Major research outcome
- Professor Jae-Hung Han’s Lab Presents Next-Generation Thermal Protection Technology Utilizing Transpiration Cooling
- 관리자 |
- 2026-03-04 00:15:18|
- 169
- 2026-03-04 00:15:18|
In the "New Space" era, there is a rapidly growing demand for reusable space vehicles that can significantly reduce costs and perform sustainable missions compared to conventional launch vehicles. During atmospheric reentry, these vehicles face extreme aerodynamic heating on their exterior due to the adiabatic compression effect caused by shock waves. Consequently, Thermal Protection Systems (TPS) are essential to prevent structural deformation or failure under such high heat flux environments.
Traditional TPS, which utilize insulation or ablation, require periodic replacement. Inspecting and repairing thousands of individual thermal tiles after reentry consumes immense time and maintenance costs. Furthermore, these systems have inherent limitations in completely blocking heat that penetrates through the gaps between tiles.
In contrast, transpiration cooling is a method where a coolant is forced through a porous medium to form a thin protective coolant film on the structure's surface. This film not only withstands extreme thermal loads stably but also seamlessly covers and protects structural gaps that are difficult to shield with conventional tile methods. This technology is gaining significant attention as a core solution for securing both the economic feasibility and safety of next-generation spacecraft by enabling full reusability without structural damage.
However, existing porous media based on sintered metals or composites have irregular internal pore structures, leading to non-uniform coolant distribution. Specifically, the 'Vapor Blockage' phenomenon, in which vaporizing coolant sharply increases internal flow resistance, has been a major drawback, causing flow instability, localized overheating, and degraded cooling performance.
To overcome these limitations, the Space Structures and Hardware Systems Laboratory (SSHS) at the KAIST Department of Aerospace Engineering (Professor: Jae-Hung Han) introduced 3D-printed lattice structures. The research team conducted a detailed analysis of how coolant temperature influences vapor formation and flow instability.
Through this research, the team provided a clear interpretation of the Vapor Blockage phenomenon from both structural and fluid dynamics perspectives. This analysis moves beyond previous discussions that were limited to qualitative observations. The team established specific design and operational criteria for lattice structures to ensure stable thermal protection. The results demonstrated that cooling efficiency can be improved by up to 95% when vapor formation is suppressed through optimized conditions. This achievement is expected to serve as pivotal reference data for designing active TPS for future reusable spacecraft and hypersonic vehicles.
This research was published in the February 2026 issue (Vol. 40, No. 2) of the Journal of Mechanical Science and Technology (JMST) and was honored as the Editor’s Pick for that issue.
(Left) Schematic of transpiration cooling and its application areas on a space vehicle.
(Right) Images of lattice structure geometry and cooling performance according to coolant temperature control.
Traditional TPS, which utilize insulation or ablation, require periodic replacement. Inspecting and repairing thousands of individual thermal tiles after reentry consumes immense time and maintenance costs. Furthermore, these systems have inherent limitations in completely blocking heat that penetrates through the gaps between tiles.
In contrast, transpiration cooling is a method where a coolant is forced through a porous medium to form a thin protective coolant film on the structure's surface. This film not only withstands extreme thermal loads stably but also seamlessly covers and protects structural gaps that are difficult to shield with conventional tile methods. This technology is gaining significant attention as a core solution for securing both the economic feasibility and safety of next-generation spacecraft by enabling full reusability without structural damage.
However, existing porous media based on sintered metals or composites have irregular internal pore structures, leading to non-uniform coolant distribution. Specifically, the 'Vapor Blockage' phenomenon, in which vaporizing coolant sharply increases internal flow resistance, has been a major drawback, causing flow instability, localized overheating, and degraded cooling performance.
To overcome these limitations, the Space Structures and Hardware Systems Laboratory (SSHS) at the KAIST Department of Aerospace Engineering (Professor: Jae-Hung Han) introduced 3D-printed lattice structures. The research team conducted a detailed analysis of how coolant temperature influences vapor formation and flow instability.
Through this research, the team provided a clear interpretation of the Vapor Blockage phenomenon from both structural and fluid dynamics perspectives. This analysis moves beyond previous discussions that were limited to qualitative observations. The team established specific design and operational criteria for lattice structures to ensure stable thermal protection. The results demonstrated that cooling efficiency can be improved by up to 95% when vapor formation is suppressed through optimized conditions. This achievement is expected to serve as pivotal reference data for designing active TPS for future reusable spacecraft and hypersonic vehicles.
This research was published in the February 2026 issue (Vol. 40, No. 2) of the Journal of Mechanical Science and Technology (JMST) and was honored as the Editor’s Pick for that issue.
(Left) Schematic of transpiration cooling and its application areas on a space vehicle.
(Right) Images of lattice structure geometry and cooling performance according to coolant temperature control.
Paper Title: Experimental investigation into the effect of coolant temperature on transpiration cooling in lattice structures DOI: https://doi.org/10.1007/s12206-026-0158-4
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