Optimization of multilayer thermal protection system by using phase change material under aerodynamic heating

Author(s):  
X.M. Ren ◽  
Hong Nie ◽  
Ming Zhang
2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4049-4059 ◽  
Author(s):  
Haythem Shili ◽  
Kamel Fahem ◽  
Souad Harmand ◽  
Jabrallah Ben

As part of the research in the field of thermal control of electronic components, a phase change material is confined in a liquid and is heated vertically on one side by a hot plate. The presence of the liquid around the phase change material prevents the formation of air bubbles produced in case of direct contact between the hotplate and the phase change material (extends the lifetime of the phase change material by reducing overheating zones). It improves heat transfer by increasing the thermal conductivity around the phase change material (raising the thermal exchange surface) and by accelerating the convective transfer. This work examines experimentally and numerically the effect of the water on the phase change material and on the heating plate. The water is used around the phase change material and a comparative study of the comportment of some important parameters like the melt front form, melting time, flow direction, temperature, and operating time is realized. It is found that the presences of the liquid around the phase change material seems to be more interesting for a thermal protection role than the standard case of the phase change material directly heated by the hotplate.


Author(s):  
Jeswin Joseph ◽  
S. R. Shine

Very high thermal loads are expected in re-entry vehicles traveling at hypersonic Mach numbers due to severe aerodynamic heating. In the present study, numerical investigations are carried out to analyze the use of film cooling technology for a fully reusable and active thermal protection system of the re-entry vehicle. Simulations are done to examine the fundamental flow phenomenon and the performance of blunt body film cooling in hypersonic flows. Simulations are conducted for a blunt -nosed spacecraft flying at Mach numbers varying from 4 to 8 and 40 deg angle of attack. Film cooling holes are provided on the bottom of the blunt-nosed body. Standard values at an altitude of 30 km are used as in flow boundary conditions. The dependency of blowing ratios, stream-wise injection angle and inlet Mach number on the film cooling effectiveness are investigated. It is observed that the film cooling effectiveness reduces with increase in coolant injection angle. The film cooling performance is found to be decreasing with increase in Mach number. The results could provide useful inputs for optimization of an active thermal protection system of re-entry vehicles.


2019 ◽  
Vol 9 (24) ◽  
pp. 5541 ◽  
Author(s):  
Vinh Tung Le ◽  
Nam Seo Goo

A skin structure for thermal protection is one of the most interesting components that needs to be considered in the design of a hypersonic vehicle. The thermal protection structure, if a dense structure is used, is heavy and has a large heat conduction path. Thus, a lightweight, high strength structure is preferable. Currently, for designing a lightweight structure with high strength, natural materials are of great interest for achieving low density, high strength, and toughness. This paper presents bio-inspired lightweight structures that ensure high strength for a thermal protection system (TPS). A sinusoidal shape inspired by the microstructure of the dactyl club of Odontodactylus scyllarus, known as the peacock mantis shrimp, is presented with two different geometries, a unidirectionally corrugated core sandwich structure (UCS) and a bidirectionally corrugated core sandwich structure (BCS). Thermomechanical analysis of the two corrugated core structures is performed under simulated aerodynamic heating, and the total deflection and thermal stress are presented. The maximum deflection of the present sandwich structure throughout a mission flight was 1.74 mm for the UCS and 2.04 mm for the BCS. Compared with the dense structure used for the skin structure of the TPS, the bio-inspired corrugated core sandwich structures achieved about a 65% weight reduction, while the deflections still satisfied the limits for delaying the hypersonic boundary layer transition. Moreover, we first fabricated the BCS to test the thermomechanical behaviors under a thermal load. Finally, we examined the influence of the core thickness, face-sheet thickness, and emittance in the simulation model to identify appropriate structural parameters in the TPS optimization. The present corrugated core sandwich structures could be employed as a skin structure for metallic TPS panels instead of the honeycomb sandwich structure.


Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2164
Author(s):  
H.M. Shih ◽  
Yi-Pin Lin ◽  
L.P. Lin ◽  
Chi-Ming Lai

In this study, a heat management module containing a microencapsulated phase change material (mPCM) was fabricated from mPCM (core material: paraffin; melting temperature: 37 °C) and aluminum honeycomb structures (8 mm core cell). The aluminum honeycomb functioned both as structural support and as a heat transfer channel. The thermal management performance of the proposed module under constant-temperature boundary conditions was investigated experimentally. The thermal protection period of the module decreased as the Stefan number increased; however, increasing the subcooling factor could effectively enhance the thermal protection performance. When the cold-wall temperature TC was fixed at 17 °C and the initial hot wall temperature was 47–67 °C, the heat dissipation of the module was complete 140 min after the hot-wall heat supply was stopped. The time required to complete the heat dissipation increased to 280 min when TC increased to 27 °C.


2012 ◽  
Vol 710 ◽  
pp. 594-599
Author(s):  
S. Hari Krishna ◽  
Ajay Kumar ◽  
P. Karthikeyan ◽  
M.P. Abilash ◽  
N. Narayanankutty ◽  
...  

Space vehicles that re-enter earth’s atmosphere require thermal protection system (TPS) to safeguard them from intense aerodynamic heating. Depending on the type of re-entry (lifting/ballistic), trajectory, duration of flight in atmospheric regime etc., the heat flux may vary from 40kW/m2to 180kW/m2. In our studies on metallic TPS (MTPS), corrugated core is joined to either side of the skins by brazing. The brazed joint is evaluated using both pulsed thermography (PT) and ultrasonic testing. PT images show clear visualization of joint and defects. Also it is faster and easier. Ultrasonic testing is done using pitch-catch and pulse-echo techniques, which shows many limitations. In literature, it is reported that for brazed joints using ultrasonic testing, defect location can be identified by faster decay pattern of multiple echoes (compared to that of good location). In case of PM 2000 panel, reversal of the patterns is observed. This new phenomenon is verified with the support of PT. It is also found that for inconel panel, the decay patterns are as reported in literature.


2002 ◽  
Vol 6 (5-6) ◽  
pp. 284-290 ◽  
Author(s):  
Lourdes Ventolà ◽  
Teresa Calvet ◽  
Miquel Ángel Cuevas-Diarte ◽  
Valerie Métivaud ◽  
Denise Mondieig ◽  
...  

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