The performance of heat exchanger can be substantially improved by a number of augmentation techniques. One of these methods is Nanotechnology. Nanofluid widely used to enhance Nusselt number because of increase in thermal conductivity, at the same time the pressure drop increases as a result of an increase in viscosity of the new fluid. In order to quantify the overall thermal performance of the system that used Nanofluid, any criteria on how to evaluate the thermal–hydraulic performance used for this system ?
Thank you
Dear Haydar,
Irrespective of type of enhancement methods, and depending on objective function, one can define many criteria. The most common one is based on goodnees factor. Please read the "Principle of enhanced heat transfer, 2nd edition" written by Prof. Ralph. Webb.
Wish you all the best,
Hamidreza Rastan
The thermal performance is evaluated using Colburn factor and hydraulic performance (Pressure drop) using Fanning friction factor.
The thermal hydraulic performance of nanofluids are evaluated in the literature using the Thermal-hydraulic performance factor (JF).
Read the Paper:
Experimental analysis of thermal–hydraulic performance of
copper–water nanofluid flow in different plate-fin channels
by
M. Khoshvaght-Aliabadi , F. Hormozi , A. Zamzamian
Dear Dr. Hayder,
As we know using nanofluids as passive method to enhance heat transfer performance could be a good idea but also increasing drop of pressure due to high viscosity could be a challenge So, to evaluate that, A performance evaluation criterion (PEC) based on the same pumping power consumption is widely used to evaluate heat transfer enhancement using nanofluids as a working fluids with increased pressure drop. bellow the formula that be used in literature:
My regards
I think if we have best theoretical models for thermal conductivity and viscosity we can use equations which are applicable to basefluid.
I agree with (PEC) equation because it has been used for basefluid.
Viscosity of nanofluid
https://en.wikipedia.org/wiki/Viscosity#Viscosity_of_nanofluids
Thermal conductivity of nanofluid
https://en.wikipedia.org/wiki/Nanofluids_in_solar_collectors#Thermal_conductivity_of_nanofluids
Hope this would help you
Please read this paper. I think it will answer your question practically
https://www.sciencedirect.com/science/article/pii/S0307904X16300270
Dear Hamidreza, Navaneethakrishnan, Mohammed , Dilan and Amar
I appreciate your comments.
Thank you very much.
Regards
Hello, we are measuring the behaviour of a nanofluid in a real system, and over the theoretical method, we are checking before and after, preasure, temperature, fouling, overthemp alarms in the system, and then, density, wind speed and all other systems themperature, after the test we will check as well all the pipes cleanness and chekc with the previous condition.
Dear Francisco Garcia Lopez ,
Could you plz tell us about the application? I would like to know industry.
we are using as a trial test, in the converter cooler, in a Wind Turbine Generator, 2 MW, the mother fluid is water-glycol, in a fix comercial moisture, that we add nanoaditives. Historically speaking we use to have in the wind industry some problems with the temperature in some periods of the year. since is not worth to over dimensionate the coolers just for some days...but the reality is that we may loose some amount of production due to thermal problems, that we can solve without change anything just adding the particles and due that increase the heat exchange.
the commercial moisture is Havoline, I add the file, sorry is in spanish, but with the reference you can easy get the MSDS in english with the formulation, componets etc.
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