A maximum entropy production model for Teflon ablation by arc radiation

Abstract

In the framework of the maximum entropy production rate principle, a simple model for Teflon material ablation by arc radiation is introduced. The model predicts a vapour temperature T and an effective ablation enthalpy Δheff of about 3200 K and 11 MJ kg−1, respectively. These values are constant for radiation fluxes Qrad ≪ pΔheff/c (≈1010 W m−2 at pressure p ≈ 10 bar and sound velocity c≈ 103 m s−1). For larger Qrad the model is not self-consistent and must be generalized. In the range of self-consistency, the results are in accordance with observations reported in the relevant literature on nozzle ablation in gas circuit breakers or model tubes.

PTFE Vapor Contribution to Pressure Changes in High-Voltage Circuit Breakers

“…In order to determine T vap , the temperature of the vapor of the ablated PTFE and h PTFE−vap the enthalpy needed for wall ablation, we used the approach proposed in [22]. The work is based on the maximum entropy principle (MEP).…”

“…The MEP assumes that an out-of-equilibrium system will produce an entropy maximum to reach the equilibrium state as fast as possible. Based on [22], the vapor temperature T vap is obtained by the maximization of the entropy production rateδ…”

Steady state of a dissipative flow-controlled system and the maximum entropy production principle

“…The Earth climate models include quite accurate predictions of the mean latitudinal air temperature, fractional cloud cover, meridional heat flux [1], mean vertical air temperature profile, vertical heat flux [4] and historical latitudinal air temperature gradients over decadal and glacial-interglacial time scales [12]. The MEP principle has also been invoked for the explanation of shear turbulence (Couette flow) [17], incompressible and compressible turbulent fluid flow [26], currents in electrical circuits [27,28,29,30], plasma formation [31] and structure [32], crystal growth [33], chemical cycle kinetics [34], diffusion in non-uniform solids [35], photosynthesis mechanism [36], biomolecular motors [37] and economic activity [38]; several detailed reviews are available [9,11,39,40]. The MEP principle has even been invoked as a technical basis for the Gaia hypothesis * Electronic address: r.niven@adfa.edu.au [10,21,41,42].…”

Modeling Electric Discharges with Entropy Production Rate Principles

“…We will show elsewhere that the same can appear for electron transport in matter [27]. Another example, which points into this direction, is radiation induced material ablation [28]. There, MEPP was used to determine the vapor temperature and the ablation rate, parameters that enter into the boundary condition of the hydrodynamic balance equations for electric arc simulations.…”