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Device Testing: High-Efficiency and High-Uniformity Microwave Water Treatment System Based on Horn Antennas. Processes (Basel) 2023. [DOI: 10.3390/pr11030826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
Microwave heating has excellent potential for applications in wastewater treatment. This study proposes a highly efficient continuous liquid-phase microwave heating system to overcome the problems of low treatment capacity, low dynamic range of loads, and insufficient heating uniformity of the existing equipment. First, a quarter-wavelength impedance-matching layer improves heating efficiency, and the heating uniformity has been enhanced by horn antennas. Second, an experimental system is developed. The simulation and experimental results are consistent, with the microwave system achieving over 90% energy utilization for different thicknesses and concentrations of salt water. Finally, simulations are performed to analyze microwave efficiency and heating uniformity at different flow rates, salinities, dielectric properties, and sawtooth structures. The system can efficiently heat loads with a wide range of dielectric properties, including saline water. Generally, when the permittivity varies from 10 to 80, and the loss tangent varies dynamically from 0.15 to 0.6, more than 90% of microwave efficiency and excellent temperature distribution (The coefficient of temperature variation COV < 0.5) can be achieved. The system’s modular design enables scaling up to further boost processing capacity. Overall, the system provides high-throughput, high-efficiency, high-uniformity, and large-dynamic-range microwave water treatment, which has promising applications in industrial water treatment.
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2
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Guo J, Zhu H, Yang Y, Guo Q. Continuous-Flow Microwave Milk Sterilisation System Based on a Coaxial Slot Radiator. Foods 2023; 12:foods12030459. [PMID: 36765988 PMCID: PMC9914817 DOI: 10.3390/foods12030459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/14/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Microwave continuous-flow liquid food sterilisation, in which the liquid is mainly heated by microwaves, has the advantages of fast sterilisation speed, energy saving, comprehensive elimination, and less nutrient loss. Circular pipes are commonly used in microwave continuous-flow liquid heating processing. However, with circular pipes, which are widely used in the industry, the heating is uneven owing to the phenomenon of tube focusing when adopting external radiation. In this study, a novel microwave continuous-flow milk sterilisation system based on a coaxial slot radiator is proposed. First, the coaxial slot radiator was designed to realise efficient radiation through the establishment of multi-physics model. The structure of the system was then optimised by comparing the heating efficiency and uniformity of simulation results. The effect of microwave coaxial slot radiator rotation on heating uniformity was simulated and the results show that the heating uniformity is improved obviously. Experimental equipment was set up to verify the results of the simulation. The experimental results are consistent with the simulation results. Finally, the sensitivity analysis of the system is performed to confirm that, when the dielectric properties and types of liquid food change, the heating of the proposed microwave continuous-flow system remains efficient and uniform.
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3
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Suresh RR, Kulandaisamy AJ, Nesakumar N, Nagarajan S, Lee JH, Rayappan JBB. Graphene Quantum Dots – Hydrothermal Green Synthesis, Material Characterization and Prospects for Cervical Cancer Diagnosis Applications: A Review. ChemistrySelect 2022. [DOI: 10.1002/slct.202200655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Raghavv Raghavender Suresh
- Department of Bioengineering School of Chemical & Biotechnology SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
- Centre for Nanotechnology & Advanced Biomaterials (CeNTAB) SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
| | - Arockia Jayalatha Kulandaisamy
- Centre for Nanotechnology & Advanced Biomaterials (CeNTAB) SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
- School of Electrical & Electronics Engineering SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
| | - Noel Nesakumar
- Department of Bioengineering School of Chemical & Biotechnology SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
- Centre for Nanotechnology & Advanced Biomaterials (CeNTAB) SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
| | - Saisubramanian Nagarajan
- Center for Research in Infectious Diseases (CRID) School of Chemical and Biotechnology SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
| | - Jung Heon Lee
- Research Center for Advanced Materials Technology School of Advanced Materials Science & Engineering Biomedical Institute for Convergence at SKKU (BICS) Sungkyunkwan University (SKKU) Suwon 16419 South Korea
| | - John Bosco Balaguru Rayappan
- Centre for Nanotechnology & Advanced Biomaterials (CeNTAB) SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
- School of Electrical & Electronics Engineering SASTRA Deemed University Thanjavur 613 401 Tamil Nadu India
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Altin O, Skipnes D, Skåra T, Erdogdu F. A computational study for the effects of sample movement and cavity geometry in industrial scale continuous microwave systems during heating and thawing processes. INNOV FOOD SCI EMERG 2022. [DOI: 10.1016/j.ifset.2022.102953] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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5
