests of the ablator samples with various densities were carried out.…”

Study of the Effects of Heat Load, Ablator Density and Backup Structure upon the Thermal Protection Performance of Heat Shield Systems Consisting of Phenolic Carbon Ablators

“…The material properties of the LATS ablator were measured and arc-heated tests of the ablator samples with various densities were carried out. 9,10) Ablation analysis with respect to the arc-heated tests was also carried out using a onedimensional analysis code and the measured and calculation results agreed well. 10,11) Investigations concerning the effects of heat load and ablator density upon the necessary thickness tne and necessary mass mne of the LATS ablator were carried out using a one-dimensional ablation analysis code.…”

“…9) The LATS is a carbon phenolic ablator fabricated by impregnating a phenolic resin into a felt made of carbon fibers. The material properties of the LATS ablator were measured and arc-heated tests of the ablator samples with various densities were carried out.…”