The differences in material properties of different components of solid oxide fuel cells cause high stresses during sintering and operation, and functional gradient material electrodes are expected to alleviate this problem. In this study, electrodes with three different material compositions are compared with electrodes using conventional materials, and the residual and thermal stresses are calculated by applying functional gradient materials to single-sided and double-sided electrodes, respectively, and the results are analyzed with the optimization goal of minimizing the stresses to find the optimal functional gradient material composition distribution. The study shows that the functional gradient material electrode can significantly reduce the interfacial stress and alleviate the local stress concentration. When using functional gradient materials for one side of the electrode, a specific material component distribution can reduce the residual stress and thermal stress on the other side, but the stresses may increase on the local side of the electrode. The interfacial stress between layers can be reduced to a maximum of 0.1 MPa when a functional gradient material with a quadratic linear distribution of components is used for both sides of the electrodes. This study has implications for the fabrication of functional gradient materials for SOFC electrodes.

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In order to study temporal and spatial variation of energy loss and reveal influence rule of clocking effect on energy loss and flow field in centrifugal pump with vaned diffuser, numerical simulations were carried out. Numerical simulations were validated by experiments. Local equilibrium of turbulence generation and dissipation was verified to state feasibility of energy loss methods. Hydraulic loss in each component was assessed, which shows that variation of hydraulic loss in volute is more significant due to clocking effect than that in other components. Vortical structure in volute varies greater under different guide vane positions than it in other components. The results show that positive and negative flow angle appears interlaced in tongue region with high velocity gradient, especially when diffuser is mounted at θd1. Since a clearance presents between tongue and vane trailing edge at θd1, a small vortex forms. Which promotes the blocking effect of the large-scale vortex at volute outlet pipe. Therefore, high velocity gradient appears at small vortex region and volute outlet pipe region. The shear strain rate at the tongue and volute outlet pipe is more significant than that at other diffuser mounted positions. Energy loss at these regions increases. This situation can be improved by a more suitable diffuser mounted position θd4, where the clearance and small vortex vanishes, the shear strain rate, velocity gradient, and energy loss decrease.

In order to study the influence of solid particles in lead–bismuth alloy on the safety of nuclear main pump, DPM (Discrete Phase Model) is used to calculate the wear rate of the impeller of nuclear main pump under different operating conditions. By comparing the erosion rate and the most severe erosion area under different working conditions, the most unfavorable operating conditions are obtained. The results show that the erosion of impeller caused by solid particles is the most serious when the inlet velocity of particles [Formula: see text] is 0.4[Formula: see text]m/s and particle size [Formula: see text] is 100[Formula: see text][Formula: see text]m. Under the small particle size, the impeller erosion concentrated on the suction side of the blade, and under the large particle diameter, the erosion concentrated on the pressure side, and the erosion is more serious. With the increase of solid particle velocity, the erosion of the impeller increases first and then decreases. The erosion severity of impeller and front and rear cover plates caused by solid particles is not consistent. The above research can provide guidance for the anti-wear design and safe operation of the nuclear main pump impeller.