Numerical simulation of transpiration cooling for a high-speed boundary layer undergoing transition to turbulence
Numerical simulation of transpiration cooling for a high-speed boundary layer undergoing transition to turbulence
Cooling the surface of high-speed vehicles by injection of coolant into the flow stream aims to reduce the overall weight and cost of thermal protection systems. Here, the transpiration-based cooling method is studied for a Mach number M∞ = 5 with coolant injected through a porous layer composed of a staggered arrangement of spheres. Disturbances are introduced into the boundary layer upstream of the porous layer to study in detail the flow regime in which the boundary layer is transitional, including cases where transition is triggered either downstream or directly over the sample. The present work evaluates the effects of transition location, Reynolds number at injection location, and blowing ratio on the cooling performance downstream of the porous sample with heat fluxes that are comparable in magnitude to those seen in laboratory experiments. Flow within the porous layer is found to be unsteady, with a non-negligible streamwise pressure gradient introduced by shock and expansion waves at the leading and trailing edge of the porous sample. For cases where transition occurs just downstream of the sample, the lowest pressure/blowing ratio case results in more cooling immediately after the porous layer, but cooling performance worsens farther downstream. Higher blowing ratio cases show higher effectiveness for a longer distance downstream, despite the transition location moving upstream. For cases where transition occurs over the porous sample, the cooling effect is more consistent, with the heat flux decreasing monotonically with increasing pressure/blowing ratio. The results not only show a strong dependence on transition location, but also that opposite trends in cooling performance are possible when transition occurs just downstream of the injection.
High speed flows, Porous layer, Transition to turbulence, transpiration cooling, Transpiration cooling
Sharma, Pushpender K.
31c7280b-e564-46cb-ad1a-bb7fa00f3887
Deiterding, Ralf
ce02244b-6651-47e3-8325-2c0a0c9c6314
Cerminara, Adriano
6d8dd4dc-ace5-4a6d-92bd-16ef94b5c87d
Sandham, Neil
0024d8cd-c788-4811-a470-57934fbdcf97
October 2023
Sharma, Pushpender K.
31c7280b-e564-46cb-ad1a-bb7fa00f3887
Deiterding, Ralf
ce02244b-6651-47e3-8325-2c0a0c9c6314
Cerminara, Adriano
6d8dd4dc-ace5-4a6d-92bd-16ef94b5c87d
Sandham, Neil
0024d8cd-c788-4811-a470-57934fbdcf97
Sharma, Pushpender K., Deiterding, Ralf, Cerminara, Adriano and Sandham, Neil
(2023)
Numerical simulation of transpiration cooling for a high-speed boundary layer undergoing transition to turbulence.
Aerospace Science and Technology, 141, [108581].
(doi:10.1016/j.ast.2023.108581).
Abstract
Cooling the surface of high-speed vehicles by injection of coolant into the flow stream aims to reduce the overall weight and cost of thermal protection systems. Here, the transpiration-based cooling method is studied for a Mach number M∞ = 5 with coolant injected through a porous layer composed of a staggered arrangement of spheres. Disturbances are introduced into the boundary layer upstream of the porous layer to study in detail the flow regime in which the boundary layer is transitional, including cases where transition is triggered either downstream or directly over the sample. The present work evaluates the effects of transition location, Reynolds number at injection location, and blowing ratio on the cooling performance downstream of the porous sample with heat fluxes that are comparable in magnitude to those seen in laboratory experiments. Flow within the porous layer is found to be unsteady, with a non-negligible streamwise pressure gradient introduced by shock and expansion waves at the leading and trailing edge of the porous sample. For cases where transition occurs just downstream of the sample, the lowest pressure/blowing ratio case results in more cooling immediately after the porous layer, but cooling performance worsens farther downstream. Higher blowing ratio cases show higher effectiveness for a longer distance downstream, despite the transition location moving upstream. For cases where transition occurs over the porous sample, the cooling effect is more consistent, with the heat flux decreasing monotonically with increasing pressure/blowing ratio. The results not only show a strong dependence on transition location, but also that opposite trends in cooling performance are possible when transition occurs just downstream of the injection.
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More information
Accepted/In Press date: 14 August 2023
e-pub ahead of print date: 22 August 2023
Published date: October 2023
Additional Information:
Funding Information:
The authors would like to acknowledge support from EPSRC (Engineering and Physical Sciences Research Council) under Grant No. EP/P000878/1 . The authors also acknowledge the use of the IRIDIS High Performance Computing Facility, and associated support services at the University of Southampton, to accomplish this work.
Funding Information:
The authors would like to acknowledge support from EPSRC (Engineering and Physical Sciences Research Council) under Grant No. EP/P000878/1. The authors also acknowledge the use of the IRIDIS High Performance Computing Facility, and associated support services at the University of Southampton, to accomplish this work.
Publisher Copyright:
© 2023 The Author(s)
Keywords:
High speed flows, Porous layer, Transition to turbulence, transpiration cooling, Transpiration cooling
Identifiers
Local EPrints ID: 481194
URI: http://eprints.soton.ac.uk/id/eprint/481194
ISSN: 1270-9638
PURE UUID: c4aa322d-2990-4afc-b5df-1fc97d4e2a77
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Date deposited: 18 Aug 2023 16:34
Last modified: 18 Mar 2024 03:59
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Author:
Adriano Cerminara
Author:
Neil Sandham
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