Advanced Materials Research Vol. 716

Abstract: Effects of hole shapes on film cooling effectiveness downstream of one row of film holes at the blade were investigated using a three-dimensional finite volume method and multi-block technique. The present study also received velocity vectors about different hole shapes. The hole geometries studied include standard cylindrical hole and forward diffused shaped hole and converging slot-hole. It was found that the film cooling effectiveness of cylindrical holes obviously declined along with increasing the blowing ratio. Results of the shaped holes configuration present a marked improvement, with a high effectiveness at the lateral area between adjacent holes and effectiveness of the converging slot-hole was superior to other holes in various blowing ratios. The film cooling effectiveness realized by the slot-holes compared to the cylindrical and forward diffused shaped holes was more excelled at downstream of the intersection of the two slot-holes. The converging slot-hole and forward diffused shaped hole can reduce the vortex intensity, and then enhance the film cooling effectiveness.

Abstract: The subway line will cross near the church St. Johann in the city. The foundation influence caused by tunnel construction from adjacent buildings will be simulated by software FLAC3D. And the feasible proposal of the construction will be resulted from the data which are collected from the field measurement and simulation. It plays an important role for coefficient of horizontal pressure K0 in simulating the geotechnical engineering. Comparing the data from the field measurement with simulation, the coefficient of horizontal pressure will be corrected. And the results of the simulation will be much closer to the real profiles.

Abstract: Biomass is a renewable energy. Its curing and molding technology is one of the key technologies and mould structure parameter is a important factor. A model is set based on ANSYS to simulate the molding, then the equivalent stress field and frictional force distribution of mould are founded. Finally, the relationship between maximum equivalent stress and mould parameter is studied.

Abstract: Two centrifugal pumps in reversal were selected as hydraulic turbines, one of which was equipped with a guide vane. Flow performance was simulated by Fluent. Radial forces of hydraulic turbine in different conditions were predicted. It was shown: when pumps in reversal were used as turbines, The radial forces were produced by the uneven dispersion of pressure in runner inlet. The radial forces increased with the increasing of discharge. Equipped with a guide vane, The inlet pressure in hydraulic turbine runner distributed more uniform than before, and the radial forces were reduced. No guide vane, the vector direction of radial force distributed between Volute Tongue and section VIII, while with a guide vane, the vector direction of radial force distributed between section IV and section VI. By adding guide vane for hydraulic turbine,the uniformity of pressure distribution in runner inlet can be improved and the radial force be decreased.

Abstract: The effect of bridge piles on separated island platform subway station performance was studied by performing two-dimensional numerical analysis. It turned out that the stress of subway station under piles tended to be larger than that without piles no matter under static analysis, dynamic analysis, or superposition of both analyses. Therefore, its necessary to consider the influence of piles on this kind of subway station in seismic analysis and, moreover, strengthen the stress concentrated areas.

Abstract: Based on the structure characteristics of electric spindle built-in motor and numerical heat transfer theory,electric spindle built-in motor physical heat conduction model was given and a mathematical temperature control model for the electric spindle built-in motor was established. According to the mathematical temperature control model, controllable factors for the heat balance was determined. By electric spindle own screw channels, using this mathematical temperature control model to adjust the flow speed and fluid medium temperature, the built-in motor quickly reached heat balance and maintained temperature field stability in the electric spindle start-stop and using process. Then the theoretical calculations and simulation on the electric spindle built-in motor was conducted.This model is designed to enhance high-speed precision spindle machining accuracy and the use of performance.Nomenclature:

Abstract: A new management method for storing and constructing phase diagram is proposed for purpose of reducing the amount of storage and improving the readability of the phase diagram. We name the new management method as Bezier curve modeled phase diagram (BCMPD) . An entire phase diagram is consists of a set of cubic Bezier curves and straight lines under the BCMPD. Bezier curve based data structure is used for existing phase diagram storage. is modeled by a cubic Bezier curve. The strategy of Bezier curve modeling each piece of curve within a phase diagram is discussed in detail. Experimental results proved the feasibility of the strategy. By using the proposed modeling strategy, users can construct a phase diagram more rapidly and precisely. Detail information within a phase diagram can be read easily by appointing a location in the drawing.

Abstract: The instability mechanism of propeller wake was investigated numerically on three propellers with different the numbers of blades. With the hybrid grid strategy and the sliding mesh, the Unsteady Navier-Stokes (N-S) and the Bubble Dynamics equations were solved to predict the axial velocity around the propellers and the vapor volume fraction in the blades surface. With the increasing of the numbers of propeller blades, the distance of the interaction decreases, and then the instability phenomena of the propellers wake are hastened.

Abstract: The riveting joint is the main connection to fasten two thin-walled sheet-metal parts in aircraft assembly. As one of important parameters in riveting process, the riveting force is mostly determined by the experience and experiments in actual production, lack of theoretical basis supported. This paper researched the maximum allowed value of riveting force in the elastic deformation stage of riveting process. Based on the theory of compression instability, the mathematics model of relationship among rivets diameter, rivet holes diameter and maximum riveting force was built. Then, by using the software for finite element analysis-ABAQUS, the instance of riveting process simulation was made. Finally, the result of instances simulation was compared with the mathematics model. The comparison shows that the mathematics model based on the theory of compression instability is effective and correct.

Abstract: Ultrasound elastography is a technique of imaging information about tissue elastic moduli, which plays an important role in early diagnosis of several kinds of tumor. Usually, elastograms display only axial displacement and corresponding tissue strain. In lateral direction, however, there is no phase information and the precision of data is lacking too. In this paper, a spline based method for lateral displacement and the corresponding strain estimation is proposed. SSE, which is computed based on lateral data lines in pre-and post-ultrasound signal, was used as a pattern-matching function to estimate lateral displacement. With this method, we can obtain directly continuous estimates with lower computational cost. The SNRe and CNRe of elastograms have been evaluated using simulated data.