Project Details
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A new scientific device for the simultaneous determination of temperature dependent thermal properties: thermal diffusivity, heat conductivity and heat capacity

Subject Area Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials
Physical Chemistry of Solids and Surfaces, Material Characterisation
Term from 2017 to 2022
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 326948128
 
Final Report Year 2023

Final Report Abstract

In the project a new scientific device is developed that is capable of measuring the main thermal properties heat conductivity and thermal diffusivity within a single experimental cycle as a function of temperature. Principle of the method is to evaluate temperature distributions along a sample that is subjected to a steep temperature gradient in stationary and transient states. A cylindrical sample is heated at one side using induction heating and cooled at the other side using cooling water streaming in a laminar manner. A one dimensional heat flow through the sample is ensured using the at present best available thermal insulator (aerogel). The heat flow is quantified by measuring the temperatures in the cooling water in front of and behind the sample. The temperature distributions along the samples are measured optically with highest possible precision during heating, the stationary state and cooling using a modern infrared camera (phonon detector). The numerous temperature profiles recorded during heating and cooling are analyzed using a numerical inverse method that solves the heat equation and yields the temperature dependent thermal diffusivity. The stationary state is used to determine the temperature dependent heat conductivity by employing Fourier’s law. Employing the new method allows thermal characterization with the same accuracy as standard methods using two devices, but with a drastically reduced effort with respect to experimental time by up to two orders of magnitude. The reduced effort renders systematic studies of complex alloy systems possible.

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