Semi-automatic non-commercial instrument for determining the thermal conductivity

0557207 - ÚT 2023 RIV CZ eng L - Prototyp, funkční vzorek
Hrubý, Jan - Kordík, Jozef - Nikl, Zbyněk
Semi-automatic non-commercial instrument for determining the thermal conductivity.
Interní kód: INV22-052 ; 2022
Technické parametry: rozsah teplot měřené kapaliny: 20 - 60°C, max. tlak v zařízení: 2 bar
Ekonomické parametry: Zařízení umožňuje měřit tepelnou vodivost kapalin bez některých parazitních jevů, které se vyskytují u standardních metod (usazování, termoforéza).
Grant CEP: GA TA ČR(CZ) TH03020313
Institucionální podpora: RVO:61388998
Klíčová slova: thermal conductivity * the Nusselt number * heat transfer coefficient
Obor OECD: Thermodynamics

The subject of the functional sample is a device serving for measurement of thermal conductivity of liquids. A tested liquid flows through the device, whose measuring part is formed by a bundle of parallel circular channels. The liquid flows through the channels at flow rate, that is chosen so that a laminar regime is achieved in each channel. A known amount of heat flux is being added to the liquid along a certain sector of the channel bundle. Since the heat transfer parameters for laminar circular flow are exactly known, the thermal conductivity of the tested liquid can be evaluated from the measured flow rate, added heat flux, and temperature differences.
This method is specifically suitable for liquids containing some particles. As the measured liquid is in continuous motion during the measurement, the sedimentation of particles and other phenomena such as thermophoresis (particle motion due to temperature gradients), which are problematic with the static methods, are avoided.
All process parameters are recorded and controlled by a computer with inhouse developed software. Consequently, the measuring procedure can be automated, with exception of cleaning, filling and similar operations.
Trvalý link: http://hdl.handle.net/11104/0332299