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Development of a complementary-frequency strategy to improve microwave heating of gellan gel in a solid-state system. J FOOD ENG 2022. [DOI: 10.1016/j.jfoodeng.2021.110763] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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6
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Improvement of Heating Uniformity by Limiting the Absorption of Hot Areas in Microwave Processing of CFRP Composites. MATERIALS 2021; 14:ma14247769. [PMID: 34947363 PMCID: PMC8709209 DOI: 10.3390/ma14247769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/04/2021] [Accepted: 12/08/2021] [Indexed: 11/29/2022]
Abstract
Carbon fiber reinforced polymer (CFRP) composites are integral to today’s industries. Curing or consolidation are vital processes for manufacturing CFRP components. Microwave processing has many advantages compared with conventional processing technologies using ovens or autoclaves; however, the uneven temperature distribution caused by the non-uniform microwave field has a significant influence on the quality of the cured products. In this study, we propose a new idea to solve this problem, i.e., limiting the absorption of hot areas. Under such circumstances, cold ones can catch up with them more easily. To adjust the absorbing capability of the CFRP laminate, periodically arranged metallic resonance structures supported by a dielectric spacer are introduced on its surface. The dielectric spacer, made of epoxy matrix and strontium titanate particles, is designed to possess a dielectric constant positively related to temperatures. In this situation, the microwave absorption (2.45 GHz) of the metal-dielectric-CFRP configuration is changed from 97.6% at room temperature to 55.9% at 150 °C continuously. As a result, a reduction of 43.1% in maximum temperature difference and 89% in standard deviation has been achieved.
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Yang R, Chen J. Mechanistic and Machine Learning Modeling of Microwave Heating Process in Domestic Ovens: A Review. Foods 2021; 10:foods10092029. [PMID: 34574139 PMCID: PMC8464961 DOI: 10.3390/foods10092029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 11/24/2022] Open
Abstract
The domestic microwave oven has been popularly used at home in heating foods for its rapid heating rate and high power efficiency. However, non-uniform heating by microwave is the major drawback that can lead to severe food safety and quality issues. In order to alleviate this problem, modeling of microwave heating process in domestic ovens has been employed to simulate and understand the complicated interactions between microwaves and food products. This paper extensively reviews the mechanistic models with different geometric dimensions and physics/kinetics that simulated the microwave heating process. The model implementation and validation strategies related to the model accuracy and efficiency are also discussed. With the emergence of the machine learning technique, this paper also discusses the recent development of hybrid models that integrate machine learning with mechanistic models in improving microwave heating performance. Besides, pure machine learning models using only experimental data as input are also covered. Further research is needed to improve the model accuracy, efficiency, and ease of use to enable the industrial application of the models in the development of microwave systems and food products.
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Sirohi R, Tarafdar A, Kumar Gaur V, Singh S, Sindhu R, Rajasekharan R, Madhavan A, Binod P, Kumar S, Pandey A. Technologies for disinfection of food grains: Advances and way forward. Food Res Int 2021; 145:110396. [PMID: 34112399 DOI: 10.1016/j.foodres.2021.110396] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/30/2021] [Accepted: 05/06/2021] [Indexed: 10/21/2022]
Abstract
Growing demand from the consumers for minimally processed and high-quality food products has raised the scientific quest for foods with improved natural flavours in conjunction with a restricted supplement of additives. In this context, achieving quality and safe food grains and the identification of suitable processing and disinfection technologies have also become the key issues. Microbial contamination is one of the major reasons responsible for the spoilage of food grains. Various sources of contamination such as air and water (both contaminated with dust and dirt), animals (insects, birds, rodents), environmental conditions (rainfall, drought, temperature), unhygienic handling, harvesting, processing equipment and improper storage conditions are responsible for the microbial spoilage of food grains. In order to maintain the food grains safe and un-contaminated, several food processing technologies have been explored and implemented, with the ultimate purpose of maintaining the safety, freshness and nutritional attributes of the food products. Among these technologies, microwave, radiofrequency, infrared, ohmic heating, novel drying methods along with non-thermal methods such as cold plasma, irradiation, ozonation and nanotechnology have attracted much attention because of considerable reduction in the overall processing time with minimum energy consumption. This review aims to discuss the advances involving the said technologies for controlling the microbial contamination of food grains in accordance with their inactivation. Current research status of the thermal and non-thermal emerging technologies for the preservation of food grains as well as perspectives for further research in this area are also elaborated in detail.
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Affiliation(s)
- Ranjna Sirohi
- Centre for Energy and Environmental Sustainability, Lucknow 226 029, Uttar Pradesh, India; Technology Development Centre, CSIR-National Environmental Engineering Research Institute, Nagpur 440 020, India; Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Ayon Tarafdar
- Divison of Livestock Production and Management, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India
| | - Vivek Kumar Gaur
- Environment Toxicology Division, CSIR-Indian Institute of Toxicology Research, Lucknow 226 001, India
| | - Shikhangi Singh
- Department of Post Harvest Process and Food Engineering, G.B. Pant University of Agriculture and Technology, Pantnagar 263 145, India
| | - Raveendran Sindhu
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, India
| | | | - Aravind Madhavan
- Rajiv Gandhi Centre for Biotechnology, Trivandrum, 695 014, India
| | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, India
| | - Sunil Kumar
- Technology Development Centre, CSIR-National Environmental Engineering Research Institute, Nagpur 440 020, India
| | - Ashok Pandey
- Centre for Energy and Environmental Sustainability, Lucknow 226 029, Uttar Pradesh, India; Center for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow 226 001, India; Faculty of Applied Sciences, Durban University of Technology, Durban 4000 South Africa.
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Zhou J, Yang X, Chu Y, Li X, Yuan J. A novel algorithm approach for rapid simulated microwave heating of food moving on a conveyor belt. J FOOD ENG 2020. [DOI: 10.1016/j.jfoodeng.2020.110029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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10
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Taheri S, Brodie G, Gupta D. Fluidisation of lentil seeds during microwave drying and disinfection could prevent detrimental impacts on their chemical and biochemical characteristics. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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A Fast and Accurate Method for Computing the Microwave Heating of Moving Objects. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10082985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this paper, we show a fast and accurate numerical method for simulating the microwave heating of moving objects, which is still a challenge because of its complicated mathematical model simultaneously coupling electromagnetic field, thermal field, and temperature-dependent moving objects. By contrast with most discrete methods whose dielectric parameters of the heated samples are updated only when they move to a new position or even turn a circle, in our simulations a real-time procedure is added to renew the parameters during the whole heating process. Furthermore, to avoid the mesh-mismatch induced by remeshing the moving objects, we move the cavity instead of samples. To verify the efficiency and accuracy, we compared our method with the arbitrary Lagrangian–Eulerian method, one of the most accurate methods for computing this process until now. For the same computation model, our method helps in decreasing the computing time by about 90% with almost the same accuracy. Moreover, the influence of the rotational speed on the microwave heating is systematically investigated by using this method. The results show the widely used speed in domestic microwave ovens, 5 rpm, is indeed a good choice for improving the temperature uniformity with high energy efficiency.
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12
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Abstract
Conventional microwave heating has serious problems such as non-uniform heating and low efficiency. A novel magnetron microwave sweep frequency heating method is proposed to improve microwave heating uniformity. In this method, the frequency-sweeping signal is injected into the magnetron by the injection frequency-locking technique, and the microwave sweep frequency heating of the magnetron is realized. In this paper, a complicated injection frequency locking system is given and analyzed and a multiphysics calculation model based on the finite element method for electromagnetic waves and heat transfer is established. The calculation of microwave sweep frequency heating is realized by the combination of COMSOL and MATLAB. The results show that the sweep frequency heating has an obvious superiority. An experiment is carried out to verify the simulation results. The simulation results are in agreement with the experimental data. Moreover, the effect of sweep bandwidth and sweep interval on heating uniformity is discussed.
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13
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Impact of Filled Materials on the Heating Uniformity and Safety of Microwave Heating Solid Stack Materials. Processes (Basel) 2018. [DOI: 10.3390/pr6110220] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Microwave heating of solid stack materials is common but bothered by problems of uneven heating and electric discharge phenomena. In this paper, a method introducing fluid materials with different relative permittivity is proposed to improve the heating uniformity and safety of solid stack materials. Simulations have been computed based on the finite element method (FEM) and validated by experiments. Simulation results show that the introducing of fluid materials with proper relative permittivity does improve the heating uniformity and safety. Fluid materials with the larger real part of relative permittivity could obviously lower the maximum modulus value of the electric field for about 23 times, and will lower the coefficient of variation (COV) in general, although in small ranges that it has fluctuated. Fluid materials with the larger imaginary part of relative permittivity, in a range from 0 to 0.3, can make a more efficient heating and it could lower the maximum modulus value of the electric field by 34 to 55% on the whole studied range. However, the larger imaginary part of relative permittivity will cause worse heating uniformity as the COV rises by 246.9% in the same process. The computed results are discussed and methods to reach uniform and safe heating through introducing fluid materials with proper relative permittivity are proposed.
