The Molten Salt Reactor （MSR）, one of the ‘Generation Ⅳ＇ concepts, is a liquid-fuel reactor, which is different from the conventional reactors using solid fissile materials due to the flow effect of fuel salt. Th...
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The Molten Salt Reactor （MSR）, one of the ‘Generation Ⅳ＇ concepts, is a liquid-fuel reactor, which is different from the conventional reactors using solid fissile materials due to the flow effect of fuel salt. The study on its neutronics considering the fuel salt flow, which is the base of the thermal-hydraulic calculation and safety analysis, must be done. In this paper, the theoretical model on neutronics under steady condition for a single-liquid-fueled MSR is conducted and calculated by numerical method. The neutronics model consists of two group neutron diffusion equations for fast and thermal neutron fluxes, and balance equations for six-group delayed neutron precursors considering the flow effect of fuel salt. The spatial discretization of the above models is based on the finite volume method, and the discretization equations are computed by the source iteration method. The distributions of neutron fluxes and the distributions of the delayed neutron precursors in the core are obtained. The numerical calculated results show that, the fuel salt flow has little effect on the distribution of fast and thermal neutron fluxes and the effective multiplication factor; however, it affects the distribution of the delayed neutron precursors significantly, especially the long-lived one. In addition, it could be found that the delayed neutron precursors influence the neutronics slightly under the steady condition.
Local hydrodynamics in the riser of an external loop airlift reactor （EL-ALR） are identified and the performances of three drag models are evaluated in computational fluid dynamics simulation. The simulation results...
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Local hydrodynamics in the riser of an external loop airlift reactor （EL-ALR） are identified and the performances of three drag models are evaluated in computational fluid dynamics simulation. The simulation results show that the Schiller-Naumann drag model underestimated the local gas holdup at lower superficial gas velocity whereas the Tomiyama drag model overestimated that at higher superficial gas velocity. By contrast, the dual-bubble-size （DBS）-local drag model gave more reasonable radial and axial distri-butions of gas holdup in all cases. The reason is that the DBS-local drag model gave correct values of the lumped parameter, i,e., the ratio of the drag coefficient to bubble diameter, for varying operating conditions and radial positions. This ratio is reasonably expected to decrease with increasing superficial gas velocity and be smaller in the center and larger near the wall. Only the DBS-local drag model correctly reproduced these trends. The radial profiles of the axial velocity of the liquid and gas predicted by the DBS-local model also agreed well with experimental data.
The laminar flame speeds of ammonia mixed with syngas at a high pressure, temperature, and different syngas ratios were measured. The data obtained were fitted at different pressures, temperatures, syngas ratios, and ...
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The laminar flame speeds of ammonia mixed with syngas at a high pressure, temperature, and different syngas ratios were measured. The data obtained were fitted at different pressures, temperatures, syngas ratios, and equivalence ratios. Four kinetic models (the Glarborg model, Shrestha model, Mei model, and Han model) were compared and validated with experimental data. Pathway, sensitivity and radical pool analysis are conducted to find out the deep kinetic insight on ammonia oxidation and NO formation. The pathway analysis shows that H abstraction reactions and NHi combination reactions play important roles in ammonia oxidation. NO formation is closely related to H, OH, the O radical produced, and formation reactions. NO is mainly formed from reaction, HNO+ H= NO+ H2. Furthermore, both ammonia oxidation and NO formation are sensitive to small radical reactions and ammonia related reactions.
Oxygen evolving catalyst (OEC) is a critical determinant for the efficiency of photoelectrochemical (PEC) water splitting. Here we report an approach to depositing a novel manganese borate (Mn-Bi) OER catalyst on BiVO...
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Oxygen evolving catalyst (OEC) is a critical determinant for the efficiency of photoelectrochemical (PEC) water splitting. Here we report an approach to depositing a novel manganese borate (Mn-Bi) OER catalyst on BiVO4 nanocone photoanode by photodeposition in sodium borate buffer solution containing Mn(Ⅱ) ions. Due to the spontaneous photo-electric-field-enhancement effect at the vertically oriented BiVO4 nanocone structure, spherical Mn-Bi nanoparticle was selectively photodeposited at the apex of BiVO4 nanocone. Significant improvement of photocurrent was observed for the obtained hierarchical Mn-Bi/BiVO4 photoanode which could be ascribed to enhanced hole injection efficiency, especially in low bias region. It was observed that the injection efficiency of Mn-Bi/BiVO4 is 98% which gave a photocurrent of 0.94 mA/cm^2 at 1.5 V vs. RHE.
Photoelectrochemical(PEC)water splitting using semiconductors offers a promising way to convert renewable solar energy to clean hydrogen ***,due to the sluggish reaction kinetics of water oxidation,significant charge ...
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Photoelectrochemical(PEC)water splitting using semiconductors offers a promising way to convert renewable solar energy to clean hydrogen ***,due to the sluggish reaction kinetics of water oxidation,significant charge recombination occurred at the photoanode/electrolyte interface and cause decrease of its PEC *** reduce the surface recombination,we deposit different transition metal complexes on BiVO4 nanocone arrays by a versatile light driven in-situ two electrode photodeposition approach without applied *** cobalt phosphate“Co-Pi”,nickel borate“Ni-Bi”and manganese phosphate“Mn-Pi”complexes were deposited on BiVO4 nanocone arrays to form core-shell structure photoanode,all of which lead to enhanced photoelectrochemical *** photocurrent of the Co-Pi/BiVO4 photoanode under front-side illumination for 5 min is increased by 4 folds comparing to that of bare BiVO4 photoanode at 0.6 V ***,reaching a hole transfer efficiency as high as 94.5%at 1.23 V *** proposed photodeposition strategy is simple and efficient,and can be extended to deposite cocatalyst on other semiconductors with a valence band edge located at a potential more positive than the oxidation potential of transition metal ion in the cocatalyst.
