The Experts below are selected from a list of 163173 Experts worldwide ranked by ideXlab platform
Noemi E Zaritzky - One of the best experts on this subject based on the ideXlab platform.
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mathematical analysis of microwave Heating Process
Journal of Food Engineering, 2005Co-Authors: Laura Analia Campanone, Noemi E ZaritzkyAbstract:Abstract The use of microwaves in the food industry is attributed to the lower time needed to increase the temperature of foodstuffs compared to the traditional Heating methods. However, the Heating is not uniform and the products show hot and cold spots. In order to analyze the behavior of microwaved foods a mathematical method was developed solving the unsteady state heat transfer differential equations. The model was applied to large systems for which Lambert’s law is valid because it leads to similar results as Maxwell equation. It takes into account variable thermal and electromagnetic properties. The numerical solution was developed using an implicit finite difference method in one dimensional systems (sphere, infinite cylinder and slab) and an alterning direction method in two- and three-dimensional conditions (finite cylinders and brick shaped products). It allows to predict temperature profiles and Heating times. The model was validated with own data of mashed potato and meat products and with experimental data from literature obtained with agar gel, sodium alginate gel and whole potato.
Zhong Han - One of the best experts on this subject based on the ideXlab platform.
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hyperspectral imaging sensing of changes in moisture content and color of beef during microwave Heating Process
Food Analytical Methods, 2018Co-Authors: Yuwei Liu, Dawen Sun, Junhu Cheng, Zhong HanAbstract:Moisture content (MC) and color are two important quality parameters of beef during microwave Heating Process. This study examined the effects of microwave Heating time (0–75 s) on MC, color, and myoglobins of beef samples. The results showed that Heating time significantly influenced the MC, color (L*, a*), and percentage of related myoglobins. The suitability of hyperspectral imaging (HSI) (400–1000 nm) was investigated to correlate the mean spectra of beef samples and the color and MC values during microwave treatment. After the use of pre-Processing methods and optimum wavelengths selection, the SG-SPA-LS-SVM prediction model for MC (R2P = 0.869, RMSEP = 1.304, and RPD = 2.724) and the SG-RC-MLR model for a* (R2P = 0.890, RMSEP = 0.735, and RPD = 2.733) were established. The models were then used to develop the distribution maps of MC and a* values, respectively, showing that both MC and a* at the center of the meat slices were higher than those at the edge, corresponding to the temperature distribution during microwave Heating. The results demonstrated the ability of HSI system for monitoring the changes of some quality parameters during microwave Heating.
Huijun Feng - One of the best experts on this subject based on the ideXlab platform.
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power efficiency power density and ecological function optimization for an irreversible modified closed variable temperature reservoir regenerative brayton cycle with one isothermal Heating Process
Energies, 2020Co-Authors: Chenqi Tang, Huijun FengAbstract:One or more isothermal Heating Process was introduced to modify single and regenerative Brayton cycles by some scholars, which effectively improved the thermal efficiency and significantly reduced the emissions. To analyze and optimize the performance of this type of Brayton cycle, a regenerative modified Brayton cycle with an isothermal Heating Process is established in this paper based on finite time thermodynamics. The isothermal pressure drop ratio is variable. The irreversibilities of the compressor, turbine and all heat exchangers are considered in the cycle, and the heat reservoirs are variable-temperature ones. The function expressions of four performance indexes; that is, dimensionless power output, thermal efficiency, dimensionless power density and dimensionless ecological function are obtained. With the dimensionless power density as the optimization objective, the heat conductance distributions among all heat exchangers and the thermal capacitance rate matching among the working fluid and heat reservoir are optimized. Based on the NSGA-II algorithm, the cycle’s double-, triple- and quadruple-objective optimization are conducted with the total pressure ratio and the heat conductance distributions among heat exchangers as design variables. The optimal value is chosen from the Pareto frontier by applying the LINMAP, TOPSIS and Shannon entropy methods. The results show that when the pressure ratio in the compressor is less than 12.0, it is beneficial to add the regenerator to improve the cycle performance; when the pressure ratio is greater than 12.0, adding the regenerator will reduce the cycle performance. For single-objective optimization, the four performance indexes could be maximized under the optimal pressure ratios, respectively. When the pressure ratio is greater than 9.2, the cycle is simplified to a closed irreversible simple modified Brayton cycle with one isothermal Heating Process and coupled to variable-temperature heat reservoirs. Therefore, when the regenerator is used, the range of pressure ratio is limited, and a suitable pressure ratio should be selected. The triple objective (dimensionless power output, dimensionless power density and dimensionless ecological function) optimization’ deviation index gained by LINMAP or TOPSIS method is the smallest. The optimization results gained in this paper could offer some new pointers for the regenerative Brayton cycles’ optimal designs.
