Thermal Management

Generally, an object immersed in a flowing gas experiences some amount of heat transfer. As the speed increases, heat transfer becomes more significant. In the case of hypersonics, heat transfer is very significant with the strong shocks resulting in high-temperature flow leading to heat transfer from the flow into the vehicle called aerodynamic heating. Aerodynamic heating is such a concern in hypersonics, that it dictates the configuration of most vehicle shapes. Even within hypersonics, the shape of the vehicle can greatly affect the type of flow phenomena present. For example, the figure below shows the X-43A that flew at Mach 9.68 with a slender shape and sharp leading edges. However, the second figure below shows another vehicle that also traveled at hypersonic speeds: the Space Shuttle Discovery that traveled at Mach 25, both during atmospheric reentry. The shape differences arise from whether drag is to be maximized or minimized. For reentry flight, deceleration through drag is vital requiring much blunter shapes such as the Space Shuttle. However, for hypersonic cruise and acceleration vehicles, such as the X-43A, drag is minimized in order to maximize the range, which results in high convective heat rates.

X-43

NASA Illustrations
Space Shuttle Discovery

NASA

Electron transpiration cooling is a novel thermal management approach that are group has been working on:

Here is a story on a bio-inspired thermal management approach:

Below is our work on thermal management approaches: