The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
A. A. Shipkov - One of the best experts on this subject based on the ideXlab platform.
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A Combined Binary-Cycle Geothermal Power Plant with a Secondary Flash Steam Superheating System: Choice of Optimal Working Fluids
Thermal Engineering, 2019Co-Authors: G. V. Tomarov, A. A. ShipkovAbstract:—The article presents the results from numerically modeling the process circuit of a combined binary-cycle double-flash geothermal power plant (GeoPPs) with the use of secondary flash Steam superheating by means of a hydrogen–oxygen Steam generator. Geothermal heat carrier from substandard wells of the Mutnovsk geothermal field, as well as Separated Steam and waste brine from the Mutnovsk GeoPP, were taken as the primary heat source. Numerical investigation results have shown that the application of secondary flash Steam superheating by means of a hydrogen–oxygen Steam generator makes it possible to increase the Steam turbine’s power output and its flow path efficiency owing to the Steam wetness reduced by more than a factor of two. In addition, reduced Steam wetness helps prevent erosion damage to the last-stage turbine rotor blades. Data on the effect that the use of different organic substances has on the efficiency and power output of the binary installation and of the GeoPP as a whole are given. Optimization investigations have shown that the highest power output and efficiency values of the binary installation used as part of a combined binary-cycle GeoPP at the lowest specific brine flowrate are achieved in using organic substances from the groups of nontoxic fire- and flame-proof (R-31-10 and RC-318) and low-toxic fire- and flame-proof ones (R-227ea, R-236fa, R1318, and R-134a) as working fluids. It has been established that the highest power output values of a combined binary-cycle double-flash GeoPP with secondary flash Steam superheating by means of a hydrogen–oxygen Steam generator are achieved in using the organic working fluids R-31-10, R‑227ea, and RC-318. In so doing, the optimum design pressure in the expander-separator at which the highest efficiency and power output of the studied GeoPP are obtained makes 0.47 MPa. In solving optimization problems on selecting the working fluids for binary combined-cycle GeoPP installations, it is proposed to use multiaxial composite diagrams of the relative values of geothermal power plant parameters and characteristics. An example of drawing a multiaxial composite diagram for the relative values of parameters and characteristics for a combined binary-cycle GeoPP for the R-290, R-31-10, R-32, and RC-318 working fluids is given. The numerical investigation results can be used in designing new and modernizing the operating GeoPPs that use Steam geothermal sources.
Junjie Yan - One of the best experts on this subject based on the ideXlab platform.
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pressure oscillation and Steam cavity during the condensation of a submerged Steam jet
Annals of Nuclear Energy, 2015Co-Authors: Quanbin Zhao, Wei Wang, Weixiong Chen, Fang Yuan, Daotong Chong, Junjie YanAbstract:Abstract Steam jet condensation is important in many industrial applications. In this work, the pressure oscillation and Steam jet patterns during submerged jet condensation in quiescent water is investigated experimentally. Firstly, it is found that even at stable condensation region, the Steam cavity length varies all the time and Steam bubbles separate from the Steam cavity periodically. With the variation of Steam cavity length and Separated bubble oscillation, condensation also undergoes oscillation. Along the axial direction, the pressure oscillation intensity increases first and then decreases gradually. There is an distinct pressure oscillation peak, and the peak position varies over a length-to-diameter ratio range of X / D = 2 to X / D = 7. The axial position of pressure oscillation peak corresponds to the end of Steam cavity. Moreover, oscillation energy analysis shows that the oscillation energy generated by Separated Steam bubble is much higher than that generated by the Steam cavity length variation. Finally, based on the relationship between the axial distribution of pressure oscillation and the Steam cavity, a method is proposed to determine the maximum Steam cavity length by measuring the pressure oscillation distributions. The predicted deviation is only in range of ±16% for the test conditions.
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Experimental and theoretical study on the second dominant frequency in submerged Steam jet condensation
Experimental Thermal and Fluid Science, 2015Co-Authors: Daotong Chong, Quanbin Zhao, Weixiong Chen, Fang Yuan, Yuelei Cong, Junjie YanAbstract:Abstract Condensation oscillation of Steam jet is of high importance for industrial facility. In this study, the mechanism and propagation characteristic of the second dominant frequency is investigated. Firstly, the second dominant frequency is found under all the test conditions based on frequency spectrum. The second dominant frequency decreases with the rise of water temperature and Steam mass flux. Then, the second dominant frequency is proved to be generated by the Separated Steam bubbles oscillation based on the bubble oscillation theory. And the theoretical oscillation frequency equation of Separated Steam bubble is used to predict the second dominant frequency, the predicted deviation ranges from −17% to 6%. Furthermore, the propagation characteristic of the second dominant frequency is investigated, and a theoretical propagation equation for the second dominant frequency is derived. Then, the axial and radial distribution characteristic of oscillation amplitude and energy of the second dominant frequency are analyzed and researched. In the downstream flow field and the radial direction, the propagation characteristic of Steam bubble oscillation wave is well corresponding to the predicted results. However, in the upstream flow field, due to the effect of Steam plume, the oscillation amplitude and energy of the second dominant frequency attenuate rapidly and the experimental data are much smaller than the predicted value.
