Temperature Effects on Concentration Polarization Thickness in Thin‐Film Composite Reverse Osmosis Membranes

Continuous research and development of reverse osmosis (RO) technologies has led to the production of membranes that are very effective with high salt rejection abilities. As temperature is one of the factors that affects salt rejection capabilities in membranes, this paper investigates the effect of temperature on the thickness of the concentration polarization layer (CPL) deposited on thin‐film composite seawater RO membranes. Two types of membranes were studied: those with ex situ macromolecules and those with in situ macromolecules. FilmTec's reverse osmosis system analysis design software was used to predict the variation of salt rejection and permeate flow rate with temperature. The impact of these variations on the thickness of the CPL was analyzed for different polyamide concentrations in the membrane.     

Economic Analysis Between Diesel and SOFC Electricity via Fusion-Biomass Hybrid Model

The fusion-biomass hybrid model system, which takes waste biomass from municipal and agricultural areas as well as forests as feedstock, produces either diesel through the Fischer–Tropsch (FT) reaction or electricity by the solid oxide fuel cell (SOFC). This system produces synthesis gas by endothermic pyrolytic gasification using high temperature fusion heat. A temperature of over 700 °C of exterior thermal heat from the fusion reactors with a duel cooled lithium lead blanket and its technical extension bring about biomass gasification to produce maximum amounts of chemical energy and synthetic gas, from feedstock. First, synthetic gas that contains hydrogen (H₂) and carbon monoxide (CO) can be converted into artificial diesel (–CH₂–), which is regarded as “carbon–neutral”. The other is to generate electricity by putting synthetic gas into SOFC at various scales, not only at the plant scale but also at the residential scale. This paper aims to conduct an economic analysis of the fusion-biomass hybrid model by comparing diesel and SOFC electricity under the assumption of the investment of a biomass plant with an FT reaction facility and one with SOFC. A sensitivity analysis is performed applying diesel price, electricity price, SOFC efficiency, diesel subsidy, and fusion heat cost. These results can help in targeting which products are economically justified in the circumstances of variable environmental policies under different policies and economic situations, which would have a significant impact on commercial fusion designing.     

Fracture behavior of recrystallized and stress-relieved Zircaloy-4 cladding under biaxial stress conditions

Pellet-cladding mechanical interaction (PCMI) under reactivity-initiated accident conditions may lead to failure of high-burnup fuel rods. The biaxial stress states of Zircaloy cladding tubes induced by PCMI loading presumably makes the tubes more susceptible to failure. To clarify the influence of the anisotropic mechanical properties of Zircaloy cladding tubes on their fracture behavior under biaxial stress conditions, biaxial tensile tests were performed, and the measured stresses and strains were converted to reduced parameters such as equivalent strain, equivalent stress, and stress triaxiality by using the anisotropic constants of the Hill yield function derived in our previous study. The minimum fracture strains of recrystallized (RX) and stress-relieved (SR) specimens were located where the stress ratio of axial to circumferential is 0.75. The equivalent plastic fracture strains tended to decrease monotonously with increasing stress triaxiality, which is a typical trend observed in ductile fracture, in the range of 0.65–0.78 for both specimens. In the case of SR specimens, however, the analysis with stress triaxiality did not reduce the fracture strains well to a single trend curve, showing that another influential factor is required such as an anisotropic fracture behavior or a plastic behavior deviated from that predicted by the yield function.     

A Study on High Subsonic Airfoil Flows in Relatively High Reynolds Number by Using OpenFOAM

In the present study, numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows. The airfoil model is NACA 64A010. The maximum thickness is 10 % of the chord length. The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows. The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively. The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past. The results are as follows. The nu- merical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel. And the data calcu- lated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low an- gle of attack.