Nano-confined binary mixtures are prevalent in the chemical industry, geology, and energy sectors. Investigating their mass transfer behavior can enhance process intensification. This study examines the confined self-...
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Nano-confined binary mixtures are prevalent in the chemical industry, geology, and energy sectors. Investigating their mass transfer behavior can enhance process intensification. This study examines the confined self-diffusion coefficients of binary mixtures of supercritical water (SCW) with H 2 , CO, CO 2 and CH 4 in carbon nanotubes (CNT) using molecular dynamics (MD) simulations at temperatures of 673-973 K, a pressure of 25-28 MPa, solute molar concentrations of 0.01.0.3, and CNT diameters of 9.49-29.83 Å. We developed a novel machine learning (ML) clustering method to optimize abnormal MSD- t data, effectively extracting information and providing algorithmic enhancements for calculating the diffusion coefficient. We analyzed the effects of temperature, solute molar concentration, and CNT diameter on the confined self-diffusion coefficient and energy input. Results indicate that over 60 % of the solute energy input derives from the Lennard-Jones effect of the CNT wall. The confined self-diffusion coefficient of solutes increases linearly with temperature, saturates with increasing CNT diameter, and remains relatively constant with varying concentration. Finally, based on the unique relationship between CNTs and the confined self-diffusion coefficient, we developed a new mathematical model for prediction. The regression line exhibits an R 2 value of 0.9789, offering a new method for predicting the properties of nano-confined fluids.
Obtaining an accurate temperature distribution in furnaces for industrial combustion devices is critical. Acoustic pyrometry (AP) is a promising methodology for high-quality temperature field reconstruction, which is ...
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Obtaining an accurate temperature distribution in furnaces for industrial combustion devices is critical. Acoustic pyrometry (AP) is a promising methodology for high-quality temperature field reconstruction, which is widely used in the monitoring of atmosphere, room, and furnace. However, due to the harsh working environment and the engineering limitations, the number of installed acoustic transducers is restricted, which in turn results in sparse valid data and an ill-posed AP problem. We used multiple means of improvement to improve the reconstruction performance of AP in a gradual and systematic manner. The fast finite-difference shooting method, the adaptive grid evolution strategy (AGES) and the radial basis function approximation with polynomial reproduction (RBFPR) were proposed and integrated into the sequential process optimization approach we concluded to systematically improve the reconstruction performance over the initial algorithm. In this approach, we optimized the parameters used for the reconstruction sequentially, analyzed the effectiveness of various means of improvement, finalized and validated an algorithm that takes into account universality and precision. Qualitative and quantitative analyses of the simulation and experimental results show the validity of the finalized algorithm and the sequential process optimization approach, demonstrating its significance for furnace temperature field measurement, combustion control, and environmental protection.
The segregated algorithm-IDEAL (inner doubly-iterative efficient algorithm for linked-equations) is an efficient and stable algorithm. In this algorithm, there exist inner doubly-iterative processes for pres-sure equa...
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The segregated algorithm-IDEAL (inner doubly-iterative efficient algorithm for linked-equations) is an efficient and stable algorithm. In this algorithm, there exist inner doubly-iterative processes for pres-sure equation, which almost completely overcome two approximations in SIMPLE algorithm. Thus the coupling between velocity and pressure is fully guaranteed, greatly enhancing the convergence rate and stability of iteration process. In this paper, implementation of the IDEAL algorithm on a 3D collo-cated grid system is conducted. The interface velocity is calculated by the modified momentum inter-polation method (MMIM), by which the converged result is independent of the under-relaxation factor. Finally, five three-dimensional incompressible fluid flow and heat transfer problems are provided to compare the convergence rate and robustness between the IDEAL and three other most widely-used algorithms (SIMPLER, SIMPLEC and PISO). By the comparison it can be concluded that the IDEAL al-gorithm is more robust and efficient than the three other algorithms.
With continuous research on photocatalytic water splitting, searching for efficient catalyst for hydrogen evolution reaction(HER) becomes popular topic in addition to main catalyst research. Transition metal phosphide...
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With continuous research on photocatalytic water splitting, searching for efficient catalyst for hydrogen evolution reaction(HER) becomes popular topic in addition to main catalyst research. Transition metal phosphides are receiving intense attention due to its abundance in the Earth's crust and comparable catalytic properties to noble metals. In this review, the synthesis approaches, HER reaction mechanism,photocatalytic activity, approaches to improve the activity of transition metal phosphides were reviewed and discussed. It was showed that the transition metal phosphides have great potential to reduce the cost of photocatalyst and promising application on water splitting. The stability problem and participation of poisonous reactant and product in its synthesis reaction limit its application and developing in a certain extent, but with the continuous efforts on the development and improvement of the synthesis methods,transition metal phosphides will find wide application in water splitting.
The vapor-liquid self-adjusting controller is an innovative automatic regulating *** order to ensure adjusted objects run safely and economically,the controller automatically adjusts the liquid flux to keep liquid lev...
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The vapor-liquid self-adjusting controller is an innovative automatic regulating *** order to ensure adjusted objects run safely and economically,the controller automatically adjusts the liquid flux to keep liquid level at a required level according to physical properties of vapor-liquid two-phase *** adjusting mechanics,the controller’s performance and influencing factors of its stability have been analyzed in this *** theoretical analysis and successful applications have demonstrated this controller can keep the liquid level steady with good *** actual application in industry has shown that the controller can satisfactorily meet the requirement of industrial production and has wide application areas.
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