Discussion: “The Latent Heat of Vaporization of a Widely Diverse Class of Fluids” (Torquato, S., and Smith, P., 1984, ASME J. Heat Transfer, 106, pp. 252–254)

Heat recovery plays an important role in all energy systems. The dissipation of heat is drastically increasing due to the advancement of electronic components. To cool the electronic components many heat recovery devices are introduced and out of which heat pipes play an important role. Pulsating Heat Pipe (PHP) is a new type of heat transfer device which was introduced by Akachi in mid-1990. It is used mainly in the cooling of electronic components because of its potential for removing high heat flux. An experimental study was made to investigate the heat transfer performance of PHP using self-rewetting fluids of high carbon alcohols. The latent heat of vaporization plays an important role in the heat transfer performance of PHP. It was observed that the high carbon alcohols showed a decrease in the latent heat of vaporization. The high carbon alcohols such as 1-Butanol, 1-Pentanol, 1-Hexanol, 1-Heptanol, and 1-Octanol were mixed with the deionized water to form a self-rewetting fluid. These self-rewetting fluids showed a unique behavior due to the inverse Marangoni effect. It was observed that the lower thermal resistance and higher heat transfer coefficient was obtained, especially in the dilute aqueous solution of 1- Octanol.

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Influence of Working Fluid Thermophysical Property on Thermal Performance of Flat-Plate Closed Loop Pulsating Heat Pipe

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.130-134.1799 ◽

2011 ◽

Vol 130-134 ◽

pp. 1799-1804 ◽

Cited By ~ 5

Author(s):

Qing Ping Wu ◽

Rui Xiang Wang ◽

Ya Jun Li ◽

Rong Ji Xu ◽

Yan Zhong Li

Keyword(s):

Heat Transfer ◽

Surface Tension ◽

Latent Heat ◽

Thermal Performance ◽

Thermophysical Properties ◽

Closed Loop ◽

Heat Pipes ◽

Working Fluid ◽

Heat Of Vaporization ◽

Latent Heat Of Vaporization

Pulsating heat pipes are high efficiency heat transfer components having a great potential application in the field of electronic cooling and space applications. In this investigation, an experiment was conducted to study the influence of working fluid thermophysical properties on the thermal performance of flat-plate closed loop pulsating heat pipes (FCLPHP). The analysis of the forces acting on the liquid-vapor mixture shows that the surface tension, viscosity and latent heat of vaporization have important impact on the thermal performance of FCLPHP. The overall thermal resistance decreases with the decrease in surface tension, viscosity and latent heat of vaporization, leading to the heat transfer improvement of FCLPHP. An experimental correlation was developed to describe the relationship among the relative overall thermal resistance and the relative thermophysical properties. With the correlation, a sensitivity analysis was made. The results show that latent heat of vaporization is the prior factor to the all others to impact the thermal performance of FCLPHP.

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Direct Simulation of Spray Cooling: Effect of Multiple Droplet Impact and Latent Heat of Vaporization of Coolant Liquid on Heat Transfer

Heat Transfer: Volume 2 ◽

10.1115/ht2008-56034 ◽

2008 ◽

Author(s):

Mita Sarkar ◽

R. Panneer Selvam ◽

Rengasamy Ponnappan

Keyword(s):

Heat Transfer ◽

Liquid Film ◽

Latent Heat ◽

Stokes Equations ◽

Thin Liquid Film ◽

Spray Cooling ◽

Droplet Impact ◽

Vapor Bubbles ◽

Heat Of Vaporization ◽

Latent Heat Of Vaporization

Spray cooling is a way of efficiently removing the heat from a hot surface and considered for high power system such as advanced lasers. The heat transfer phenomenon in spray cooling is complex in nature because it occurs due to conduction, convection and phase change. The numerical model of spray cooling is done by solving the set of incompressible Navier-Stokes equations using finite difference method. Level set method is used to capture the liquid vapor interface in our multiphase flow model. Our previous 2D model which included single droplet impact on single growing vapor bubble is modified to introduce multiple droplets impact on thin liquid film with multiple growing vapor bubbles. Though the previous model was effective so far to predict the spray cooling phenomena and also the parameters for high heat removal, but the actual spray cooling phenomena consists of multiple droplets impact on multiple growing vapor bubbles at different time instances. To understand the spray cooling further and to represent it more realistically the inclusion of multiple droplets and multiple vapor bubbles is essential. In the present work, an investigation on the effect of latent heat of vaporization of coolant is conducted for the case of a thin liquid film of 44 μm in removing the heat and bubble growth when a liquid spray droplet is impacting. The flow and heat transfer details are presented for multiple droplet impacts on thin liquid film with multiple growing vapor bubbles.

