A New Thermal Protection System by Opposing Jet for Reusable Launch Vehicle
- Paper number
IAC-05-D2.5.10
- Author
Mr. Kentaro Hayashi, Mistubishi Space Software Co. Ltd., Japan
- Coauthor
Prof. Shigeru Aso, Kyushu University, Japan
- Coauthor
Dr. Yasuhiro Tani, Kyushu University, Japan
- Year
2005
- Abstract
Recently, developments of RLV (Reusable Launch Vehicle) are in progress. For future space developments, they are necessary in order to decrease costs for space transportation systems. In the developments of RLV, one of the most important problems is the severe aerodynamic heating at nose of the vehicle in supersonic and re-entry flight. Therefore accurate prediction of aerodynamic heating and construction of proper TPS (Thermal Protection System) are required. Although current TPS such as heat resistant tiles have reusability, maintenance cost is high. For this reason, RLV requires simple and low cost TPS. Therefore we propose a new thermal protection system by opposing jet. Injection point of this TPS is located at stagnation point and jet blows toward free stream and then jet flow reattaches to the body. The TPS by opposing jet can protect a nose of the body by aerodynamic spike, and also protect downstream region by covering the surface. According to this effect, TPS by opposing jet can protect a body of RLV and we can construct a reusable thermal protection system. We investigate performance of TPS by opposing jet and invent efficient cooling method. For this purpose, we study detail physical mechanism of reduction of heat flux. For these objectives, we have studied TPS by opposing jet by using wind tunnel test and CFD. A blunt body model is used in order to simulate stagnation region of nose and wing of RLV. In the present study, free stream Mach number is 4 and coolant gas is nitrogen. Surface heat flux around the nose region is measured by calorimeter technique in experiments. Flow around the model is visualized by the Schlieren method. In numerical analysis, axisymmetric full Navier-Stokes equations are used as governing equations with k-omega turbulence model. Results of wind tunnel test show remarkable reduction of heat flux. Even negative heat flux is observed around injection point. As an amount of coolant gas is increased, the heat flux is decreased at each point. Especially, the amount of coolant gas affects the heat flux at nose region. Numerical results show good agreement with experiments. From the visualizations of the flow field and the heat flux distribution, it becomes clear that the recirculation region plays an important role for a reduction of heat flux. High velocity and low temperature region near the wall is observed in the recirculation region. It became clear that surface heat flux is decreased by this low temperature region. In conclusion, compared with another TPS such as heat resistant tiles and film cooling etc., thermal protection system by opposing jet has great advantage for protection at stagnation region.
- Abstract document
- Manuscript document
IAC-05-D2.5.10.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.