Applied Mechanics and Materials Vols. 635-637

Abstract: Subway is an efficient transportation to alleviate the intensive traffic in modern cities. In the case of fire, it will bring out serious casualties and property losses. This research analysis the accident causes and characteristics in subway fire and flue gas flow analysis of mechanical smoke control track area of fire. The results and conclusions of this research are of great significance and practical value for the subway fire prevention and fighting，and have great reference value to the performance-based fire design in subway fire．

Abstract: In this study, the commercial code was used in order to derive the discharge flow rate and the thrust force in accordance with the rotational speed of the 3-dimensional blade of screw propeller. In addition, computational domain was considered in this research and it was realized by the analysis in the blades and the outlet chamber. Furthermore, a total of 2,640,222 mesh was calculated in consideration of unstructured mesh and the analysis was performed according to the total of the rotating speed (3200, 2400, 1600, 800rpm). The analysis was carried out on the pressure distribution, discharge flow rate and consequent thrust force according to the rotational speed. Especially, the analysis was realized focusing on the condition of 3200rpm. The difference between the maximum pressure and the minimum was 5.5MPa in the given condition and the discharge flow rate as to the pressure difference was the level of 1956.67 kg/s, as the thrust force of 47083.7 F(N) was obtained. In addition, it was considered that occurrence of cavitation in the given condition is closely related the decrease of durability of screw propeller in the aspects that the thrust force on driving depends on the speed.

Abstract: Medium pressure water asphalt heating equipment and hot oil asphalt heating equipment widely used in asphalt concrete mixture are using indirect heating method. In indirect asphalt heating device design, heating coil full of heating medium in asphalt tank and asphalt delivery pipe to next technological tank or asphalt concrete mixing device are key parts for the heating technology. Based on heat-transfer mechanism of heating medium, medium pressure water and hot oil have been compared, and medium pressure water has been chosen as heating medium for better character in heat transmission capability and efficiency. By thermo technical calculation, diameter,length and layout of heating coil have been decided, and structure of asphalt delivery pipe has been designed. Equipment running effect shows pipeline of medium pressure water system is designed reasonably and goal temperature of asphalt can be reached.

Abstract: A heat sink is a kind of heat exchanger that cools a device by dissipating heat into the environment. The design of heat sink by numerical simulation depends to a large extent upon boundary condition between the heat sink and its surroundings. The boundary condition is usually defined by Heat Transfer Coefficient (HTC) which can be used to measure heat resistance between heat sink and surrounding. Determination of HTC is a difficult problem, depending on many factors such as air velocity, material properties, shape of radiators and surface treatment, etc. A new simple reverse method has been suggested in the present work. The reverse method is suggested according to Mean-Value Theorem in mathematics. By comparing the temperature curves between simulation and real measurement, the temperature differences can be minimized by selecting different HTCs.

Abstract: Now in Russia construction of buildings with framework use from a metalwork which show itself as universal, strong, easy and fast-built is actively conducted. There are offers and initial experience of application of easy steel protecting designs with an effective heater in multystoried frame residential buildings, but without sufficient theoretical and experimental justification.In this regard, the question of determination of the heatphysical properties, in particular the specified resistance to a heat transfer, is actual.Results of laboratory researches of the specified resistance are presented to a heat transfer of an easy protecting design in article.

Abstract: The roots compressor is a kind of rotary compressors, it is applied widely in mechanical engineering, chemical industry, aerospace industry and other fields with its high speed, long life and mechanical efficiency. In the article, a new combination rotor profile curve of the roots compressor was designed by reviewing the relevant literatures, the 2D finite element modal was established and a transient CFD numerical simulation was performed for a roots compressor by means of dynamic mesh technique. The varying tendency of mass flow rate, the velocity vector and static pressure distribution of the roots compressor were obtained and analyzed.

Abstract: In this paper, the influence of the soft magnetic particle content on the properties of MRFs is studied. Besides, the relationships between the shear stress of MRFs and the magnetic induction intensity, the soft magnetic particle content, and the shear rate are discussed. The curve equation that expresses the relationship between the shear stress, the magnetic induction intensity, and the soft magnetic particle content is established through the fitting of experimental data. The results show that the shear stress of MRFs increases with increasing magnetic induction intensity and that the shear stress will tend to stabilise when the magnetic induction intensity reaches a sufficient value. The validity of the Bingham model and the H-B model for describing the relationship between the shear stress and shear rate is established, and the phenomenon of shear thinning of MRFs can be better represented by the H-B model than by the Bingham model.

Abstract: Examined efficiency of axial rotor wheels microturbines. The mathematical models, regression-type, for efficiency rotor wheels and the exit angle of the working body from rotor wheels are presented. The technique of determining the gas-dynamic and structural characteristics of the flow part of the rotor wheels microturbines are also shown.

Abstract: The flame used in combustion flame spraying is typical of a high-temperature free jet. The flow fields of free jets are multi-phase flows that couple the mass and heat transfer. This work develops an analytical method to describe free combustion spray jets. The aim of the research is to develop a fully understanding of the characteristics of free-flame jets. Experimental measurements were carried by a unique high-speed continuous CCD camera.

Abstract: In this paper, we propose a method of calculation and optimization concerning the dynamic parameters including its normal stiffness and tangential stiffness. We establish a contact model and a dynamic model based on Hertz contact theory, deriving and calculating its normal stiffness and tangential stiffness. Based on the dynamic parameters obtained, we complete the finite element analysis (FEM) and make the modal experiment. verify the correctness and feasibility of the theory model and the FEM model through comparing the theoretical results with the experimental results. On this basis, we establish the dynamic parameters optimization model based on the ANSYS and MATLAB, and successfully obtain more accurate parameters which provide reliable data for the subsequent analysis.