An investigation on the microwave heating of flowing water: A numerical study

Yousefi, Tooraj; Mousavi, Seyyed Arash; Saghir, M. Ziad; Farahbakhsh, B.

doi:10.1016/j.ijthermalsci.2013.04.006

Cited by 33 publications

(21 citation statements)

References 21 publications

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“…The moisture determines the dielectric properties of the materials and ions content because both control the depth of penetration of the waves in the material. [37]. Dielectric materials have relaxation frequencies, equivalent to the time where the energy is absorbed and emitted by effect of the electric field.…”

Section: Fundamentals Of Microwave Heating Processingmentioning

confidence: 99%

“…Liquids heating with microwaves have uneven heating distribution in the water flowing due to non-uniform electric field patterns. Uniformity in liquid layer heating can be solved by utilizing a focused system and taking in account factors which influence the heating patterns like dielectric properties, ionic concentration, volume, and product shape [37,44].…”

Section: Microwave Heating Modelingmentioning

confidence: 99%

See 1 more Smart Citation

Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview

Aguilar-Reynosa

Romaní

Rodríguez-Jasso

et al. 2017

Energy Conversion and Management

296

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The development of a feasible biorefinery is in need of alternative technologies to improve lignocellulosic biomass conversion by the suitable use of energy. Microwave heating processing (MHP) is emerging as promising unconventional pretreatment of lignocellulosic materials (LCMs). MHP applied as pretreatment induces LCMs breakdown through the molecular collision caused by the dielectric polarization. Polar particles movement generates a quick heating consequently the temperatures and times of process are lower. In this way, MHP has positioned as green technology in comparison with other types of heating. Microwave technology represents an excellent option to obtain susceptible substrates to enzymatic saccharification and subsequently in the production of bioethanol and high-added compounds. However, it is still necessary to study the dielectric properties of materials, and conduct economic studies to achieve development in pilot and industrial scale. This work aims to provide an overview of recent progress and alternative configurations for combining the application of microwave technology on the pretreatment of LCMs in terms of biorefinery.

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Section: Fundamentals Of Microwave Heating Processingmentioning

confidence: 99%

Section: Microwave Heating Modelingmentioning

confidence: 99%

Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview

Aguilar-Reynosa

Romaní

Rodríguez-Jasso

et al. 2017

Energy Conversion and Management

296

View full text Add to dashboard Cite

show abstract

“…And the wall will also ensure the security for the usage of microwave further. By using Faraday's law and Gauss' theorem [24], the perfect boundary condition can be given as…”

Section: Estimating Internal Heat Sourcementioning

confidence: 99%

Approximate finite-dimensional ODE temperature model for microwave heating

Zhong

Lianga

Zeng

et al. 2016

NAMC

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In this paper, a finite-dimensional ordinary differential equation (ODE) model is proposed for predicting the temperature profile with microwave heating to accomplish lower computing complexity. The traditional parabolic partial different equation (PDE) model with integrating Maxwell's equation and heat transport equation is not suitable for designing the on-line controller. Based on the obstruction, using an auxiliary function derives an intermediate model, which is analyzed and discussed for model reduction by employing the parameter separation method and Galerkin's method. The simulation experiments on one-dimensional waveguide and cavity demonstrate that the proposed approximate model is effective.

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“…Recently, MWs are being utilized to heat continuous flow of liquids [6] and specifically, of water [7]. Related benefits concern the increased productivity, easier clean up and process automation compared to standard batch systems [8] in which the outward of the heat exchanger heats first and then heat is transferred to the inner liquid.…”

Section: Introductionmentioning

confidence: 99%

Toward an Improved Hybrid Model for Simulating Continuous Flow Microwave Heating of Water

2020

International Journal of Communications

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This paper introduces an improved hybrid (numerical-analytical) model for simulating microwave (MW) heating of laminar duct flow. The proposed procedure links numerical results to analytical calculations, providing a tool for accurate prediction of the bulk temperature distribution in a relatively reduced computation time, enhancing the design of MW heating of continuous flow water systems. The hybrid solution was obtained by first numerically solving the Maxwell equations in correspondence of an average dielectric permittivity; discrete values of the cross-section averaged heat generation arising from the numerical solution were first corrected by a suitable weighting function and then interpolated by a function resulting from the discrete Fourier series. The momentum and the energy equations fed by the above calculated heat generation distribution were uncoupled from Maxwell equations. The problem being linear, the analytical thermal solution was sought as the sum of two partial solutions, each one affected by a single non-homogeneity. The former solution turned out to be the classical Graetz problem, while the second one, driven by the heat generation, was solved in closed form by the variation of parameters method. On the other hand, the same problem was solved by a complete numerical approach in order to have a reference solution; thus, the Maxwell equations and the energy balance for the flowing fluid were simultaneously solved considering temperature dependent dielectric permittivity. Fully developed velocity, thermally developing conditions and no phase transition during the heating process were assumed for both the hybrid and the numerical solution. The availability of the reference solution allowed to prove the substantial enhancement of the hybrid solution in describing the bulk temperature distribution along the pipe when compared to the one related to the classical constant properties approach. Results, presented and discussed for different inlet velocities, show that increasing velocities provide a better agreement due to the smoothing effect realized by higher frequencies fluctuations in heat generation distribution felt by the flowing fluid.

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An investigation on the microwave heating of flowing water: A numerical study

Cited by 33 publications

References 21 publications

Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview

Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview

Approximate finite-dimensional ODE temperature model for microwave heating

Toward an Improved Hybrid Model for Simulating Continuous Flow Microwave Heating of Water

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