Experimental study of non-boiling heat transfer from a horizontal surface by water sprays

Karwa, Nitin; Kale, S.R.; Subbarao, P.M.V.

doi:10.1016/j.expthermflusci.2007.06.007

Cited by 63 publications

(33 citation statements)

References 23 publications

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“…The position of the contact line is depicted by a purple line. From a first analysis, it can be observed that the heat transfer coefficient values evaluated according to the proposed formulation are in the same order of magnitude as those reported in the, literature by [2] and [3] for the sensible heat transfer removed by spray cooling. In the present investigation, a maximum heat transfer coefficient of 91,831 W/m 2 ·K was evaluated at t = 1 ms after the impact and at a radial distance r = 1840 µm.…”

Section: Relation Between Heat Tranfer and Droplet Dynamicssupporting

confidence: 54%

“…However efficient cooling can be obtained also relying only on the sensible heat removed from the droplet without the occurrence of phase change. Even in this case, heat transfer coefficients as high as 24,000 W/m 2 ·K [2] and up to 660,000 W/m 2 ·K [3] have been reported in literature, thus confirming that even without boiling, the sensible heat transfer during droplet impact is still suitable for cooling applications.…”

Section: Literature Reviewsupporting

confidence: 51%

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Sensible Heat Transfer during Droplet Cooling: Experimental and Numerical Analysis

et al. 2017

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This study presents the numerical reproduction of the entire surface temperature field resulting from a water droplet spreading on a heated surface, which is compared with experimental data. High-speed infrared thermography of the back side of the surface and high-speed images of the side view of the impinging droplet were used to infer on the solid surface temperature field and on droplet dynamics. Numerical reproduction of the phenomena was performed using OpenFOAM CFD toolbox. An enhanced volume of fluid (VOF) model was further modified for this purpose. The proposed modifications include the coupling of temperature fields between the fluid and the solid regions, to account for transient heat conduction within the solid. The results evidence an extremely good agreement between the temporal evolution of the measured and simulated spreading factors of the considered droplet impacts. The numerical and experimental dimensionless surface temperature profiles within the solid surface and along the droplet radius, were also in good agreement. Most of the differences were within the experimental measurements uncertainty. The numerical results allowed relating the solid surface temperature profiles with the fluid flow. During spreading, liquid recirculation within the rim, leads to the appearance of different regions of heat transfer that can be correlated with the vorticity field within the droplet.

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Section: Relation Between Heat Tranfer and Droplet Dynamicssupporting

confidence: 54%

Section: Literature Reviewsupporting

confidence: 51%

Sensible Heat Transfer during Droplet Cooling: Experimental and Numerical Analysis

et al. 2017

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“…A research performed by Karwa et al [28] in the year 2007 by spray cooling with the low wall superheats reported that the heat transfer takes place mainly using the single phase convection mechanism. When the saturation temperature of the fluid is equal to the heated surface temperature then there will be higher evaporation rates and there will be a formation of the thin film on the surface of the heating element.…”

Section: Chapter II Literature Reviewmentioning

confidence: 99%

Spray Cooling With HFC-134a and HFO-1234yf for Thermal Management of Automotive Power Electronics

Yaddanapudi

Bostanci

2015

Volume 8B: Heat Transfer and Thermal Engineering

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“…The droplets can diffuse on the surface to form the thin liquid film, removing large quantities of heat not only due to the latent heat of evaporation but also the substantial convection effects (Horace et al (2005), Bostanci et al (2018)). In fact, spray cooling technology has been demonstrated to be an attractive method that is adopted for some high heat flux applications to take heat flux away from heat surfaces with low droplet impact speed, low surface superheat and heat removal uniformity (Hsieh ShouShing et al (2015), Karwa et al (2007), Kim et al (2007), Xiao et al (2017)). Recently, spray cooling researchers have paid more attention to improving the performance of heat transfer by using enhanced surfaces, and various studies have been conducted.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of spray cooling performance with enhanced heating surface structures

Wang

Jiang

2018

JTST

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An open loop spray cooling experimental system with ten enhanced groove surfaces was established. The results show that maintaining an unchanged groove width and changing the groove depth from 0.2 mm to 1.6 mm, the surface with a groove depth of 0.8 mm, the largest heat flux enhancement appears when volume flow rate is 0.45 L/min and 0.75 L/min. However, the heat transfer performance increased with an increasing groove depth under the flow rate of 1.25 L/min. Then based on the analysis of the forces acting on the falling droplet, the residual velocity of the droplet is calculated to explain why the optimal heat transfer of enhanced surfaces is different at different volume flow rates. Maintaining a groove depth of 0.8 mm, as the groove bottom width was reduced from 4 mm to 1 mm, the heat transfer coefficient increased by 41%. With the spray flow rate of 1.25 L/min, the heat transfer coefficient increased by only 8.5% and the reason for this phenomenon is explained by the variation of Bond number which reflects the capillary force. Finally, a relevant correlation of the non-dimensional Nusselt number Nu for the grooved surface is proposed in the non-boiling area with water coolant.

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Experimental study of non-boiling heat transfer from a horizontal surface by water sprays

Cited by 63 publications

References 23 publications

Sensible Heat Transfer during Droplet Cooling: Experimental and Numerical Analysis

Sensible Heat Transfer during Droplet Cooling: Experimental and Numerical Analysis

Spray Cooling With HFC-134a and HFO-1234yf for Thermal Management of Automotive Power Electronics

Experimental investigation of spray cooling performance with enhanced heating surface structures

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