Measuring Nanofluid Thermal Diffusivity and Thermal Effusivity: The Reliability of the Photopyroelectric Technique

Abstract

It is important to study nanofluids to understand their extraordinary thermal properties and how the size, concentration and agglomeration of the nanoparticles affect those properties. Photopyroelectric (PPE) technique has been well established in the use of non-destructive measurement of thermal diffusivity and thermal effusivity, by using polyvinylidene fluoride (PVDF) films as sensitive pyroelectric sensors in thermally thick conditions instead of using very thick ceramic sensors. There have been two proposed practical configurations for the PPE technique, the back and the front PPE configurations, to obtain both the thermal diffusivity and effusivity, which are suitable thermal parameters of materials. This PPE technique involves the measurement of thermal waves in the sample due to absorption of optical radiation, by placing a pyroelectric sensor in thermal contact with the sample. This chapter provides a review of the back and the front PPE configurations to determine the thermal diffusivity and effusivity of nanofluids, sample preparation techniques using high-amplitude ultrasonic dispersion and data analysis for metal oxide-based nanofluid materials.

Determination of the Thermal Diffusivity of Plasmonic Nanofluids Containing PVP-Coated Ag Nanoparticles Using Mode-Mismatched Dual-Beam Thermal Lens Technique

“…Besides the numerous studies employing techniques that allow direct access to the thermal conductivity and heat capacity of nanofluids, there are only a small number of studies that employ experimental techniques to directly obtain the thermal diffusivity of nanofluids. Some available methods and techniques are laser flash [7], hot-wire [8,9], photoacoustic [10][11][12], photopyroelectric [13], thermalwave resonator cavity [14], and the thermal lens technique [15]. The last one is based on the optical properties of a medium with optical absorption and has been employed previously to obtain the thermal diffusivity of colloids of superparamagnetic nanoparticles [16].…”

Evaluation of the dispersion properties of graphene oxide/cetyltrimethylammonium bromide for application in nanocomposite materials

“…[26][27][28][29][30] The BPPE technique has some advantages when compared with other existing methods such as the minimal sample volume required, the easy sample loading and removing, the relatively simple experimental set-up and measurement methodology, the maxim thermal contact that is achieved between the liquid sample and the pyroelectric sensor, and the short measurement times provided the concentration of the sample remains stable. 31 Modication of GO through self-assembly with the cationic surfactant cetyltrimethylammonium bromide (CTAB) depends on the hydrophobic interaction of the alkyl chains of the CTAB molecules and their functionalization on the surface of GO to prevent re-stacking and agglomeration of the exfoliated akes by a variety of conditions such as: the size of GO nanoparticles (GONPs) and CTAB, the mixing ratio, the state of dispersion/ aggregation, the effect of salt concentration, and osmotic stress. [32][33][34] The role of surfactant is to increase the dispersibility of GO sheets in suspensions due to van der Waals forces such as electrostatic or carbon-p interactions which can also contribute to binding.…”

“…The BPPE technique has some advantages when compared with other existing methods such as the minimal sample volume required, the easy sample loading and removing, the relatively simple experimental set-up and measurement methodology, the maxim thermal contact that is achieved between the liquid sample and the pyroelectric sensor, and the short measurement times provided the concentration of the sample remains stable. 31…”

Temperature Diffusivity Measurement and Nondestructive Testing Requiring No Extensive Sample Preparation and Using Stepwise Point Heating and IR Thermography

“…Among nonharmonic transient techniques of thermal stimulation, laser flash technique (LFT) proposed back in 1961 by Parker et al [41] is the most widely used up to date. It can be easily adopted for testing plate samples of homogeneous [42], anisotropic [43,44], porous [45], translucent [46] solids as well as liquids [47][48][49][50][51][52]. LFT is supported by commercially available equipment [53,54] operating according to established standards [55][56][57].…”