Pushpender K. Sharma, Ralf Deiterding, Neil Sandham
DOI Number XXX-YYY-ZZZ
Conference Number HiSST-2022-421
The strategy of transpiration-based cooling is explored where the coolant is injected into the hypersonic
cross-flow using a porous layer, providing a gradual and more uniform distribution of the coolant into the
boundary layer and hence higher effectiveness. In the present numerical study, three-dimensional direct
numerical simulations of flow past a flat plate with a porous layer are conducted at M = 5. A conjugate
heat flux boundary condition is used as compared to a simpler isothermal wall. The coolant is injected
through a porous layer that is numerically represented as a staggered arrangement of spheres, which
requires the utilization of smaller pressure ratios similar to that in the corresponding actual experiments.
Also, to mimic the background disturbances intrinsic to the experiments, wall-bounded disturbances are
introduced upstream of the porous layer such that reasonable mixing of coolant is allowed inside the
hypersonic boundary layer. Flow transition is noted to play a critical role in the performance. It is noted
from the first set of moderately high injection Reynolds number cases that the lowest blowing ratio
results in more cooling immediately downstream of the porous layer, while the highest blowing ratio
shows overall best results, with highest cooling effectiveness even farther downstream among all the
blowing cases. For the second set of slightly higher injection Reynolds number cases, the trend is much
more monotonous, with increasing blowing ratios providing increasingly better effectiveness.