The Experts below are selected from a list of 3498 Experts worldwide ranked by ideXlab platform
Shunse Wang - One of the best experts on this subject based on the ideXlab platform.
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exergoeconomic analysis and optimization of a combined supercritical carbon dioxide Recompression brayton organic flash cycle for nuclear power plants
Energy Conversion and Management, 2018Co-Authors: Shunse WangAbstract:Abstract A novel combined supercritical carbon dioxide Recompression Brayton/organic flash cycle is investigated by means of exergoeconomic analysis. The supercritical carbon dioxide Recompression Brayton/organic flash cycle is a combination of a supercritical carbon dioxide Recompression Brayton cycle and an organic flash cycle where the organic flash cycle absorbs waste heat from the supercritical carbon dioxide Recompression Brayton cycle for power generation. Seven different organic flash cycle working fluids are examined, including n-Nonane, n-Octane, n-Heptane, n-Hexane, n-Pentane, R365mfc and R245fa. Parametric study is employed to investigate the effects of the some decision variables on the first and second law efficiencies and the total product unit cost of the supercritical carbon dioxide Recompression Brayton/organic flash cycle and the supercritical carbon dioxide Recompression Brayton cycle. The performances of the supercritical carbon dioxide Recompression Brayton/organic flash cycle and the supercritical carbon dioxide Recompression Brayton cycle are optimized and then compared from the perspective of thermodynamics and exergoeconomics. The results show that the second law efficiency and the total product unit cost of the supercritical carbon dioxide Recompression Brayton/organic flash cycle are up to 6.57% higher and up to 3.75% lower than those of the supercritical carbon dioxide Recompression Brayton cycle, respectively. Compared with the supercritical carbon dioxide Recompression Brayton/organic Rankine cycle, the supercritical carbon dioxide Recompression Brayton/organic flash cycle can obtain slightly higher second law efficiency, and comparable or slightly lower total product unit cost. It can also be concluded that the highest second law efficiency and the lowest total product unit cost for the supercritical carbon dioxide Recompression Brayton/organic flash cycle are achieved when the n-Nonane is used as the organic flash cycle working fluid.
Yilei Chen - One of the best experts on this subject based on the ideXlab platform.
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detecting Recompression of jpeg images via periodicity analysis of compression artifacts for tampering detection
IEEE Transactions on Information Forensics and Security, 2011Co-Authors: Yilei ChenAbstract:Due to the popularity of JPEG as an image compression standard, the ability to detect tampering in JPEG images has become increasingly important. Tampering of compressed images often involves Recompression and tends to erase traces of tampering found in uncompressed images. In this paper, we present a new technique to discover traces caused by Recompression. We assume all source images are in JPEG format and propose to formulate the periodic characteristics of JPEG images both in spatial and transform domains. Using theoretical analysis, we design a robust detection approach which is able to detect either block-aligned or misaligned Recompression. Experimental results demonstrate the validity and effectiveness of the proposed approach, and also show it outperforms existing methods.
Satyaki Ray - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic modelling of a Recompression co2 power cycle for low temperature waste heat recovery
Applied Thermal Engineering, 2016Co-Authors: Shubham Anik, Satyaki RayAbstract:Abstract Due to the rising prices of conventional fossil fuels, increasing the overall thermal efficiency of a power plant is essential. One way of doing this is waste heat recovery. This recovery is most difficult for low temperature waste heat, below 240 °C, which also covers majority of the waste heat source. Carbon dioxide, with its low critical temperature and pressure, offers an advantage over ozone-depleting refrigerants used in Organic Rankine Cycles (ORCs) and hence is most suitable for the purpose. This paper introduces parametric optimization of a transcritical carbon dioxide (T-CO 2 ) power cycle which recompresses part of the total mass flow of working fluid before entering the precooler, thereby showing potential for higher cycle efficiency. Thermodynamic model for a Recompression T-CO 2 power cycle has been developed with waste heat source of 2000 kW and at a temperature of 200 °C. Results obtained from this model are analysed to estimate effects on energetic and exergetic performances of the power cycle with varying pressure and mass Recompression ratio. Higher pressure ratio always improves thermodynamic performance of the cycle – both energetic and exergetic. Higher Recompression ratio also increases exergetic efficiency of the cycle. However, it increases energy efficiency, only if precooler inlet temperature remains constant. Maximum thermal efficiency of the T-CO 2 cycle with a Recompression ratio of 0.26 has been found to be 13.6%. To minimize total irreversibility of the cycle, an optimum ratio of 0.48 was found to be suitable.
Shengming Liao - One of the best experts on this subject based on the ideXlab platform.
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multi objective optimization of supercritical carbon dioxide Recompression brayton cycle considering printed circuit recuperator design
Energy Conversion and Management, 2019Co-Authors: Kaixin Huang, Shengming LiaoAbstract:Abstract Supercritical carbon dioxide Recompression Brayton cycle is well suited to a broad range of applications including nuclear and concentrated solar energy. As printed circuit recuperators are employed to optimize the thermal performance of the cycle, the recuperator optimal design is required with the objective of maximizing the cycle thermal efficiency and minimizing the total cycle cost. In this paper, a thermo-economic model of Recompression Brayton cycle with the S-shaped fin printed circuit recuperator is developed to perform multi-objective optimization considering the recuperator design parameters (i.e. mass fluxes and enthalpy efficiencies of recuperators and Recompression fraction). Nondominated sorting genetic algorithm is used to obtain Pareto frontier. The results show that compared to the mass fluxes, the enthalpy efficiencies of recuperators and Recompression fraction play more important roles in the optimization. From the Pareto frontier, the optimum range of the cycle thermal efficiency is 0.4303–0.5380 and that of the total cycle cost is 7.468 M$–12.31 M$. As high cycle thermal efficiency is preferred, the high Recompression fraction, high mass flux and high enthalpy efficiency of low temperature recuperator, low mass flux and high enthalpy efficiency of high temperature recuperator are required. In contrast, as low cycle cost is preferred, the opposite selections of design parameters are required.
Shubham Anik - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic modelling of a Recompression co2 power cycle for low temperature waste heat recovery
Applied Thermal Engineering, 2016Co-Authors: Shubham Anik, Satyaki RayAbstract:Abstract Due to the rising prices of conventional fossil fuels, increasing the overall thermal efficiency of a power plant is essential. One way of doing this is waste heat recovery. This recovery is most difficult for low temperature waste heat, below 240 °C, which also covers majority of the waste heat source. Carbon dioxide, with its low critical temperature and pressure, offers an advantage over ozone-depleting refrigerants used in Organic Rankine Cycles (ORCs) and hence is most suitable for the purpose. This paper introduces parametric optimization of a transcritical carbon dioxide (T-CO 2 ) power cycle which recompresses part of the total mass flow of working fluid before entering the precooler, thereby showing potential for higher cycle efficiency. Thermodynamic model for a Recompression T-CO 2 power cycle has been developed with waste heat source of 2000 kW and at a temperature of 200 °C. Results obtained from this model are analysed to estimate effects on energetic and exergetic performances of the power cycle with varying pressure and mass Recompression ratio. Higher pressure ratio always improves thermodynamic performance of the cycle – both energetic and exergetic. Higher Recompression ratio also increases exergetic efficiency of the cycle. However, it increases energy efficiency, only if precooler inlet temperature remains constant. Maximum thermal efficiency of the T-CO 2 cycle with a Recompression ratio of 0.26 has been found to be 13.6%. To minimize total irreversibility of the cycle, an optimum ratio of 0.48 was found to be suitable.
