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Poloni E, Grigat F, Eberhart M, Leiser D, Sautière Q, Ravichandran R, Delahaie S, Duernhofer C, Hoerner I, Hufgard F, Loehle S. An open carbon-phenolic ablator for scientific exploration. Sci Rep 2023; 13:13135. [PMID: 37573464 PMCID: PMC10423272 DOI: 10.1038/s41598-023-40351-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/09/2023] [Indexed: 08/14/2023] Open
Abstract
Space exploration missions rely on ablative heat shields for the thermal protection of spacecraft during atmospheric entry flights. While dedicated research is needed for future missions, the scientific community has limited access to ablative materials typically used in aerospace. In this paper, we report the development of the HEFDiG Ablation-Research Laboratory Experiment Material (HARLEM), a carbon-phenolic ablator designed to supply the need for ablative materials in laboratory experiments. HARLEM is manufactured using polyacrylonitrile-based carbon fiber preforms and a simplified processing route for phenolic impregnation. We characterized the thermal protection performance of HARLEM in arcjet experiments conducted in the plasma wind tunnel PWK1 of the Institute of Space Systems at the University of Stuttgart. We assessed the performance of the new material by measuring surface recession rate and temperature using photogrammetry and thermography setups during the experiments, respectively. Our results show that HARLEM's thermal protection performance is comparable to legacy carbon-phenolic ablators that have been validated in different arcjet facilities or in-flight, as demonstrated by calculations of the effective heat of ablation and scanning electron microscopy of as-produced samples. In-house manufacturing of carbon-phenolic ablators enables the addition of embedded diagnostics to ablators, allowing for the acquisition of data on internal pressure and more sophisticated pyrolysis analysis techniques.
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Affiliation(s)
- Erik Poloni
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany.
- Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, London, SW7 2AZ, UK.
| | - Felix Grigat
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - Martin Eberhart
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - David Leiser
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - Quentin Sautière
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - Ranjith Ravichandran
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
- Vikram Sarabhai Space Center, Indian Space Research Organisation, Thiruvananthapuram, 695022, India
| | - Sara Delahaie
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - Christian Duernhofer
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - Igor Hoerner
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - Fabian Hufgard
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
| | - Stefan Loehle
- High Enthalpy Flow Diagnostics Group, Institute of Space Systems, University of Stuttgart, 70569, Stuttgart, Germany
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Hufgard F, Duernhofer C, Fasoulas S, Loehle S. Novel heat flux controlled surface cooling for hypersonic flight. Sci Rep 2023; 13:13109. [PMID: 37568038 PMCID: PMC10421943 DOI: 10.1038/s41598-023-40281-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 08/08/2023] [Indexed: 08/13/2023] Open
Abstract
This paper presents a new method in theory and experiment to adjust the transpiration cooling based on the actual measured heat flux. This is particularly useful in extreme heating environments, e.g. atmospheric entry flight or combustion chamber applications. In such environments, usually cooling is set constant based on the vehicle design, yet a mass efficient and performant cooling is sought after. We present a method with real-time surface heat flux determination of the transpiration cooled wall and an automatic adjustment of the cooling. The heat flux is determined based on a system identification process. The heat flux measurement itself is derived non-intrusively from the measurement of pressure inside the plenum, i.e. the region between mass flow controller and porous wall. The particular advantage of this system is that the heat shield material is not weakened by any sensor system and its performance is optimized with respect to cooling needed at a certain heating level. Another new feature of the pressure heat flux transformation is the attenuation of a destabilizing positive feedback loop, where the transpiration cooling controller's output (i.e. mass flow rate) strongly influences its input (i.e. plenum pressure). We describe the identification of the model parameters for the heat flux determination, which are found and verified by a calibration approach. The controlled cooling was demonstrated in a hot air plasma flow with a reference heat flux of up to 1.4 MW/m[Formula: see text]. The results show the performance and verify the applicability in a real flight environment.
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Affiliation(s)
- Fabian Hufgard
- High Enthalpy Flow Diagnostics Group (HEFDiG), Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, 70569, Stuttgart, Germany.
| | - Christian Duernhofer
- High Enthalpy Flow Diagnostics Group (HEFDiG), Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, 70569, Stuttgart, Germany
| | - Stefanos Fasoulas
- High Enthalpy Flow Diagnostics Group (HEFDiG), Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, 70569, Stuttgart, Germany
| | - Stefan Loehle
- High Enthalpy Flow Diagnostics Group (HEFDiG), Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, 70569, Stuttgart, Germany
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