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Spray cooling characteristics of nanofluids for electronic power devices.

Hsieh SS, Leu HY, Liu HH - Nanoscale Res Lett (2015)

Bottom Line: The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein.The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm.The heat transfer removal rate can reach up to 274 W/cm(2) with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9 × 10(-4) kg/cm(2)s.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Electromechanical Engineering, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan.

ABSTRACT
The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein. The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm. The effects of nanoparticle volume fraction and mass flow rate of the liquid on the surface heat flux, including critical heat flux (CHF), are explored. Both steady state and transient data are collected for the two-phase heat transfer coefficient, boiling curve/ cooling history, and the corresponding CHF. The heat transfer removal rate can reach up to 274 W/cm(2) with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9 × 10(-4) kg/cm(2)s.

No MeSH data available.


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Steady state boiling curve: (a) DI water, (b) nanofluids (Ag/MCNT).
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Fig7: Steady state boiling curve: (a) DI water, (b) nanofluids (Ag/MCNT).

Mentions: DI water at 25°C was sprayed onto a heated surface at varying pressures and flow rates. The heat flux and wall superheat were determined simultaneously as the wall surface was gradually heated. Figure 7a shows the heat transfer characteristics for G = 6.57 × 10−4, 8.92 × 10−4, and 11.9 × 10−4 kg/cm2s. There seems to be two distinct regions in the curves shown in Figure 7a, as also reported by Hsieh et al. [23]. In the first region, single-phase forced convection and evaporation are the modes of heat transfer. As the heat flux increased gradually, the slope of the curve changed, at which point nucleate boiling began. The heat flux kept increasing until the CHF was observed. From Figure 7a, drawn between wall superheat and the heat flux, it is observed that the boiling curves for DI water shifts towards the left, indicating that the wall superheat decreases with increasing mass flux, with a corresponding CHF increase; 118.8 W/cm2 at G = 11.9 × 10−4 kg/cm2s, 98.2 W/cm2 at G = 8.92 × 10−4 kg/cm2s, and 72.3 W/cm2 at G = 6.57 × 10−4 kg/cm2s, respectively.Figure 7


Spray cooling characteristics of nanofluids for electronic power devices.

Hsieh SS, Leu HY, Liu HH - Nanoscale Res Lett (2015)

Steady state boiling curve: (a) DI water, (b) nanofluids (Ag/MCNT).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385298&req=5

Fig7: Steady state boiling curve: (a) DI water, (b) nanofluids (Ag/MCNT).
Mentions: DI water at 25°C was sprayed onto a heated surface at varying pressures and flow rates. The heat flux and wall superheat were determined simultaneously as the wall surface was gradually heated. Figure 7a shows the heat transfer characteristics for G = 6.57 × 10−4, 8.92 × 10−4, and 11.9 × 10−4 kg/cm2s. There seems to be two distinct regions in the curves shown in Figure 7a, as also reported by Hsieh et al. [23]. In the first region, single-phase forced convection and evaporation are the modes of heat transfer. As the heat flux increased gradually, the slope of the curve changed, at which point nucleate boiling began. The heat flux kept increasing until the CHF was observed. From Figure 7a, drawn between wall superheat and the heat flux, it is observed that the boiling curves for DI water shifts towards the left, indicating that the wall superheat decreases with increasing mass flux, with a corresponding CHF increase; 118.8 W/cm2 at G = 11.9 × 10−4 kg/cm2s, 98.2 W/cm2 at G = 8.92 × 10−4 kg/cm2s, and 72.3 W/cm2 at G = 6.57 × 10−4 kg/cm2s, respectively.Figure 7

Bottom Line: The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein.The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm.The heat transfer removal rate can reach up to 274 W/cm(2) with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9 × 10(-4) kg/cm(2)s.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Electromechanical Engineering, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan.

ABSTRACT
The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein. The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm. The effects of nanoparticle volume fraction and mass flow rate of the liquid on the surface heat flux, including critical heat flux (CHF), are explored. Both steady state and transient data are collected for the two-phase heat transfer coefficient, boiling curve/ cooling history, and the corresponding CHF. The heat transfer removal rate can reach up to 274 W/cm(2) with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9 × 10(-4) kg/cm(2)s.

No MeSH data available.


Related in: MedlinePlus