Fig. 39.3. Typical Convective cooling system.

In ‘ablation’ type active cooling, a layer of ablative material is coated over the surface to be protected. The protective layer melts and vaporizes due to heat load absorbing large amount of thermal energy. A typical ‘ablation cooling’ system is shown in Fig. 39.4. Graphite and phenolic materials are currently popular ones for ablative materials. It is also found that the vehicle can be cooled efficiently by transferring coolant mass in the boundary layer from its surface.

Fig. 39.4 Ablation cooling system.