Self-consistent measurement of all thermal parameters of a liquid by FPPE-TWRC technique

The front photopyroelectric (FPPE) configuration, together with the thermal-wave resonator cavity (TWRC) method was applied in order to measure both thermal effusivity and diffusivity of liquids. The methodology is based on a 4-layer detection cell (pyroelectric sensor, coupling fluid, solid separator and liquid backing) in which the investigated liquid is inserted successively in backing and in coupling fluid's position, respectively. In such a way the FPPE-TWRC method becomes self-consistent; all static and dynamic thermal parameters can be derived with the same technique (two of them are directly measured and the remaining two calculated). The suitability of the method was demonstrated with investigations on several liquids as: ethylene glycol, glycerine, silicon and mineral oils.