1.

Rusheet, SD. Application of Nanoparticle

Saturated Injectant Gases for EOR of Heavy

Oils, SPE, 2009;129539.

 2.

Shokrlu, YH, Babadagli, T. Effects of Nano

Sized Metals on Viscosity Reduction of Heavy

Oil/Bitumen during Thermal Applications,

CSUG/SPE, 2010;137540.

3.

Phys. Lett. A, 378,1845,2014

For an (extremely) viscous liquid, adding the right polymer can approximately speaking reduce the viscosity. The polymer apparently acts as a plasticizer on the liquid. The interesting work on this was done by Susan Amelar and (list of names). I am oversimplifying, a lo; I did not say 'zero-shear viscosity' here.t. There is a short discussion in my book Phenomenology of Polymer Solution Dynamics.  I am not quite answering your question. My intuition is that the particles would need to be quite small if they were compact..

Metal nanoparticles are used to reduce viscosity of heavy oils. Which is your liquid?

For the mineral nanoparticles that are added to the liquid; theoretically the answer is no. Addition those particles to the liquid increase the viscosity because of hydrodynamic motion of particle, particle-liquid interaction and particle-particle interaction.

I am also not quite answering your question, but a liquid soap (or dishwasher detergent) can do it; hence , maybe functionalized nanoparticles could also do it!

If your liquid and particles are water ( or liquid in similar viscosity range) and metals, theoretically and experimentally, for sure your answer is NO. However, for extremely viscous oily fluid it would happen, in some rare cases.  GoodLuck

which metal Mr. Mehta?   i need a reference

1.

Rusheet, SD. Application of Nanoparticle

Saturated Injectant Gases for EOR of Heavy

Oils, SPE, 2009;129539.

 2.

Shokrlu, YH, Babadagli, T. Effects of Nano

Sized Metals on Viscosity Reduction of Heavy

Oil/Bitumen during Thermal Applications,

CSUG/SPE, 2010;137540.

3.

Phys. Lett. A, 378,1845,2014

Generally, if you have a simple liquid, adding particles will increase the viscosity due to a larger distortion of the flow field and therefore higher dissipation.

Adding active particles (swimmers) can reduce the viscosity. This works because the swimmers inject more energy into the flow than they contribute to dissipation. This only works for a finite time until the swimmers run out of energy.

Another possibility may be to add bubbles with a very small internal viscosity, but I am not sure if this can actually decrease the overall apparent viscosity.

The important part of the Amelar -Lodge result is that the solvent is not just  a passive bystandarder whose properties are unaffected when you add things to it.  The Lodge experiments  -- it's all in my book Phenomenology of Polymer Solution Dynamics --show that the solvent, within several molecular diameters of whatever you have added to it -- can have dynamic properties that are quite different from the bulk, so adding nano-objects can lower the viscosity.  Simple example, very small nano-objects: Add to the solvent of interest another small-molecule liquid (very nano objects) that is miscible and in neat fluid form has a lower viscosity.

Dear Amir

You can find your answer which is the subject of the attached article. Based on a non-Newtonian model, it has been shown that the effective viscosity may be reduced by the nanoparticle addition for some volume fractions and for some shear rates.

Cheers

A tip of the hat to Dr. Aref for asking a clear simple question that generated a lot of very different answers.

thats kind of you, Dr. Phillies

There are two questions embedded here, in my opinion. 

The first question is: what type of fluid are we talking about?

If it is a simple molecular (newtonian) fluid, Einstein showed that you can only increase the true viscosity.

On the other hand, if you're talking about a non newtonian fluid, such as a polymeric liquids, non newtonian oils, etc... there is no reason why an additive my not change, even dramatically, the rheological properties of the fluid.

The second question is about the "viscosity". Which viscosity? Is it the true or apparent viscosity (e.g. brookfield viscosity)? at what shear rate/ shear stress?...

Depending on the answers to those questions, different answers can be given to the original question.

Einstein assumed that the added particles did not affect the bare properties of the solvent.  This result is now known, see above, to be incorrect on a molecular scale.

So? There is an approximation which does not mean it is incorrect, one just has to be aware of it.

Anyway, all this is moot as the original question was about the effect of Nps on the heat treatment of heavy oils...

there are a lot of experimental works all over the world that show the einstein equation cannot predict the rheological behaviour of nanofluids, even newtonian ones. i think there is a phenomena which play a significant role at very low concentrations which relates to the interactions between some nanoparticles and the host fluid. 

In polar fluids or magnetic suspensions there will be spin-spin interactions and hydrodynamics will be modified. This will also affect viscosity.

Viscosity in heavy oils is the result of high asphaltene content (10% or more). These asphaltenes form small aggregates (around 10 nm thick) which give the rheological behavior to the crude oil. When nanoparticles (NP) of silica or any other strong adsorbent are added to the oil, floculation of these aggregates around the NP will be promoted and this will change the rheology of your crude. Because now you have fewer and larger particles this could lead to a reduction in viscosity

You can check our newly published paper, and you can find an answer. Here we propose nanofluids that can reduce significantly the viscosity of a Newtonian host solvent.  

https://www.researchgate.net/publication/319006845_Self_-Propelled_Nanofluids_a_Path_to_a_highly_Effective_Coolant

Article Self –Propelled Nanofluids a Path to a highly Effective Coolant

Dear Dr Amer,

i think there is a phenomena which play a significant role at very low concentrations which relates to the interactions between some nanoparticles and the host fluid. 

this is a very interested idea