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14
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Wu Y, Hong T, Tang Z, Zhang C. Dynamic Model for a Uniform Microwave-Assisted Continuous Flow Process of Ethyl Acetate Production. ENTROPY 2018; 20:e20040241. [PMID: 33265332 PMCID: PMC7512756 DOI: 10.3390/e20040241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 03/17/2018] [Accepted: 03/30/2018] [Indexed: 12/03/2022]
Abstract
The aim of this work is to present a model of a reaction tube with cross structures in order to improve ethyl acetate production and microwave heating uniformity. A commercial finite element software, COMSOL Multiphysics 4.3a (Newton, MA, USA), is used to build the proposed model for a BJ-22 rectangular waveguide system. Maxwell’s equations, the heat conduction equation, reaction kinetics equation and Navier-Stokes equation are combined to describe the continuous flow process. The electric field intensity, the temperature, the concentration of water, the coefficient of variation (COV) and the mean temperature at different initial velocities are compared to obtain the best flow rate. Four different initial velocities are employed to discuss the effect of flow velocity on the heating uniformity and heating efficiency. The point temperatures are measured by optical fibers to verify the simulated results. The results show the electric field intensity distributions at different initial velocities have little difference, which means the initial velocity will have the decisive influence on the heating process. At lower velocity, the COV will be smaller, which means better heating uniformity. Meanwhile, the distance between each cross structure has great influence on the heating uniformity and heating efficiency, while the angle has little. The proposed model can be applied to large-scale production of microwave-assisted ethyl acetate production.
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Affiliation(s)
- Yuanyuan Wu
- College of Information Science & Technology, Chengdu University of Technology, Chengdu 610000, China
| | - Tao Hong
- School of Electronic Information Engineering, China West Normal University, Nanchong 637002, China
- Correspondence: ; Tel.: +86-158-824-65675
| | - Zhengming Tang
- School of Electronic Information Engineering, China West Normal University, Nanchong 637002, China
| | - Chun Zhang
- College of Electronics and Information Engineering, Sichuan University, Chengdu 610065, China
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15
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Zhou Y, Zhang C, Xie T, Hong T, Zhu H, Yang Y, Liu C, Huang K. A Microwave Thermostatic Reactor for Processing Liquid Materials Based on a Heat-Exchanger. MATERIALS 2017; 10:ma10101160. [PMID: 28991195 PMCID: PMC5666966 DOI: 10.3390/ma10101160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 09/22/2017] [Accepted: 09/30/2017] [Indexed: 12/19/2022]
Abstract
Microwaves have been widely used in the treatment of different materials. However, the existing adjustable power thermostatic reactors cannot be used to analyze materials characteristics under microwave effects. In this paper, a microwave thermostatic chemical reactor for processing liquid materials is proposed, by controlling the velocity of coolant based on PLC (programmable logic controller) in different liquid under different constant electric field intensity. A nonpolar coolant (Polydimethylsiloxane), which is completely microwave transparent, is employed to cool the liquid materials. Experiments are performed to measure the liquid temperature using optical fibers, the results show that the precision of temperature control is at the range of ±0.5 °C. Compared with the adjustable power thermostatic control system, the effect of electric field changes on material properties are avoided and it also can be used to detect the properties of liquid materials and special microwave effects.
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Affiliation(s)
- Yongqiang Zhou
- College of Electronic and Information Engineering, Sichuan University, Chengdu 610065, China.
| | - Chun Zhang
- College of Electronic and Information Engineering, Sichuan University, Chengdu 610065, China.
| | - Tian Xie
- State Key Laboratory of Efficient Utilization for Low Grade Phosphate Rock and Its Associated Resources, Wengfu Group, Guiyang 550014, China.
| | - Tao Hong
- School of Electronic Information Engineering, China West Normal University, Nanchong 637002, China.
| | - Huacheng Zhu
- College of Electronic and Information Engineering, Sichuan University, Chengdu 610065, China.
| | - Yang Yang
- College of Electronic and Information Engineering, Sichuan University, Chengdu 610065, China.
| | - Changjun Liu
- College of Electronic and Information Engineering, Sichuan University, Chengdu 610065, China.
| | - Kama Huang
- College of Electronic and Information Engineering, Sichuan University, Chengdu 610065, China.
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