I have one question about the application of nano particle in PTC(parabolic through collector). I have prepared a mathematical model and MATLAB code about the simulation of PTC. I also validate the code with experimental data of other references for base fluid of water and the answers have a good agreement with those data. But I have encountered the strange phenomena. When I added nano-particle (AL2O3 OR CUO) to base fluid (water), although the heat convection coefficient is increased BUT the exit temperature will be decreased. So I have two questions:
1- This result is reasonable or not? I think that since adding the nano particle, increases the density of fluid so mass flow rate is increased and exit temperature in decreased. My idea is true or not? Also this result is opposite of paper attached.
2- I considered the density, viscosity and specific heat coefficient of nano fluid cosidering the weight function.
2- For the Nu regime I have used the Nu=0.023Re^0.8Pr^0.4 for both base and nano fluids. does it need a correlation or not? If yes and you know about the paper with correlation for (CUO AND AL2O3 AND WATER) please let me know about this.
Dear Mehdi,
Beside comapring with experimental data, you can use CFD tool from FLUENT to obtain a reliable behavior on how the temperature should vary with different nanofluids, as we did in our studies.
Best,
Mohammad
Dear Rasikh,
Of course the continuity of nanofluid is not as much as base fluid, but due to small nanoparticle sizes, it can be also considered a continuum fluid.
You need to write a UDF to model nanofluid using FLUENT, specifically to incorporate nanoparticles within the base fluid.
Hope it helps you.
Dear Mehdi
you may want to calculate thermo-physical properties of mixture using single phase relations for example Cp and Rho, then for a steady-state condition you can examine outlet temperature by employing Q=mdot.Cp.dt
it is important to clear if you are calculating for constant Reynolds or constant flow rate. finally for nanofluids you can employ modified dittus-boelter : Nu=0.025*Re^0.8*Pr^0.4
bests
Dear Milad
I calcuulate the properties of nano fluids but the temperature raise is about 2 centigrades.I am not sure about it.
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