Papers by Author: Yang Yang

Abstract: Aiming at some boiler tubescrack in a power plant, the element composition and the valence of elements in corrosion products on the outer surfaces of the boiler tubes were analysed by Scanning Electron Microanalyzer (SEM) and X-ray Photoelectron Spectroscopy (XPS), and the corrosion reason and mechanism of the outer surfaces of the boiler tubes were studied.The results showed as follows. (1)The content of element S in the corrosion products on the outer surfaces of the fire side boiler tubes was bigger than that in the corrosion products on the outer surfaces of the back side boiler tubes and the corrosion of the outer surfaces of the fire side boiler tubes was more serious than that of the outer surfaces of the back side boiler tubes. (2) the element S in the corrosion products existed in the form of sulfate (SO₄^2-), because the valence of S in the corrosion products on the outer surfaces of the fire side boiler tubes and the back side boiler tubes was +6, not-2. (3) the element Fe in the corrosion products on the outer surfaces of the fire side boiler tubes and the back side boiler tubes existed in the form of Fe₃O₄, Fe₂O₃ or Fe₂(SO₄)₃. (4) The corrosion of the boiler tubes was induced by sulphate under high temperature, and aggravated with the temperature of the outer surfaces of the boiler tubes elevated.

Abstract: The flow in a single-stage fan is analyzed through numerical simulation. The results indicate that there exists a best prewhirl angle which can make flow loss minimal at a given flow rate. So we can improve the internal flow field structure by changing the prewhirl angle, thus the fan efficiency can be raised. In addition, the flow separation on the suction surface is sensitive to the variation of the prewhirl angle. The range of the separation on suction surface increases with the decrease of the prewhirl angle, and expands to the central area of the blades.

Abstract: To increase the manufacture efficiency of electroplated diamond tools, a nickel plating solution containing ammonium sulphate and sodium formate was investigated. The effects of concentration of ammonium sulphate, sodium formate and pH value on throwing power, covering power, ability to resist Cu2+ contamination and deposit microhardness were studied. Surface topography of deposits was also observed by SEM. Compared to watts bath, the plating solution studied is advantageous in terms of the performance of plating solution, deposit hardness and diamond bit behavior. Ammonium sulphate can refine deposit crystal grains and result in crystal form change.