Detailseite
Projekt
Development and Validation of a NiTi-Based Ferroelastic Cooling Demonstrator
Antragsteller
Professor Dr. Andreas Schütze
Fachliche Zuordnung
Herstellung und Eigenschaften von Funktionsmaterialien
Förderung
Förderung von 2012 bis 2015
Projektkennung
Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 226970786
In the last decades, alternative refrigeration methods have increasingly received attention because of their high efficiencies, which enable a more efficient use of resources and lower greenhouse gas emissions. Apart from the well-known attractive structural and mechanical properties, pseudoelastic NiTi-based shape memory alloys (SMAs) also exhibit promising caloric properties. These properties have generated a strong interest in NiTi alloys as potential solid state cooling material for novel ferroic cooling technologies. During a mechanical loading/unloading cycle, pseudoelastic NiTi-SMAs undergo stress induced, first order phase transitions between the austenitic and martensitic configuration. These phase transitions are associated with emission and absorption of extremely large latent heats (approx. 25kJ/kg), thus making this process generally suitable for novel cooling applications. The cooling efficiency of these processes not only depends on the basic material properties, which will be studied in a parallel project at the Ruhr-Universität Bochum, but especially on the technical realization of the cooling system. This aspect will be studied in the framework of this joint project proposal via development of a NiTi-based ferroelastic cooling demonstrator. In the first phase, this demonstrator will be designed as a scientific testing platform for gaining a fundamental physical understanding of the cooling process. This platform will allow controlled measurement of the transferred heats and the mechanical energy input for the determination of the relevant cooling efficiency. Furthermore, transient temperature fields will be precisely measured both on the hot and cold side heat sinks as well as on the employed NiTi cooling medium using a high speed, high resolution thermal imaging system. Combination with an optical camera system for measurement of the mechanical deformation fields will allow elucidation and characterization of the thermo-mechanically coupled processes associated with the rate dependent inhomogeneous phase transitions. This set-up will therefore allow characterization of different test samples from the Bochum group under realistic boundary conditions with various sample geometries, operating frequencies, heat transfer contacts etc. At the same time, the measurements will be used to validate a multi-field FE model for the thermo-mechanical simulation of NiTi cooling systems, which will be developed in a second parallel SPP project.
DFG-Verfahren
Schwerpunktprogramme
Beteiligte Person
Professor Dr.-Ing. Stefan Seelecke