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Impact of Fuel Properties on the Performances and Knock Behaviour of a Downsized Turbocharged DI SI Engine - Focus on Octane Numbers and Latent Heat of Vaporization

SAE International Journal of Fuels and Lubricants ◽

10.4271/2009-01-0324 ◽

2009 ◽

Vol 2 (1) ◽

pp. 118-126 ◽

Cited By ~ 33

Author(s):

Jean Milpied ◽

Nicolas Jeuland ◽

Gabriel Plassat ◽

Sabine Guichaous ◽

Nathalie Dioc ◽

...

Keyword(s):

Latent Heat ◽

Fuel Properties ◽

Si Engine ◽

Heat Of Vaporization ◽

Latent Heat Of Vaporization

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Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces

ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2013-22120 ◽

2013 ◽

Cited By ~ 1

Author(s):

Solomon Adera ◽

Rishi Raj ◽

Evelyn N. Wang

Keyword(s):

Thin Film ◽

Heat Transfer ◽

Heat Flux ◽

Phase Change ◽

Thermal Management ◽

Latent Heat ◽

Thin Film Evaporation ◽

Film Evaporation ◽

Microstructured Surfaces ◽

Latent Heat Of Vaporization

Thermal management is increasingly becoming a bottleneck for a variety of high power density applications such as integrated circuits, solar cells, microprocessors, and energy conversion devices. The performance and reliability of these devices are usually limited by the rate at which heat can be removed from the device footprint, which averages well above 100 W/cm2 (locally this heat flux can exceed 1000 W/cm2). State-of-the-art air cooling strategies which utilize the sensible heat are insufficient at these large heat fluxes. As a result, novel thermal management solutions such as via thin-film evaporation that utilize the latent heat of vaporization of a fluid are needed. The high latent heat of vaporization associated with typical liquid-vapor phase change phenomena allows significant heat transfer with small temperature rise. In this work, we demonstrate a promising thermal management approach where square arrays of cylindrical micropillar arrays are used for thin-film evaporation. The microstructures control the liquid film thickness and the associated thermal resistance in addition to maintaining a continuous liquid supply via the capillary pumping mechanism. When the capillary-induced liquid supply mechanism cannot deliver sufficient liquid for phase change heat transfer, the critical heat flux is reached and dryout occurs. This capillary limitation on thin-film evaporation was experimentally investigated by fabricating well-defined silicon micropillar arrays using standard contact photolithography and deep reactive ion etching. A thin film resistive heater and thermal sensors were integrated on the back side of the test sample using e-beam evaporation and acetone lift-off. The experiments were carried out in a controlled environmental chamber maintained at the water saturation pressure of ≈3.5 kPa and ≈25 °C. We demonstrated significantly higher heat dissipation capability in excess of 100 W/cm2. These preliminary results suggest the potential of thin-film evaporation from microstructured surfaces for advanced thermal management applications.

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THE ZERO-POINT KINETIC ENERGY OF LIQUID HELIUM

Canadian Journal of Physics ◽

10.1139/p55-095 ◽

1955 ◽

Vol 33 (12) ◽

pp. 797-800 ◽

Cited By ~ 5

Author(s):

D. G. Henshaw ◽

D. G. Hurst

Keyword(s):

Kinetic Energy ◽

Neutron Diffraction ◽

Liquid Helium ◽

Latent Heat ◽

Interatomic Potential ◽

Zero Point ◽

Potential Functions ◽

Point Temperature ◽

Heat Of Vaporization ◽

Latent Heat Of Vaporization

The zero-point kinetic energy of liquid helium has been calculated from the interatomic potential, the latent heat of vaporization, and atomic distributions derived from neutron diffraction measurements. Calculations were carried out for two liquid temperatures and several published interatomic potential functions. The resulting values of the "zero-point temperature" lie between 9.0°K. and 12.6°K.

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