Thermal Response Simulation of Ultra Light Weight Phenolic Carbon Ablator by the Use of the Ablation Analysis Code

Abstract

A space vehicle which undergoes the atmospheric re-entry or a planetary entry needs the heat shield system to protect inner equipments against severe aerodynamic heating environments. Charring ablator is usually used for the heat shield system. In order to design the heat shield system, it is necessary to predict the thermal behavior under aerodynamic heating by ablation analysis. A computer code for charring ablation and thermal response analysis is newly developed for simulation of one-dimensional transient thermal behavior of charring ablation materials. The mathematical model for the charring ablation including basic equation and computational method of ablation analysis is briefly described. A new ultra light weight phenolic carbon ablator called LATS (Lightweight Ablator series for Transfer vehicle) was recently developed. Arc-heated tests of the LATS ablator were carried out and measured results of the temperature response and surface mass loss are compared with the simulation results of the ablation analysis program. The agreement between the results of simulation and measurement is found to be good. It is also found that the mathematical model used in the ablation code can be applied to the ablation analysis of the low density LATS ablator.

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

“…Mathematical model of ablation, input data for the ablation analysis and the analysis conditions for the parametric study are shown in the following sections. 10,11) A one-dimensional computer code for charring ablation and thermal response analysis was used to calculate the heat resistant performance of the LATS ablators. The code was developed for simulation of one-dimensional transient thermal behavior of charring materials, and was successfully applied to the LATS ablators under the heating environments of arc-heated test.…”

“…Cpg and hpyro are assumed to be constant values of 1674.6 J/(kg K) and 3.313�10 5 J/kg, respectively. 10,11) For each time step, output parameters are obtained simultaneously for both the ablator and the backup wall.…”

“…[10][11][12][13][14][15][16] The in-depth governing equations for onedimensional charring ablator response are energy, mass continuity, and decomposition equations, and are expressed by…”

“…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.…”

“…9,10) 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. 11) It was found that the necessary thickness tne is nearly constant as the ablator density changes, and the necessary mass mne increases almost linearly with the increase of the density.…”