EFFECTS OF A RADIATION SYSTEM AND A WRAPPING METHOD OF MULTILAYER INSULATION ON HEAT TRANSFER IN CRYOGENIC SYSTEMS

Multilayer Insulation (MLI) blankets consist of closely spaced aluminum coated shields that are spaced apart to reduce heat transfer between the payload and the environment, particularly in vacuum. In space application, satellite systems and sub-systems are wrapped in MLI blankets to thermally isolate them from the environment and achieve thermal control requirements. During spacecraft launch, the payload undergoes a rapid depressurization before reaching steady state condition. The MLI blankets are usually perforated and/or connected at the boundaries with Velcro strips to allow out-gassing. The blankets can lose their integrity and functionality if the depressurization process is too rapid: the out-gassing flow can tear the perforations, and the pressure differential built-up across the blanket can pull the Velcro strips apart. This paper describes the design and modeling of depressurization through X-slits cut into the blanket and Velcro strips taped along the sides. A methodology is developed, and a model for quantifying the pressure differential build-up is described and applied to a payload enclosure aboard a Delta II rocket.

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The effect of plastic film transmittance on heat transfer in a multilayer insulation structure of rectangular air cells for frozen food wrapping

International Journal of Refrigeration ◽

10.1016/j.ijrefrig.2018.05.037 ◽

2018 ◽

Vol 92 ◽

pp. 94-105 ◽

Cited By ~ 3

Author(s):

Jacek Kasperski ◽

Beata Grabowska

Keyword(s):

Heat Transfer ◽

Plastic Film ◽

Frozen Food ◽

Multilayer Insulation ◽

Air Cells

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Spacer effects on lateral heat transfer in multilayer insulation

10.2514/6.1970-849 ◽

1970 ◽

Cited By ~ 3

Author(s):

P. JAGANNATHAN ◽

C. TIEN

Keyword(s):

Heat Transfer ◽

Multilayer Insulation ◽

Lateral Heat

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HEAT TRANSFER INVESTIGATION FOR A MULTILAYER INSULATION SYSTEM VIA RADIATIVE-CONDUCTIVE APPROACH UNDER LOW TEMPERATURE CONDITIONS IN SPACE

Revista de Engenharia Térmica ◽

10.5380/reterm.v19i2.78624 ◽

2020 ◽

Vol 19 (2) ◽

pp. 70

Author(s):

G. N. Lacerda ◽

M. F. Curi

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Temperature Field ◽

Insulation System ◽

Final Temperature ◽

Space Applications ◽

Conduction Heat Transfer ◽

Stationary Temperature Field ◽

Layer Density ◽

Multilayer Insulation

Thermal insulation is an important area, not restricted to mechanical engineering, but widely studied in environmentalissues, such as global warming and, above all, energy-saving, since controlling the heat flux on microprocessorsthrough temperature control on components in space applications. This work focuses on controlling the temperature incomponents that could not lose or gain so much heat in space, especiallywhen the overall safety of sending satellites onspecific missions is required. To ensure that, Multilayer Insulation (MLI) is used. With fluid mechanics and radiation-conductionheat transfer theory, it was possible to calculate the transient and stationary temperature field and heat flux inMLI. The boundary temperatures are specified at 300K and 4K. The results, from solving the resulting discretized ODE,simulated with fsolve and odeintScipy subroutines in Python, able to solve the equations numerically, were shown. Thedata given by the simulation was able to indicate the impacts of varying the layer density, emissivity of screen, the distancebetween screens and the perforation coefficient in stationary and transient approaches. A way to simulate the performanceof MLI numerically was presented. Modifying emissivity (e) showed variations higher than in the perforation coefficient(ξ). Layer density controls the distance between layers (d ), changing the conduction heat transfer. In the transient casesimulation, it was possible to notice that varying parameters impact in time to reach steady-state and final temperature.

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