Development of a Smart Material Integrated Sensor Thermal Switch for Thermal Management

In this work, advanced materials technology is employed to design a thermal switch that has integrated temperature sensing and the actuation of the switching device in tandem. The design involves the coupling of a variable area aluminum thermal sink with a Ni-Ti shape memory alloy (SMA) sensor to form an Autonomous Shape Memory Alloy Thermal Switch (ASMATS). The fabricated ASMATS is discussed in this article along with experiments conducted to ascertain its performance. In the experiments performed, the ASMATS is mounted in the common bulkhead of two fluid reservoirs maintained at different temperatures. The temperature in the lower reservoir was increased with a heater while that of the upper tank was maintained at a constant temperature. The rate of cooling from the lower reservoir was measured with and without the fin and a conclusive result was obtained on the effectiveness of the designed ASMATS. In addition, the transient natural convection heat transfer problem that results in the lower reservoir with the upper reservoir serving as a constant temperature heat sink is modeled and solved numerically. The simulation results are compared with experimental performance of the ASMATS.