Papers by Author: Shu Rong Yu

Abstract: The high cycle fatigue of super duplex stainless steel of SAF 2507 was investigated by rotating bending fatigue test in both air and 3.5% NaCl environment. The results showed that there is no much reduction of the fatigue life in corrosive environment, which is 90% of the air fatigue strength. In air fatigue, failure happens in ductile mode with austenite grains having finer and straighter fatigue striations than ferrite grains. Width and spacing of striations vary with the orientation and locations when the second cracking occurs. It is not reliable to identify the phase by morphology of striations. In 3.5% NaCl environment, the fracture exhibits a mixed mode of cleavage and quasi-cleavage in ferrites and ductile in austenite grains.

Abstract: Given mathematics model and boundary conditions of the structure optimization for ultra-supercritical bypass valve (UBV) in operation. FEM results showed that 10 design variables and 178 sampling points are chosen for iteration, and the relationship between maximum equivalent stress and structure parameters are obtained by sensitivity analysis. By using Monte-Carlo method, the quantity of optimized sampling point can be reduced by 17% and calculation time is reduced clearly. The higher sensitivity parameters affecting target function are found by contrasting response degree, and improving the parameters directly is the way that enhances intensity of the UBV. Base on the sensitivity analysis, the linearized equivalent stress of weak place in the UBV can be reduced by 44% with the safety performance enhanced.

Abstract: Given the heat transfer and force characteristics, seal ring was simplified to be equivalent to a circle. The heat transfer coefficients and temperature distribution on both rotating and stationary rings were calculated. A simplified thermal distribution model was developed for rotating and stationary rings according to the law of energy conservation and a verification method was proposed. Based on this, the deformation relationship of friction surfaces on which both heat and pressure were applied. Comparison was made between average and asymmetric thermal distributions and verified by FEM. The results showed that the deformation of stationary ring exceeds the allowed deformation amount in heat average distribution. The result of deformation is in agreement with testing results.

Abstract: a new method of locating the pinch is presented for the design of heat exchanger networks. The method is based on the pinch design method for heat exchanger networks which was first introduced by Linnhoff. The method first consider both the heat loss of a hot stream and the heat capacity flowrate of a stream with variation in temperature in the design of heat exchanger networks. Which affect not only minimum utility requirement for heat exchanger network but also the pinch location, choice ofΔTmin

Abstract: Free vibration of thermal post-buckled functionally graded material (FGM) beams in a uniform electric field subjected to both temperature rise and voltage is studied. Voltage has a great influence on the deformation of the beam, and Thermo-electric post-buckling equilibrium paths and characteristic curves of the first three natural frequencies versus the temperature, the electricity and the material gradient parameters are plotted. It is found that the three lowest frequencies of the pre-buckled beam decrease with an increase in the temperature, but those of a buckled beam increase monotonically with the temperature rise. The results also show that the tensional force produced in the piezoelectric layers by the voltage can efficiently increase the critical buckling temperature and the natural frequency.

Abstract: Fe₂O₃/attapulgite(ATP) catalyst was successfully prepared for Fenton reaction to degrade an anion surfactant, sodium dodecyl benzene sulfonate(SDBS)，in an aqueous solution. BET, SEM, FT-IR were performed to characterize Fe₂O₃/ ATP catalyst. Comparative studies indicated that the SDBS degradation ratios were much higher in presence of Fe₂O₃/ATP and H₂O₂ than those in presence of Fe₂O₃/ATP or H₂O₂ only, which suggested that the Fe₂O₃/ATP-catalyzed Fenton-like reaction governed the SDBS removal process. It also can be seen that Fe₂O₃/ATP-catalyzed Fenton-like reaction almost has the same efficiency as homogeneous Fenton reaction, while the former can be reused and has no secondary pollutants.

Abstract: Fe₂O₃/attapulgite(ATP) catalyst was successfully prepared for Fenton reaction to degrade anion an surfactant, Sodium dodecyl benzene sulfonate(SDBS). Through a number of batch degradation experiments under various conditions, it was found that the reactivity of the system increased by increasing Fe₂O₃/ATP dosage and temperature. The SDBS degradation ratio will increase with increasing H₂O₂ concentration at some extent. But too high H₂O₂ concentration will make degradation efficiency decrease. The system maintains high efficiencies all experimental pH value(2-10).

Abstract: Lattice Boltzmann methods (LBM) have become an alternative to conventional computational fluid dynamics (CFD) methods for various systems. In this paper, flow field of mean flow past a circular cylinder was simulated based on the lattice Boltzmann method. The streamline of air past the cylinder illuminated that the fluid adhere on the boundary and doesn’t separate from the surface of cylinder when Re number less than 5. When Re number equal 40, flow separated to form a pair of recirculating eddies can be observed. With the Re number increasing, the trailing vortex length is growth accordingly. When Re number come up to 80, the trailing vortex begin to shed regularly. This result is consistent with the experiment data. Drag coefficient that fluid act on the surface of cylinder was calculated. The calculated results were same as the experiment data. Simulation indicate that LBM can simulate the vortex taking place and shedding effectively.

Abstract: Sulfur dioxide is one of the major pollutants resulting from fuel combustion. In this study, CaO and attapulgite were utilized as raw material for synthesizing CaO/attapulgite(CaO/ATP) desulfurizer. The performance of samples was studied in dynamic conditions. Major factors affecting the desulfurization such as weight ratio of CaO to total, types of modifiers, desulfurizer particle size, bed temperature were investigated. The desulfurization agent synthesized under optimal synthesis conditions with an CaO content of 30 wt% and an NaOH modifier, and the desulfurization reaction processed under optimal synthesis conditions with water content of 20~30wt%, a particle size of 1/10 of desulfurization tower diameter and room temperature, exhibit sulfur tolerance of 17.97wt%.