Classical molecular dynamics simulation of microwave heating of liquids: The case of water

Abstract

We perform a complete classical molecular dynamics study of the dielectric heating of water in the microwave (MW) region. MW frequencies ranging from 1.0 to 15.0 GHz are used together with a series of well-known empirical force fields. We show that the ability of an empirical force field to correctly predict the dielectric response of liquids to MW radiation should be evaluated on the basis of a joint comparison of the predicted and experimental static dielectric constant, frequency-dependent dielectric spectra, and heating profiles. We argue that this is essential when multicomponent liquids are studied. We find that both the three-site OPC3 and four-site TIP4P-ϵ empirical force fields of water are equally superior for reproducing dielectric properties at a range of MW frequencies. Despite its poor prediction of the static dielectric constant, the well-known SPCE force field can be used to accurately describe dielectric heating of water at low MW frequencies.

Multidirectional Polarization Impacts on Microwave Heating Efficiency: A Molecular Dynamics Research of Microwave Heating of Common Solvents

“…The frequency-dependent dielectric constant can be calculated using the determined τ D through the following equation from the Debye relaxation model: ε normalR normale ( ω ) = ε ∞ + ε normals − ε ∞ 1 + ω 2 τ normalD 2 ε normalI normalm ( ω ) = ( ε s − ε ∞ ) ω τ normalD 1 + ω 2 τ normalD 2 where ε ∞ and ε s are the infinite frequency dielectric constant and static dielectric constant, respectively. It should be emphasized that all of the ε ∞ and ε s values employed in our calculation of these dielectric spectra are experimental values that were obtained from the literature. − The corresponding values are presented in Table . In this Article, the frequency range of the frequency-dependent dielectric spectra is from 300 MHz to 300 GHz.…”

“…h i b i t e d .using the determined τ D through the following equation from the Debye relaxation model:31 …”

Molecular dynamics simulation of microwave heating of liquid monoethanolamine (MEA): An evaluation of existing force fields

“…We recently reported on classical MD simulations of the dielectric heating of liquid water using MW radiation at different frequencies 2 . We concluded that the capability of an empirical force field to correctly predict the dielectric response of liquids to MW radiation should be evaluated on the basis of a joint comparison of the predicted and experimental static dielectric constant, frequency-dependent dielectric spectra, and MW heating rates.…”

“…The use of pure MEA liquid in CO 2 capture is not feasible because of the high viscosity of the product. However, the temperature required for CO 2 In Figure 1 we illustrate the molecular geometry of the MEA molecule. In this paper we care-fully evaluate the accuracy of most available empirical force fields of MEA, namely MEAa2007 8 , MEAo2007 8 , MEAa2015 9 , OPLS-aa 10 , OPLS-aam 10 , GROMOS-aa 11,12 , and GROMOS-ua 11,12 .…”

“…For instance, use of MW dielectric heating in a carbon capture process to regenerate the amine solvent could potentially reduce the overall cost of the process 1 . In order to understand the role of MW in this CO 2 capture process, details of the dielectric response of the employed liquids to MW irradiation are required. These details include an accurate determination of static dielectric constant, frequencydependent dielectric spectra, and heating rates of these liquids at different MW frequencies.…”