Influence Of Structural Parameters On Heat Transfer Properties Of Silicone Resin-coated Fabrics

Organic silicon resin-coated fabrics have important applications in thermal protection systems for space vehicles due to their light weight,softness,and good ablative heat resistance.In order to predict the thermal insulation performance of coated carbon fiber fabric,a numerical heat transfer model under high temperature was established.The simulation results have been validated by quartz lamp ablation experiment.Furthermore,the impact of structural parameters on the thermal insulation of coated fiber fabrics,by using the numerical heat transfer model,was investigated.The results are shown below:（1）The experimental data were in agreement with the numerical data,and average relative error between them is 9.47%.（2）In the case where the thickness of the coating is unchanged and the total thickness changes with the thickness of the fabric,the change law of the coated carbon fiber fabric is as follows:when the density and yarn fineness are constant,the insulation performance of the samples after 135s are 5/3 stain>3/3 twill>2/1 twill>plain.When the fineness of carbon fiber is increased from 3K to 12K,the temperature of the back surface of the coated carbon fabric with yarn fineness of 12K is 52℃ lower than that of the coated carbon fabric with yarn fineness of 3 K,and the heat insulation performance is enhanced.With an increase of structure density from 40（ends/10cm）/40（picks/10cm） to 70（ends/10cm）/70（picks/10cm）,the temperature on the back surface of the coated fabrics decreases from 626℃ to 595℃.They differ by 31℃,indicating that the structure density of 70（ends/10cm）/70（picks/10cm）has a better insulation performance.（3）In the case where the coating thickness is unchanged and the total thickness changes with the thickness of the fabric,the change law of the coated glass fiber fabric is as follows:when the density and yarn fineness are constant,the insulation performance of the samples after 135s are 5/3 stain>3/3 twill>2/1 twill>plain.when the warp density increases from 100 ends/10cm to 180 end/10cm,the temperature of the back surface of the coated fabric decreases gradually and the thermal insulation is more effective.And the relationship between the temperature and the warp density can be described by the regression model as follows T₁=758.96446-2.16398X₁+0.00568X²₁.With an increase of weft density from 100 picks/10cm to160 picks/10cm,the temperatures of the back surface of the coated glass fabrics were gradually decreased from 574℃ to 555℃ after 115s,and the temperature difference was 19℃.When the weave pattern,structure density are same,the temperature values of the back surface of the coated glass fiber fabrics after 115s are 129 tex>160 tex>198 tex>220 tex>280 tex.And the relationship between the temperature and the yarn fineness can be described by a linear regression model T₂=665.63886-0.39418X₂.（4）Under the condition that the total thickness of the coated fabric is the same,when the fabric density and yarn fineness are not changed,the temperature of the back of the coated carbon fiber fabric and coated glass fiber fabric of different organizations is as follows:plain<2/1 twill<3/3 twill<5/3 satin.When the density or fineness of the coated carbon fiber fabric or coated glass fiber fabric changes,the thickness of the fabric is smaller and the heat insulation performance is better.