scholarly journals The Active Effect of Electric Field on Heat Transfer Enhancement for Spray Cooling

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Haojie Xu ◽  
Junfeng Wang ◽  
Dongbao Wang ◽  
Wei Zhang ◽  
Jiang Yao
2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Jian-nan Chen ◽  
Rui-na Xu ◽  
Zhen Zhang ◽  
Xue Chen ◽  
Xiao-long Ouyang ◽  
...  

Enhancing spray cooling with surface structures is a common, effective approach for high heat flux thermal management to guarantee the reliability of many high-power, high-speed electronics and to improve the efficiency of new energy systems. However, the fundamental heat transfer enhancement mechanisms are not well understood especially for nanostructures. Here, we fabricated six groups of nanowire arrayed surfaces with various structures and sizes that show for the first time how these nanostructures enhance the spray cooling by improving the surface wettability and the liquid transport to quickly rewet the surface and avoid dry out. These insights into the nanostructure spray cooling heat transfer enhancement mechanisms are combined with microstructure heat transfer mechanism in integrated microstructure and nanostructure hybrid surface that further enhances the spray cooling heat transfer.


Author(s):  
Koorosh Goudarzi ◽  
H. Jamali ◽  
V. Kalaei

In this experimental study, Aluminums Oxide (Al2O3) in Pure Water (PW) as nanofluid was used for heat transfer enhancement in car radiator together with electric field. Electric field with different voltage 8, 11, 14 kV and nanofluids with volume concentrations of 0.08%, 0.5% and 1% were investigated. From the experiments, it was found that the unit with electric field pronounced better heat transfer rate, especially at low fan speed. In addition heat transfer coefficient and heat transfer rate in engine cooling system increased with the usage of nanofluids Al2O3/PW compared to Pure Water alone. With the use of nanofluid with concentration of 1% and electric field for fan speed 600 and 1200 rpm, thermal performance factors were in a range between, 1.8–3.2 and 1.6–1.74, respectively. Thermal performance factor is more than 1 in all of cases, and it can be concluded that this technique can be used in car radiators to improve heat transfer.


Author(s):  
F. C. Lai ◽  
J. Mathew

Prior numerical solutions of electrohydrodynamic (EHD) gas flows in a horizontal channel with a positive-corona discharged wire have revealed the existence of steady-periodic flows. It is speculated that heat transfer by forced convection may be greatly enhanced by taking advantage of this oscillatory flow phenomenon induced by electric field. To verify this speculation, computations have been performed for flows with Reynolds numbers varying from 0 to 4800 and the dimensionless EHD number (which signifies the effect of electric field) ranging from 0.06 to ∞. The results show that heat transfer enhancement increases with the applied voltage. For a given electric field, oscillation in the flow and temperature fields occurs at small Reynolds numbers. Due to the presence of oscillatory secondary flows, there is a significant enhancement in heat transfer.


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