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Power density analysis and multi-objective optimization for a modified endoreversible simple closed Brayton cycle with one isothermal Heating Process
Energy Reports, 2020Co-Authors: Chenqi Tang, Huijun Feng, Wenhua WangAbstract:Abstract By using finite time thermodynamics, a modified endoreversible simple closed Brayton cycle with one isothermal Heating Process and variable isothermal pressure drop ratio is established in this paper. The cycle is composed of a compressor, a regular combustion chamber, a converging combustion chamber, a turbine and a precooler. Three variable temperature heat reservoirs are considered. The dimensionless power density is selected as the optimization objective, and the effects of inlet temperature ratios of combustion chambers on the optimal performances are studied. The results show that adding a convergent combustion chamber to the cycle can increase the dimensionless power density by 18.57%. There exit the optimal heat conductance distributions among three heat exchangers and the optimal pressure ratio leading to maximum dimensionless power density. The Pareto front based on dimensionless power output, thermal efficiency and dimensionless power density is further obtained by applying NSGA-II algorithm, and three decision methods are employed to choose the appropriate schemes from Pareto front. The different optimization schemes gained in this paper can satisfy different design demands for practical Brayton cycle power plants.
Chenqi Tang - One of the best experts on this subject based on the ideXlab platform.
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power efficiency power density and ecological function optimization for an irreversible modified closed variable temperature reservoir regenerative brayton cycle with one isothermal Heating Process
Energies, 2020Co-Authors: Chenqi Tang, Huijun FengAbstract:One or more isothermal Heating Process was introduced to modify single and regenerative Brayton cycles by some scholars, which effectively improved the thermal efficiency and significantly reduced the emissions. To analyze and optimize the performance of this type of Brayton cycle, a regenerative modified Brayton cycle with an isothermal Heating Process is established in this paper based on finite time thermodynamics. The isothermal pressure drop ratio is variable. The irreversibilities of the compressor, turbine and all heat exchangers are considered in the cycle, and the heat reservoirs are variable-temperature ones. The function expressions of four performance indexes; that is, dimensionless power output, thermal efficiency, dimensionless power density and dimensionless ecological function are obtained. With the dimensionless power density as the optimization objective, the heat conductance distributions among all heat exchangers and the thermal capacitance rate matching among the working fluid and heat reservoir are optimized. Based on the NSGA-II algorithm, the cycle’s double-, triple- and quadruple-objective optimization are conducted with the total pressure ratio and the heat conductance distributions among heat exchangers as design variables. The optimal value is chosen from the Pareto frontier by applying the LINMAP, TOPSIS and Shannon entropy methods. The results show that when the pressure ratio in the compressor is less than 12.0, it is beneficial to add the regenerator to improve the cycle performance; when the pressure ratio is greater than 12.0, adding the regenerator will reduce the cycle performance. For single-objective optimization, the four performance indexes could be maximized under the optimal pressure ratios, respectively. When the pressure ratio is greater than 9.2, the cycle is simplified to a closed irreversible simple modified Brayton cycle with one isothermal Heating Process and coupled to variable-temperature heat reservoirs. Therefore, when the regenerator is used, the range of pressure ratio is limited, and a suitable pressure ratio should be selected. The triple objective (dimensionless power output, dimensionless power density and dimensionless ecological function) optimization’ deviation index gained by LINMAP or TOPSIS method is the smallest. The optimization results gained in this paper could offer some new pointers for the regenerative Brayton cycles’ optimal designs.
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Power density analysis and multi-objective optimization for a modified endoreversible simple closed Brayton cycle with one isothermal Heating Process
Energy Reports, 2020Co-Authors: Chenqi Tang, Huijun Feng, Wenhua WangAbstract:Abstract By using finite time thermodynamics, a modified endoreversible simple closed Brayton cycle with one isothermal Heating Process and variable isothermal pressure drop ratio is established in this paper. The cycle is composed of a compressor, a regular combustion chamber, a converging combustion chamber, a turbine and a precooler. Three variable temperature heat reservoirs are considered. The dimensionless power density is selected as the optimization objective, and the effects of inlet temperature ratios of combustion chambers on the optimal performances are studied. The results show that adding a convergent combustion chamber to the cycle can increase the dimensionless power density by 18.57%. There exit the optimal heat conductance distributions among three heat exchangers and the optimal pressure ratio leading to maximum dimensionless power density. The Pareto front based on dimensionless power output, thermal efficiency and dimensionless power density is further obtained by applying NSGA-II algorithm, and three decision methods are employed to choose the appropriate schemes from Pareto front. The different optimization schemes gained in this paper can satisfy different design demands for practical Brayton cycle power plants.
Zhang Shimin - One of the best experts on this subject based on the ideXlab platform.
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microwave energy Heating Process for cycling fluid medium based on apso pid control strategy
Energy Procedia, 2012Co-Authors: Yang Biao, Li Wei, Peng Jinhui, Guo Shenghui, Zhang ShiminAbstract:Abstract The higher power microwave Heating source, in the industrial and engineering needs, is obtained through inputting microwave energy of multi-open feed into cavity via near-field radiation, resulting in the coupling of each feed. Meanwhile, the initial situation, the ratio of fluid and the permittivity are highly nonlinear in the Process of microwave Heating during technical operation Process by microwave Heating Process cycling fluid medium. This paper is presented an improved Anti-predatory Particle Swarm Optimization (APSO) algorithm to optimize the three parameters of PID controller, and is applied to control the complicated and coupling of microwave Heating. It is shown through intelligent calculation and simulation experiments that the improved APSO has good performance. And this paper provides an alternative for control of multi-couple and uncertain objects in industry.