Publication

Boiling of R–134 and R–123 in a microfin tube.

Daniel Favrat
1995
Reports

Abstract

Local flow boiling heat transfer coefficients were measured for R-134a and R- 123 evaporating inside a microfin tube for horizontal flow and vertical upflow over a wide range of mass velocities, vapor qualities and heat flux. The objective was to study the effect of tube orientation on microfin heat transfer, primarly to gain more insight into how microfin tubes augment heat transfer. In addition microfin heat transfer augmentation relative to previously measured plain tube test data was investigated. The experiments showed a significant effect of flow direction on local microfin heat transfer coefficients with horizontal flow surprisingly giving better heat transfer than upflow. In addition, the relative level of augmentation increased significantly with local vapor quality.

Official source

https://infoscience.epfl.ch/entities/publication/7f9f93d7-dcd7-4833-841a-f9777517f7a9

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Daniel Favrat
1995
Reports

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/7f9f93d7-dcd7-4833-841a-f9777517f7a9

About this result

Related concepts (32)

Heat transfer coefficient

In thermodynamics, the heat transfer coefficient or film coefficient, or film effectiveness, is the proportionality constant between the heat flux and the thermodynamic driving force for the flow of heat (i.e., the temperature difference, ΔT ). It is used in calculating the heat transfer, typically by convection or phase transition between a fluid and a solid. The heat transfer coefficient has SI units in watts per square meter per kelvin (W/m2/K).

Heat

In thermodynamics, heat is the thermal energy transferred between systems due to a temperature difference. In colloquial use, heat sometimes refers to thermal energy itself. An example of formal vs. informal usage may be obtained from the right-hand photo, in which the metal bar is "conducting heat" from its hot end to its cold end, but if the metal bar is considered a thermodynamic system, then the energy flowing within the metal bar is called internal energy, not heat.

Heat transfer

Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species (mass transfer in the form of advection), either cold or hot, to achieve heat transfer.

Related publications (1)

Boiling of R–134 and R–123 in a microfin tube.

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