there is a general perception that if the base fluid is newtonian then the nanofluid is also newtonian but if the base fluid is non-newtonian then the nanofluid will be non-newtonian as well.
Is this true?
Dear Vipin
I do not know if you got your answer meanwhile. However, what you mentioned is true for very dilute cases. I mean, if the volume fraction of the nanoparticles increases, even if the base fluid was Newtonian, the resultant nanofluid may change to non-Newtonian. This depend on the base fluid, nanoparticles and the interaction between them (I mean at what volume fraction starts to change the behavior)
Regards,
Mohsen
Dear Vipin
I do not know if you got your answer meanwhile. However, what you mentioned is true for very dilute cases. I mean, if the volume fraction of the nanoparticles increases, even if the base fluid was Newtonian, the resultant nanofluid may change to non-Newtonian. This depend on the base fluid, nanoparticles and the interaction between them (I mean at what volume fraction starts to change the behavior)
Regards,
Mohsen
Thank you Prof. Mohsen for your reply.
But,in majority of nanofluid applications , the particle loading is very small as compared to the fluid concentration.So this rules out the change from newtonian to non newtonian behaviour due to particle concentration. Doesn't it? So, can you think of any other reason behind the deviation of these fluids from newtonian behaviour.
Thank you
Dear Vipin,
Actually,I am talking about the volume fractions up to 5% (usual nanofluids range) which we tested in our Lab. In our laboratory, even we found a nanoparticle which it changed the water as viscous as honey when using less than 2% volume fraction. We are thinking if it has the capability to receive a patent on it.
Regards,
Mohsen
Dear Vipin,
it depends on nanoparticle type, size and shape. For example in ethylene glycol: suspension of BN nanoplates, or Fe2O3 is strongly non-Newtonian, and Y3Al5O12, or ZnO nanoparticles suspension present Newtonian nature.
These processes are not yet exactly known, therefore it seems to me at the moment impossible to answer whether a suspension of nanoparticles in Newtonian liquids will lead to changing the nature to non-Newtonian liquid. Existing theoretical models not yet well describe this phenomenon, so I think you should measure rheological properties before use specific nanofluid.
Regards,
Gaweł
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