Design and Modeling of a Radiator with Digital Turn-Down Capability under Variable Heat Rejection Requirements

Miller, Jennifer R.; Birur, Gajanana C.; Ganapathi, Gani B.; Sunada, Eric; Berisford, D. F.; Stephan, Ryan A.

doi:10.2514/6.2011-5002

Cited by 5 publications

(3 citation statements)

References 2 publications

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“…tubes, according to the full scale digital radiator design. 8,9 Figure 11 shows the experimental setup. Manual valves are denoted V1, V2, etc., and heaters are denoted H1, etc.…”

Section: B Smooth-wall Tube Experimentsmentioning

confidence: 99%

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Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

Berisford

Birur

Miller

et al. 2011

41st International Conference on Environmental Systems

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“…tubes, according to the full scale digital radiator design. 8,9 Figure 11 shows the experimental setup. Manual valves are denoted V1, V2, etc., and heaters are denoted H1, etc.…”

Section: B Smooth-wall Tube Experimentsmentioning

confidence: 99%

“…Digital radiator technology is one of several promising emerging concepts currently under development to deliver a lightweight single-loop solution to meet the rigorous demands of human spaceflight missions [7][8][9] . The basic concept, shown schematically in Fig.…”

Section: Introductionmentioning

confidence: 99%

Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

Berisford

Birur

Miller

et al. 2011

41st International Conference on Environmental Systems

Self Cite

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“…[7][8][9][10][11][12] In addition, complex systems have been introduced in order to handle the transient environments and the heat loads using digital turn-down radiators for low lunar orbits. 13 Moreover, shape memory alloys (SMAs) play a primary role in the development of systems capable of handling the thermal radiation. Reversible thermal panel (RTP) radiators alter their function from a radiator to a solar absorber in order to save power.…”

Section: Introductionmentioning

confidence: 99%

Preliminary design and comparative study of thermal control in a nanosatellite through smart variable emissivity surfaces

Αθανασόπουλος

Farmasonis

Siakavellas

2018

Proceedings of the Institution of Mechanical Engineers, Part G:

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The thermal radiation that is rejected or absorbed into deep space is highly variable. Ultralight smart surfaces with arrays of unit cells can be designed to change their effective emissivity and absorptivity without energy consumption, actuators, and controllers, and can be used for the temperature control of satellites. The smart surfaces work in a similar manner to thermal louvers but they are hingeless, lighter, and their activation depends on their anisotropic mechanical properties and multilayer structure. The generated thermal stresses between layers that have a high mismatch in the coefficient of thermal expansion cause large deformations and rotations within small temperature changes. The arrays of the surface open or close, and transform their geometry as a function of temperature; therefore, coatings of different thermo-optical properties are revealed or concealed, thus creating variable emissivity surfaces. The emissivity and absorptivity curves of the smart surfaces can be entirely designed as a function of temperature. Theoretically, an emissivity change equal to Δε = 0.8 can be achieved. The small thermal capacitance renders nanosatellites very susceptible to temperature fluctuations. In this study, different emissivity curves were generated to re-calculate the worst cold and hot cases, and to redesign the thermal control system of a certain nanosatellite. We studied a plethora of design cases based on the energy balance equation in steady state while considering the nanosatellite as one-node geometry. In two ideal designs, the temperature deviation of the nanosatellite in the worst cold and hot cases is limited to Δ Τ = 37 ℃ or 43 ℃ without the use of heaters. Moreover, with a power equal to 0.7 W the temperature deviation is limited to Δ Τ = 20 ℃. Consequently, the thermal fatigue is minimized and the energy consumption during the eclipse phase is reduced.

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Compact Heat Rejection System Utilizing Integral Variable Conductance Planar Heat Pipe Radiator for Space Application

Lee

Guzek

et al. 2015

Gravitational and Space Research

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In order to meet heat rejection requirements for future NASA exploration, scientific, and discovery missions, a study is being conducted for the feasibility of integral variable conductance planar heat pipe (VCPHP) technology. This represents a novel, low technology readiness level (TRL) heat rejection technology that, when developed, could operate efficiently and reliably across a wide range of thermal environments. The concept consists of a planar heat pipe whose evaporator acquires the excess thermal energy from the thermal control system and rejects it at its condenser whose outer surface acts as a radiating surface. The heat pipe is made from thermally conductive polymers in order to minimize its mass. It has a non-condensable gas that changes the active radiator surface depending on the heat load. A mathematical model of steady-state variable conductance heat pipe is developed. Two planar heat pipes are designed, fabricated, and tested to validate the theoretical model. The feasibility of the proposed VCPHP working in a space environment is discussed, based on the model.

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Design and Modeling of a Radiator with Digital Turn-Down Capability under Variable Heat Rejection Requirements

Cited by 5 publications

References 2 publications

Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

Preliminary design and comparative study of thermal control in a nanosatellite through smart variable emissivity surfaces

Compact Heat Rejection System Utilizing Integral Variable Conductance Planar Heat Pipe Radiator for Space Application

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