In order to measure the thermal conductivity of nanofluids, different types of equipment are available including hot disk and laser flash apparatus (LFA). In literature, some researchers show that different measurement techniques give different values of thermal conductivity for the same sample and they differ significantly.
I wanted to ask what is the reason for this discrepancy and also is it possible to get repeatable values of thermal conductivity using different techniques like hot disk and LFA?
Numerous studies have been carried out in order to measure, but also to explain and predict, the increase in the thermal conductivity of nanofluids. Different methods for measuring thermal conductivity have been used, the most common being the method using a hot wire in a transient state. Nevertheless, given the dispersion of the results, experimental biases were suspected and other measurement methods were used, such as the 3ω method (deviation of 0.1%), stationary methods using a temperature difference between two plates or two cylinders and optical methods based on the variation of the refractive index as a function of temperature.
However, for your information, the LAMBDA, Flucon's thermal conductivity analyzer, is based on the hot wire technique. The device has been specially designed to measure the thermal conductivity and the thermal diffusivity of liquids from -50°C to 300°C, and at different pressures. The LAMBDA technique relies on a short test time of one second and a transient measurement approach in order to limit the effects of convection. This guarantees very precise measurements with excellent reproducibility. LAMBDA complies with the international standard ASTM D7896 – Standard Test Method for Thermal Conductivity, Thermal Diffusivity and Volumetric Heat Capacity of Engine Coolants and Related Fluids by Transient Hot Wire Liquid Thermal Conductivity Method.
Regards
Dear all, please have a look at the following reviews on the different techniques for measuring the thermal conductivity of nanofluids. My Regards
https://doi.org/10.1016/j.rser.2010.03.017
https://doi.org/10.1016/j.ijheatmasstransfer.2016.09.080
https://link.springer.com/article/10.1007/s10765-020-2621-2
https://doi.org/10.1063/1.2970086
https://doi.org/10.1021/acs.jced.6b00767
https://iopscience.iop.org/article/10.1088/1757-899X/226/1/012146
Dear Sir, Bachir Achour and Abdelkader BOUAZIZ thank you for your replies.
Dear Muhammad Shoaib Ijaz . See the following useful RG link: Article Techniques for measuring the thermal conductivity of nanoflu...
Kindly see also the following useful RG links: Article Experimental Measurements on the Thermal Conductivity of Gly...
Article Effective Thermal Conductivity of Nanofluids: Measurement an...
https://arxiv.org/pdf/1605.08469
Also check please the following useful RG link: Article Thermal conductivity measurements of nanofluids
The following RG link is also very useful: Article Measurement of thermal conductivity of nanofluids by the mul...
Visit also the following useful links: https://eprints.ucm.es/26461/1/Khayet50.pdf
https://researchrepository.ucd.ie/rest/bitstreams/40546/retrieve
https://iopscience.iop.org/article/10.1088/1742-6596/547/1/012046/pdf
Dear Professor, Aref Wazwaz thank you for sharing the journal papers.
You are most welcome dear
Prof. Muhammad Shoaib Ijaz
Wish you the best always
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