Modeling for Temperature Distribution of Water in a Multiwaveguide Microwave Reactor

Chen, Ru-Jia; Qiao, Ning; Arowo, Moses; Zou, Hai‐Kui; Chu, Guang‐Wen; Luo, Yong; Sun, Baochang; Chen, Jian-Feng

doi:10.1021/acs.iecr.9b04748

Cited by 9 publications

(5 citation statements)

References 43 publications

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“…The COMSOL Multiphysics (V5.4a, COMSOL Inc., Sweden) was used to predict the temperature distribution of GNPs‐coated PEI beads in the MW reactor. The main steps in establishing the model include generating geometry, setting materials, adding physical fields, defining boundary conditions and initial value, meshing, solving, and analyzing results 22 . The COMSOL established MW oven was shown in Figure 2(a), which was the same dimensions (280 × 250 × 290 mm) to the experimental one.…”

Section: Methodsmentioning

confidence: 99%

“…The main steps in establishing the model include generating geometry, setting materials, adding physical fields, defining boundary conditions and initial value, meshing, solving, and analyzing results. 22 The COMSOL established MW oven was shown in Figure 2(a), which was the same dimensions (280 × 250 × 290 mm) to the experimental one. It should be noticed that only four beads (each was 2 mm in diameter by coated with 4-μm thickness MW absorbent layer) were built in our simulations (Figure 2 (b)), due to the limited computing source of our personal computer.…”

Section: Comsol Multiphysics Simulationsmentioning

confidence: 99%

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Microwave‐assisted rapid fabrication of robust polyetherimide bead foam parts

Feng

2020

J of Applied Polymer Sci

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Polyetherimide (PEI) is an important candidate for fabrication of highperformance polymer foams. Nevertheless, the manufacture of PEI foamed parts with specific three-dimensional geometry shape and lightweight properties remains a big challenge worldwide. Herein, a microwave (MW)-assisted foaming and selective sintering approach was proposed towards rapid fabrication of robust PEI bead foams. During the process, compressed carbon dioxide/tetrahydrofuran was used as physical co-foaming agent, and the surface-coated graphene nanoplatelets (GNPs) was used as MW absorbent. Upon MW irradiation, the GNPs selectively heated and served as solders that effectively facilitated the foaming of expandable PEI (EPEI) beads, and strongly promoted the local polymer melt and entanglement across the surface of EPEI beads. The MW irradiation power and time were considered as the important parameters to achieve fine inter-bead bonding strength between foamed beads. As a model system, we successfully fabricated a 25-mmthickness foamed part with an apparent density of 0.32 g/cm 3 and achieved excellent inter-bead bonding performance. Specifically, we also utilized the COMSOL Multiphysics simulations to study the MW selective heating mechanism. This MW-assisted fabrication strategy offers a new foaming approach toward high-performance polymer foamed parts for many advanced applications.

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Section: Methodsmentioning

confidence: 99%

Section: Comsol Multiphysics Simulationsmentioning

confidence: 99%

Microwave‐assisted rapid fabrication of robust polyetherimide bead foam parts

Feng

2020

J of Applied Polymer Sci

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“…As schematically depicted in Figure , heat transfer in a conventional heating approach is from the surface of a solid object to its core due to the shallow penetration depth of infrared waves. , However, materials do not follow the same phenomena when exposed to MWs. A higher penetration depth of MWs in materials than that of infrared waves results in their volumetric heating. − In the MW heating approach, because of heat loss from the surface, the central temperature is commonly higher than the surface temperature, which leads to heat transfer from the center of the object to its surface. , In addition, volumetric heating by MWs happens when the solid particle size of a MW absorber material is optimally smaller than the MW’s penetration depth…”

Section: Introductionmentioning

confidence: 99%

Temperature Distribution Assessment in Gas–Solid Reactive and Nonreactive Systems Heated by Microwaves

Adavi

Shabanian

Chaouki

2023

Ind. Eng. Chem. Res.

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Research studies have shown that selective heating of different phases in gas−solid systems exposed to microwave (MW) irradiation leads to a temperature gradient between gas and MW absorber solids. This can suppress undesired secondary gas-phase reactions and yield apparent kinetic improvements and energy savings. However, the effects of reaction exothermicity/ endothermicity, gas velocity, temperature probe location at the microscale, and MW penetration depth in fixed beds on the temperature difference between solid and gas phases exposed to MWs and temperature distribution in the fixed beds are poorly understood. Highlighting these effects was targeted in this study and accomplished with the help of multiphysics simulations by COMSOL Multiphysics (5.6). The corresponding COMSOL model was initially verified and validated by data collected from literature studies and those obtained experimentally by the authors in this study. Simulation results from the verified and validated model indicated that the temperature gradient between the gas and the MW absorber solid increases by increasing the gas velocity or switching from an endothermic reaction to no reaction and/or an exothermic reaction. In addition, the collected results show nonuniform temperature distribution in a fixed-bed reactor made of MW absorber particles irradiated by MWs due to the limited penetration depth of MWs and hotspot formation. This operational deficiency makes the large-scale design of this type of reactor very challenging for MW heating-assisted reactions.

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“…Yi used a conveyor belt and a mode stirrer together and obtained a better heating performance than using them individually [ 21 ]. In addition, research has been conducted to improve heating performance by changing the geometry of the cavities [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Several studies applied multiple waveguides [ 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, research has been conducted to improve heating performance by changing the geometry of the cavities [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Several studies applied multiple waveguides [ 23 , 24 ]. As another approach, Hong analyzed the heating performance by changing the frequency and power of the microwave and position of target materials [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Design of Large-Scale Microwave Cavity for Uniform and Efficient Plastic Heating

2022

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To reduce carbon emissions during heating in the manufacturing processes, microwave technology has attracted significant attention. Microwaves have considerable advantages over traditional heating methods, including more rapid heating, lower thermal damage, and eco-friendly processes. To apply microwaves to the manufacturing process, uniform and efficient heating is required. We analyzed the effect of various design parameters for uniform and efficient heating by changing the cavity heights, application of the reflector, and number and positions of waveguides. We conducted a numerical simulation and verified the findings by experiments. The results showed that a slight change in the cavity height altered the electromagnetic field distribution and heating parameters, such as the coefficient of variance and power absorption efficiency. With reflectors installed, 66% of cases exhibited better comprehensive evaluation coefficient (CEC) with consideration of uniform heating and power absorption. The spherical reflector showed 81% of cases, better than those of the ordinary model without a reflector. Furthermore, when double waveguides were installed, the average coefficient of variance (COV) was improved by 22%, and power absorption efficiency was increased by 53% compared to the single waveguide case. When the power applied to the waveguides was doubled, the average COV values improved by 18%. This large-scale analysis will be helpful in applying microwaves to actual industrial sites.

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Modeling for Temperature Distribution of Water in a Multiwaveguide Microwave Reactor

Cited by 9 publications

References 43 publications

Microwave‐assisted rapid fabrication of robust polyetherimide bead foam parts

Microwave‐assisted rapid fabrication of robust polyetherimide bead foam parts

Temperature Distribution Assessment in Gas–Solid Reactive and Nonreactive Systems Heated by Microwaves

Design of Large-Scale Microwave Cavity for Uniform and Efficient Plastic Heating

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