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Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment.

Ramesh G, Prabhu NK - Nanoscale Res Lett (2011)

Bottom Line: Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics.Further water-based nanofluids are environment friendly as compared to mineral oil quench media.These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Srinivasnagar, Mangalore, India. prabhukn_2002@yahoo.co.in.

ABSTRACT
The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment.

No MeSH data available.


Related in: MedlinePlus

Effect of alloying elements on TTT diagram.
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Figure 4: Effect of alloying elements on TTT diagram.

Mentions: It clears from the above study, the addition nanoparticles to the base fluids would result in a change in thermophysical properties of the base fluids. A wide spectrum of microstructure and mechanical properties can be obtained for a given steel component by controlling the cooling rate (Figure 3) [101]. In order to attain the fully quenched structure (martensitic structure), the component must be quenched below the nose of the TTT curve called critical cooling rate. This critical cooling rate is not a constant for all materials and addition of alloying elements to the steel shift the nose of TTT curve (Figure 4) [102]. Therefore, the heat treaters need different types of quenching media to provide varying critical cooling rate. Table 1 shows for the same base fluid, addition different nanoparticle materials at different concentrations yield varying thermal conductivities. Jagannath and Prabhu observed peak cooling rates varying from 76°C/s to 50.8°C/s by addition of Al2O3 nanoparticles of concentration 0.01 to 4% by weight into water during quenching of copper probe [103]. The standard cooling curve analysis by Gestwa and Przyłecka observed that addition 1% of Al2O3 nanoparticles to the 10% polymer water solution results cooling speed increases from 98 to 111°C/s [104]. Babu and Kumar also observed different cooling rates with the addition of different concentration of CNT into water during quenching of stainless steel probe [105]. Further, the addition of nanoparticles not only changes the peak cooling rate but also results in change of the six cooling curve characteristics. Hence, the change in thermophysical properties of base fluids with addition of nanoparticles can be utilized to prepare fluids having different cooling properties by controlling the particle volume concentration, particle material, particle size, particle shape and base fluid. Synthesis of quenching media having varying cooling severity would greatly benefit the heat treatment industry.


Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment.

Ramesh G, Prabhu NK - Nanoscale Res Lett (2011)

Effect of alloying elements on TTT diagram.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211422&req=5

Figure 4: Effect of alloying elements on TTT diagram.
Mentions: It clears from the above study, the addition nanoparticles to the base fluids would result in a change in thermophysical properties of the base fluids. A wide spectrum of microstructure and mechanical properties can be obtained for a given steel component by controlling the cooling rate (Figure 3) [101]. In order to attain the fully quenched structure (martensitic structure), the component must be quenched below the nose of the TTT curve called critical cooling rate. This critical cooling rate is not a constant for all materials and addition of alloying elements to the steel shift the nose of TTT curve (Figure 4) [102]. Therefore, the heat treaters need different types of quenching media to provide varying critical cooling rate. Table 1 shows for the same base fluid, addition different nanoparticle materials at different concentrations yield varying thermal conductivities. Jagannath and Prabhu observed peak cooling rates varying from 76°C/s to 50.8°C/s by addition of Al2O3 nanoparticles of concentration 0.01 to 4% by weight into water during quenching of copper probe [103]. The standard cooling curve analysis by Gestwa and Przyłecka observed that addition 1% of Al2O3 nanoparticles to the 10% polymer water solution results cooling speed increases from 98 to 111°C/s [104]. Babu and Kumar also observed different cooling rates with the addition of different concentration of CNT into water during quenching of stainless steel probe [105]. Further, the addition of nanoparticles not only changes the peak cooling rate but also results in change of the six cooling curve characteristics. Hence, the change in thermophysical properties of base fluids with addition of nanoparticles can be utilized to prepare fluids having different cooling properties by controlling the particle volume concentration, particle material, particle size, particle shape and base fluid. Synthesis of quenching media having varying cooling severity would greatly benefit the heat treatment industry.

Bottom Line: Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics.Further water-based nanofluids are environment friendly as compared to mineral oil quench media.These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Srinivasnagar, Mangalore, India. prabhukn_2002@yahoo.co.in.

ABSTRACT
The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment.

No MeSH data available.


Related in: MedlinePlus