G. V. Tomarov - One of the best experts on this subject based on the ideXlab platform.
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A Combined Binary-Cycle Geothermal Power Plant with a Secondary Flash Steam Superheating System: Choice of Optimal Working Fluids
Thermal Engineering, 2019Co-Authors: G. V. Tomarov, A. A. ShipkovAbstract:—The article presents the results from numerically modeling the process circuit of a combined binary-cycle double-flash geothermal power plant (GeoPPs) with the use of secondary flash Steam superheating by means of a hydrogen–oxygen Steam generator. Geothermal heat carrier from substandard wells of the Mutnovsk geothermal field, as well as Separated Steam and waste brine from the Mutnovsk GeoPP, were taken as the primary heat source. Numerical investigation results have shown that the application of secondary flash Steam superheating by means of a hydrogen–oxygen Steam generator makes it possible to increase the Steam turbine’s power output and its flow path efficiency owing to the Steam wetness reduced by more than a factor of two. In addition, reduced Steam wetness helps prevent erosion damage to the last-stage turbine rotor blades. Data on the effect that the use of different organic substances has on the efficiency and power output of the binary installation and of the GeoPP as a whole are given. Optimization investigations have shown that the highest power output and efficiency values of the binary installation used as part of a combined binary-cycle GeoPP at the lowest specific brine flowrate are achieved in using organic substances from the groups of nontoxic fire- and flame-proof (R-31-10 and RC-318) and low-toxic fire- and flame-proof ones (R-227ea, R-236fa, R1318, and R-134a) as working fluids. It has been established that the highest power output values of a combined binary-cycle double-flash GeoPP with secondary flash Steam superheating by means of a hydrogen–oxygen Steam generator are achieved in using the organic working fluids R-31-10, R‑227ea, and RC-318. In so doing, the optimum design pressure in the expander-separator at which the highest efficiency and power output of the studied GeoPP are obtained makes 0.47 MPa. In solving optimization problems on selecting the working fluids for binary combined-cycle GeoPP installations, it is proposed to use multiaxial composite diagrams of the relative values of geothermal power plant parameters and characteristics. An example of drawing a multiaxial composite diagram for the relative values of parameters and characteristics for a combined binary-cycle GeoPP for the R-290, R-31-10, R-32, and RC-318 working fluids is given. The numerical investigation results can be used in designing new and modernizing the operating GeoPPs that use Steam geothermal sources.
M. Mozaffarian - One of the best experts on this subject based on the ideXlab platform.
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Advanced fuel cell energy conversion systems
Energy Conversion and Management, 1997Co-Authors: Daniela Jansen, M. MozaffarianAbstract:As part of ECN's in-house R&D programme on molten carbonate (fuel cells (MCFC), assessment studies for small systems (500 kWe) in decentralised applications, e.g. commercial and industrial combined heat and power (CHP) and for large systems (600 MWe) in centralised power generation applications have been performed. For a 500 kWeinternal reforming MCFC CHP plant, different system designs are evaluated with respect to the possibilities for production of process heat at different temperature levels. This includes the calculations of the electrical and thermal efficiencies and estimations of the investment costs. System designs are characterised by the operating pressure and method of Steam handling (anode gas recycling or Separated Steam injection). To determine the future market potential or coal-fuelled MCFC power plants, the promise of this fuel cell technology was assested against the performance and development of the competing technologies normally used for these applications. Coal-fuelled fuel cell power plants wilt have to face severe competition from advanced pulverised coal and integrated gasification combined cycle (IGCC) power plants, despite their higher electrical efficiency.
Daotong Chong - One of the best experts on this subject based on the ideXlab platform.
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pressure oscillation and Steam cavity during the condensation of a submerged Steam jet
Annals of Nuclear Energy, 2015Co-Authors: Quanbin Zhao, Wei Wang, Weixiong Chen, Fang Yuan, Daotong Chong, Junjie YanAbstract:Abstract Steam jet condensation is important in many industrial applications. In this work, the pressure oscillation and Steam jet patterns during submerged jet condensation in quiescent water is investigated experimentally. Firstly, it is found that even at stable condensation region, the Steam cavity length varies all the time and Steam bubbles separate from the Steam cavity periodically. With the variation of Steam cavity length and Separated bubble oscillation, condensation also undergoes oscillation. Along the axial direction, the pressure oscillation intensity increases first and then decreases gradually. There is an distinct pressure oscillation peak, and the peak position varies over a length-to-diameter ratio range of X / D = 2 to X / D = 7. The axial position of pressure oscillation peak corresponds to the end of Steam cavity. Moreover, oscillation energy analysis shows that the oscillation energy generated by Separated Steam bubble is much higher than that generated by the Steam cavity length variation. Finally, based on the relationship between the axial distribution of pressure oscillation and the Steam cavity, a method is proposed to determine the maximum Steam cavity length by measuring the pressure oscillation distributions. The predicted deviation is only in range of ±16% for the test conditions.
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Experimental and theoretical study on the second dominant frequency in submerged Steam jet condensation
Experimental Thermal and Fluid Science, 2015Co-Authors: Daotong Chong, Quanbin Zhao, Weixiong Chen, Fang Yuan, Yuelei Cong, Junjie YanAbstract:Abstract Condensation oscillation of Steam jet is of high importance for industrial facility. In this study, the mechanism and propagation characteristic of the second dominant frequency is investigated. Firstly, the second dominant frequency is found under all the test conditions based on frequency spectrum. The second dominant frequency decreases with the rise of water temperature and Steam mass flux. Then, the second dominant frequency is proved to be generated by the Separated Steam bubbles oscillation based on the bubble oscillation theory. And the theoretical oscillation frequency equation of Separated Steam bubble is used to predict the second dominant frequency, the predicted deviation ranges from −17% to 6%. Furthermore, the propagation characteristic of the second dominant frequency is investigated, and a theoretical propagation equation for the second dominant frequency is derived. Then, the axial and radial distribution characteristic of oscillation amplitude and energy of the second dominant frequency are analyzed and researched. In the downstream flow field and the radial direction, the propagation characteristic of Steam bubble oscillation wave is well corresponding to the predicted results. However, in the upstream flow field, due to the effect of Steam plume, the oscillation amplitude and energy of the second dominant frequency attenuate rapidly and the experimental data are much smaller than the predicted value.
