Title
Design and development of a shape memory alloy activated heat pipe-based thermal switch
Abbreviated Journal Title
Smart Mater. Struct.
Keywords
NEUTRON-DIFFRACTION; IN-SITU; R-PHASE; TRANSFORMATION; BEHAVIOR; NITI; TEMPERATURES; DEFORMATION; TI50NI47FE3; RECOVERY; Instruments & Instrumentation; Materials Science, Multidisciplinary
Abstract
This work reports on the design, fabrication and testing of a thermal switch wherein the open and closed states were actuated by shape memory alloy (SMA) elements while heat was transferred by a two-phase heat pipe. The motivation for such a switch comes from NASA's need for thermal management in advanced spaceport applications associated with future lunar and Mars missions. As the temperature can approximately vary between -233 and 127 degrees C during lunar day/night cycles, the switch was designed to reject heat from a cryogen tank into space during the night cycle while providing thermal isolation during the day cycle. A Ni47.1Ti49.6Fe3.3 (at.%) alloy that exhibited a reversible phase transformation between a trigonal R-phase and a cubic austenite phase was used as the sensing and actuating elements. Thermomechanical actuation, accomplished through an antagonistic spring system, resulted in strokes up to 7 mm against bias forces of up to 45 N. The actuation system was tested for more than thirty cycles, equivalent to one year of operation. The thermal performance, accomplished via a variable length, closed two-phase heat pipe, was evaluated, resulting in heat transfer rates of 13 W using pentane and 10 W using R-134a as working fluids. Experimental data were also compared to theoretical predictions where possible. Direct comparisons between different design approaches of SMA helical actuators, highlighting the effects of the helix angle, were carried out to give a layout of more accurate design methodologies.
Journal Title
Smart Materials and Structures
Volume
22
Issue/Number
10
Publication Date
1-1-2013
Document Type
Article
Language
English
First Page
17
WOS Identifier
ISSN
0964-1726
Recommended Citation
"Design and development of a shape memory alloy activated heat pipe-based thermal switch" (2013). Faculty Bibliography 2010s. 3693.
https://stars.library.ucf.edu/facultybib2010/3693
Comments
Authors: contact us about adding a copy of your work at STARS@ucf.edu