Session: K6-08: HEAT TRANSFER IN ENERGY SYSTEMS - WASTE HEAT I

Paper Number: 131111

131111 - The Variation of Radiative Heat Loss As a Function of Actuation Angle for an Isothermal Square Twist Origami Radiator 

Abstract: 

Origami-inspired dynamic spacecraft radiators provide the ability for spacecraft to reject adjustable quantities of heat due to account for orbital variations in onboard heating. These radiators might also find utility for Lunar applications, where more extreme temperature variations complicate the rejection of heat from Lunar power plants. The square twist origami tessellation provides large increases in rejecting surface area as the tessellation is actuated from fully closed to fully deployed. However, the variation of radiative heat loss as a function of actuation position is not found in the literature. This study determines the radiative heat loss behavior of an isothermal square twist origami radiator as a function of actuation position. The geometric location of a square twist origami tessellation panels are modeled using vector algebra for an infinitely thin (2D) square twist tessellation as well as a “thick origami” (3D) rigidly-foldable tessellation, both characterized by an adjustable closure angle.

 

The heat loss characteristics of both the 2D and 3D square twist origami radiators over a 180-degree range of actuation angle have been calculated. Monte Carlo Ray Tracing was used to simulate the radiative losses from the 2D surface over a range of emissivity values (0.1 ,0.5, 1.0) and diffuse ray directions. The 3D surface was modeled with a radiosity balance implemented in the ANSYS thermal modeling environment.

Results show a divergence between the 2D and 3D square twist origami radiators. At an emissivity of 1, the ratio of escaped to emitted rays showcases distinct behavior. The 3D square twist origami radiator demonstrates a slower decrease in this ratio as the closure angle increases, culminating at a ratio of 0.4 at an actuation angle of 180 degrees. Conversely, the 2D square twist origami radiator exhibits a linear decline, reaching a ratio of 0.32 at an angle of 180 degrees. Thermal simulations across the range of motion with uniform surface temperatures showcase a turndown ratio (largest to smallest heat transfer) of 4.42. These results substantiate the practicality and efficacy of the rigidly foldable square twist model for radiative heat loss control.

The non-rigidly foldable geometry initially existed as a theoretical, infinitely thin sheet, but 3D realization with offset modeling in SolidWorks was achieved. A physical model, produced through 3D printing and tape hinges, demonstrated smooth folding, despite modeling intricacies. The thermal simulations in Ansys, under controlled conditions, quantified radiative heat loss trends at different fold angles. In contrast, the rigidly foldable square twist model, underwent a sophisticated offset panel technique to increase 3D height while maintaining flat folded configurations. This approach, combined with 3D printing and idealized hinges, resulted in a physical prototype capable of full actuation.

Further analysis extends to derivative geometries, including the "StarTwist," "SlopedSquareTwist," "OctaTwist," and "SquareTwistSmallSquare." While no 3D models were created for these variations, ray tracer simulations were conducted, adhering to the same range of emissivities. The results showcase the potential of these derivative geometries as promising contenders for advanced thermal management systems. Results demonstrate the efficient thermal management capable with origami radiators for space exploration, with origami-based designs offering adaptable surface area and dynamic thermal control capabilities. These initial insights underscore the merits of origami-based design, with the potential for further optimization and enhanced thermal efficiency. This research illuminates a path towards enabling dynamic heat rejection in future space missions, powered by origami radiator technology.

Presenting Author: Rydge Mulford University of Dayton

Presenting Author Biography: Dr. Rydge Mulford is an assistant professor at the University of Dayton

Authors:

Mohammed Farhan Aziz Najeeb University of Dayton
Jeremy Price University of Dayton
David Warburton University of Dayton
Rydge Mulford University of Dayton