Publisher Summary This chapter serves as a useful synopsis of the field of electrohydrodynamically (EHD) coupled heat transfer in liquids, so the equations of motion are those of a viscous incompressible fluid. An exhaustive published bibliography of work on EHD coupled heat transfer is provided and reviews the principal contributions made by Kronig and Ahsmann. The conventional formulation of the equations of EHD is provided to facilitate discussion of various theoretical contributions. The classification of important parameters used in EHD heat-transfer research is summarized. Some important aspects of EHD coupled heat-transfer enhancement including a succinct set of conditions that define the various regimes are reviewed. Specific application of the complex electrohydrodynamic mechanisms involved in EHD coupled heat transfer in liquids is considered. Potential applications of EHD heat transfer include general enhancement of pool boiling for heat exchanger equipment. Certain advantages and disadvantages of EHD coupled heat transfer in low temperature and cryogenic high-voltage cables should be assessed. The boiling and condensation heat transfer and basic configuration of an EHD heat pipe using electromechanical flow structure to promote condensate return flow are diagrammatically represented. The list of experimental observations and theoretical conclusions are summarized and the principal results of the papers are reviewed.

Electrohydrodynamically Enhanced Heat Transfer in Liquids—A Review

The macroscopic temperature and pressure jumps that occur at a condensate surface during a nonequilibrium phase change are calculated using a variational principle on the linearized Boltzmann equation. When evaluated for the BGK collisional model, the macroscopic jumps have values within 1% of a recent numerical calculation. Furthermore, the microscopic density and temperature jumps are estimated using an ansatz for the distribution function of molecules impinging on the surface. The jumps obtained in this way are correct to within 5% of the numerical values when evaluated for the BGK model. Also a simple procedure is described by which the jumps occuring at a surface for which the mass accommodation (condensation) coefficient σ≠1 may be calculated from those for which σ=1. In addition the connection of this kinetic theory with the thermodynamics of irreversible processes is made and the elements of the appropriate Onsager matrix are expressed in terms of the macroscopic jumps for arbitrary values of σ.

Kinetic theory of condensation and evaporation. II

Heat transfer—A review of 1972 literature

Following the principles of the thermodynamics of irreversible processes of discontinuous system a theory of boundary conditions for the liquid-vapour interface of helium II is developed. Neglecting the influences of the coefficients of viscosity in the liquid and the gas, the surface tension of the liquid and surface currents, boundary conditions are inferred from the conservation laws of mass, momentum and energy including all non-linear terms. It is shown that two further boundary conditions for the net mass and energy transfer rates through the free surface of helium II can be obtained from the entropy balance. In the case of non-equilibrium processes occurring at the surface, net flows of mass and energy through the phase boundary result.

https://iopscience.iop.org/article/10.1088/0022-3719/9/4/006/pdf

Boundary conditions for the liquid-vapour interface of helium II

Our knowledge of heat transfer associated with boiling and condensation has been advanced considerably in the last two decades from the mysterious experimental data for overall coefficients for special geometrical arrangements to some rather detailed descriptions of mechanisms of various aspects of the processes. Nevertheless, there remain today many unanswered questions. In the following the state of art of various aspects of boiling and condensation will be presented along with some of the significant unanswered questions.

Status of and problems in boiling and condensation heat transfer

The object of this work is to determine the transport coefficients which appear in linear irreversible-thermodynamic rate equations of a phase change. An experiment which involves the steady-state evaporation of mercury was performed to measure the principal transport coefficient appearing in the mass-rate equation and the coupling transport coefficient appearing in both the mass-rate equation and the energy-rate equation. The principal transport coefficient sigma, usually termed the 'condensation' or 'evaporation' coefficient, is found to be approximately 0.9, which is higher than that measured previously in condensation-of-mercury experiments. The experimental value of the coupling coefficient K does not agree with the value predicted from Schrage's kinetic analysis of the phase change. A modified kinetic analysis in which the Onsager reciprocal law and the conservation laws are invoked is presented which removes this discrepancy but which shows that the use of Schrage's equation for predicting mass rates of phase change is a good approximation.

/pdf/a-study-of-the-liquid-vapor-phase-change-of-mercury-based-on-12c4wzia4w.pdf

A study of the liquid-vapor phase change of mercury based on irreversible thermodynamics.

Steady state mercury evaporation experiment to measure transport coefficient in liquid-vapor interface boundary condition study

/pdf/bubble-formation-and-growth-study-of-the-boundary-conditions-18f0p33uag.pdf

Bubble Formation and Growth. Study of the Boundary Conditions at a Liquid-vapor Interface Through Irreversible Thermodynamics Quarterly Progress Report, Jun. - Aug. 1965

G. N. Hatsopoulos

Papers

A study of the liquid-vapor phase change of mercury based on irreversible thermodynamics.

Bubble Formation and Growth. Study of the Boundary Conditions at a Liquid-vapor Interface Through Irreversible Thermodynamics Quarterly Progress Report, Jun. - Aug. 1965