Numerical and experimental investigation of heat transfer on heating surface during subcooled boiling flow of liquid nitrogen

Vibration characteristics of subcooled boiling flow on thin and long structures such as a heating rod were recently investigated by the authors. The results show that the intensity of the subcooled boiling-induced vibration (SBIV) was influenced strongly by the conditions of subcooling temperature, linear power density and flow velocity. Implosive bubble formation and collapse are the main nature of subcooled boiling, and their behavior are the only sources to originate SBIV. Therefore, in order to explain the phenomenon of SBIV, it is essential to obtain reliable information about bubble behavior in subcooled boiling conditions. This was investigated at different conditions of coolant subcooling temperatures of 25 to 75°C, coolant flow velocities of 16 to 53 cm/s, and linear power densities of 100 to 600 W/cm. High speed photography at 13,500 frames per second was performed at these conditions. The results show that even at the highest subcooling condition, the absolute majority of bubbles collapse very close to the surface after detaching from the heating surface. Based on these observations, a simple model of surface tension and momentum change is introduced to offer a rough quantitative estimate of the force exerted on the heating surface. The formation of a typical bubble in subcooled boiling is predicted to exert an excitation force in the order of 10−4 N.

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Experimental investigation of variability in bubble departure characteristics between nucleation sites in subcooled boiling flow

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2017.10.116 ◽

2018 ◽

Vol 118 ◽

pp. 327-339 ◽

Cited By ~ 9

Author(s):

Zhiee Jhia Ooi ◽

Vineet Kumar ◽

Joseph L. Bottini ◽

Caleb S. Brooks

Keyword(s):

Experimental Investigation ◽

Subcooled Boiling ◽

Nucleation Sites ◽

Boiling Flow

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Numerical Prediction for Subcooled Boiling Flow of Liquid Nitrogen in a Vertical Tube with MUSIG Model

Chinese Journal of Chemical Engineering ◽

10.1016/s1004-9541(13)60632-1 ◽

2013 ◽

Vol 21 (11) ◽

pp. 1195-1205 ◽

Cited By ~ 3

Author(s):

Simin WANG ◽

Jian WEN ◽

Yamei LI ◽

Huizhu YANG ◽

Yanzhong LI ◽

...

Keyword(s):

Liquid Nitrogen ◽

Vertical Tube ◽

Numerical Prediction ◽

Subcooled Boiling ◽

Boiling Flow

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Subcooled Boiling Flow Heat Transfer From Plain and Enhanced Surfaces in Automotive Applications

Journal of Heat Transfer ◽

10.1115/1.2780178 ◽

2008 ◽

Vol 130 (1) ◽

Cited By ~ 14

Author(s):

Franz Ramstorfer ◽

Helfried Steiner ◽

Günter Brenn ◽

Claudius Kormann ◽

Franz Rammer

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

Nucleate Boiling ◽

Heated Wall ◽

Transfer Model ◽

Subcooled Boiling ◽

Cooling Systems ◽

Porous Coatings ◽

Transfer Rates ◽

Boiling Flow

The requirement for the highest possible heat transfer rates in compact, efficient cooling systems can often only be met by providing for a transition to subcooled boiling flow in strongly heated wall regions. The significantly higher heat transfer rates achievable with boiling can help keep the temperatures of the structure on an acceptable level. It has been shown in many experimental studies that special surface finish or porous coatings on the heated surfaces can intensify the nucleate boiling process markedly. Most of those experiments were carried out with water or refrigerants. The present work investigates the potential of this method to enhance the subcooled boiling heat transfer in automotive cooling systems using a mixture of ethylene-glycol and de-ionized water as the coolant. Subcooled boiling flow experiments were carried out in a vertical test channel considering two different types of coated surfaces and one uncoated surface as a reference. The experimental results of the present work clearly demonstrate that the concept of enhancing boiling by modifying the microstructure of the heated surface can be successfully applied to automotive cooling systems. The observed increase in the heat transfer rates differ markedly for the two considered porous coatings, though. Based on the experimental data, a heat transfer model for subcooled boiling flow using a power-additive superposition approach is proposed. The model assumes the total wall heat flux as a nonlinear combination of a convective and a nucleate boiling contribution, both obtained from well-established semiempirical correlations. The wall heat fluxes predicted by the proposed model are in very good agreement with the experimental data for all considered flow conditions and surface types.

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