In this paper a dynamic model of transcritical CO2 ejector expansion refrigeration cycle with two-stage evaporation (EERC-TE) is established to track the transient response of system parameter at two regulation method...
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ISBN:
(纸本)9782362150128
In this paper a dynamic model of transcritical CO2 ejector expansion refrigeration cycle with two-stage evaporation (EERC-TE) is established to track the transient response of system parameter at two regulation methods which includes the vapour quality adjustment and the entrainment ratio adjustment. The effectiveness of system model is verified and the results show the predictions have a agreement with the experimental data. Based on the unit change of ejector nozzle throat area and volume flow rate of chilled water of the second evaporator, the dynamic responses of pressure in gas cooler, the first and second evaporator, mass flow rate of primary flow, entrainment ratio and vapour quality of separator inlet are compared. The regulation of ejector nozzle throat area causes relatively large system responses compared to that of chilled water flow rate of the second evaporator. This work is useful to guide system control and the improvement of system performance.
Two-phase flashing spray holds a special interest in the safety area. High pressure liquids or liquefied gases accidentally released from small hole in chemical or nuclear industry can form two-phase mixtures due to t...
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A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an eth...
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A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and 1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques, including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichlorometh- ane with an efficiency of 〉96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.
A two-way coupling three-dimensional Vortex-In-Cell (VIC) method is developed for the simulation of gas-solid turbulent flow. The evolution of vortex elements and the motion of solid particles are tracked in the Lagra...
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A two-way coupling three-dimensional Vortex-In-Cell (VIC) method is developed for the simulation of gas-solid turbulent flow. The evolution of vortex elements and the motion of solid particles are tracked in the Lagrangian frame, while the flow field is solved by the vorticity Poisson equation on the Eulerian grid. Two-way coupling is implemented by introducing a vorticity source term induced by the motion of particle. This method is applied to simulate the particulate jet generated by solid particles falling from a circular orifice into unbounded quiescent air. The simulation results agree well with the experiment conducted by Ogata, which confirmed the validation of this method. The simulation results demonstrate that the air velocity radial distribution due to the particulate jet satisfies Gaussian distribution. The particle flow rate has little influence on the spread of particles, while velocity of particles increases with increasing the particle flow rate.
Recently, MAAP and MELCOR research teams completed a set of accident simulations to reconstruct the Fukushima-Daiichi accident in order to better understand severe accident progression. One result from this work was t...
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In this study, the relevant thermal-hydraulic, mechanic-material and burnup effect calculation models were established. On the basis of these mathematic and physic models, a thermal- mechanic-material coupling analysi...
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ISBN:
(纸本)9781510811843
In this study, the relevant thermal-hydraulic, mechanic-material and burnup effect calculation models were established. On the basis of these mathematic and physic models, a thermal- mechanic-material coupling analysis code for a dispersion-plate-type fuel assembly was independently developed with the consideration of the burnup effects. The coupling program was applied to perform the thermal-mechanical-material behavior analysis of a dispersion-plate-type fuel assembly. Major physical parameters at different burnup stages were well predicted, including flux distribution, temperature profile, Mises stress and mechanic deformations. The result shows that geometric sizes of flow channels are the key parameters determining the coolant flux distribution and the temperature profile of the edge plate presents substantial asymmetry as a result of asymmetric heat transfer caused by the asymmetric geometry. Furthermore, the equivalent stress of base material increased rapidly with burnup because of the thermal expansion and burnup effects, which resulted in substantial plastic deformation and mechanical damage. In addition, the mechanism and process of blistering was investigated for blistering prediction. The result shows that due to the increasing fission gas pressure and the deteriorating yield stress of the cladding, fuel plate blistering may happen when the burnup depth up to a certain value and fuel plate will finally fall into failure as a result of over plastic deformation.
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