Advanced Materials Research Vols. 774-776

Abstract: Through toppling Bernoulli equation, gain the application of Bernoulli equation in fluid mechanics. Pay close attention to solve the problem concerning how to use it to calculate the engineering data,and how to explain some common phenomenon in our daily life .

Abstract: In a closed pulverized coal preparation system, a special device must be installed to vent flames and pressure during unexpected dust explosions. A vent flame arrestor is a key element in this device, which helps prevent a dangerous second explosion by venting flames. Traditional vent flame arrestors are designed with mounting metal fiber or rock fiber on both the sides and the top of the arrestor to cool dust flames and arrest burning dust during an explosion. This type of arrestor is widely used, but their application is still problematic, even for St1 dust at low reduced pressure (Pred). To solve these problems, we designed two types of flameless venting devices. The first is intended for St1 dust explosion venting at Pred 0.07 MPa, and was modified from an original device by adopting a labyrinth-like structure in the interior space to successively reduce the strength of the dust flame. The second is intended for St1 dust explosion venting at 0.07 < Pred 0.18 MPa, and was modified from the first type by adding a special suppressant in the interior space to make the dust flames cooler than the ignition point of the dust. Our experiments confirmed that our designs yield improved efficiency of flameless venting devices, leading to safer vent flame arrestors.

Abstract: In order to investigate 3-D situation, the wind and the waves on the interaction on the influence of water object characteristics, this article through to the second development software Fluent, numerical simulation for 3D wave the dynamic process of the wave. First of all a three dimensional two phase numerical pool, the definition made wave plate boundary for movement, according to the characteristics of sine wave launch made wave plate movement rules, and through the user-defined function (UDF) DEFINE_CG_MOTION macro, realize the made the movement of wave plate, analyzes the cycle 2 s stroke 3 m and cycle 6.0 s stroke 0.5 m of sine wave. Second, blowing and horizontal plane Angle 45 ° 2.0 m/s wind, get the jump irregular wave wave process. The results found that reduce the maximum wind trough value, at the same time, improve the big wave peak, adding to the pool of wave, for numerical simulation of 3-d situation seas over deck, leak, prevent oil spill and the foundation animals.

Abstract: In order to study the influence of oil tank with different throat areas on mirror-plate-pump performance, numerical simulation by applying ANSYS CFX software was conducted between four oil tanks with different throat areas, which combined with the same mirror plate respectively. Contrastive analysis of external characteristics of different runner-pumps and energy losses in different oil tanks show that the change of throat area has little effect on the brake horsepower curve, but it has great influence on head and efficiency curve, both of which first move up and then decline with the decrease of throat area in the whole calculation flow range, and at the same time the change of throat area causes great change of losses in oil tank. Achieving the best match relationship between oil tank and mirror plate in design process can make mirror-plate-pump display the best performance.

Abstract: To analyze the radial oscillation of forced acoustic gas bubble in liquid, a revised model including the effect of compressibility is mathematically formulated. Based on proposed model, the effects of fluid viscosity and temperature are discussed respectively. Numerical study demonstrates that gas bubble oscillation may change from nonlinear chaos into linear one due to the augmentation of fluid viscosity. Meanwhile, the stable oscillation may diverge with a sensible rise in temperature.

Abstract: The FSC racing pneumatic transmission system of South China University of Technology realize shift semi-automatic, drivers can be more convenient and completed shift operation in a shorter period of time,so as to improve the results of the competition. According to the preset program driving shift cylinderand clutch cylinder ,compressed carbon dioxide under the manipulation of electronic control unit complete whole transmission process. This paper detailed discusses actuator and electronic control unit design process, at the same time on debugging problems arising from the car, put forward the optimization direction of the system.

Abstract: The hydraulic system of screw distributor plays an important role in asphalt paver. It belongs to the speed-regulating system of pump controlled motor. The motor speed and direction of rotation can be controlled by variable delivery pump. Thus the transferring speed of bituminous mixture can be adjusted. The mathematical model of the system is presented, and dynamical characteristics are analyzed. Simulation results indicate that the system is suitable to screw distributor and has high operating efficiency. By changing the angle of swashplate, the rotating speed of motor can be adjusted proportionally. The undamped natural frequency of the system is lower for two reasons. One reason is only one line controlled by the trapped oil spring rate. The other reason is larger volume of pump.

Abstract: Used turbine blades are replaced by new once based on manufacturers recommended useful life. However, depending on the turbine operating conditions the blades might have different creep service life. Thus, the aim of this study was to predict the remaining creep life and investigating the microstructure of used gas turbine blades. This was done by using Larson-Miller parameter and Robinson life fraction rules under certain conditions of stress and temperature. The change in microstructure of the materials was analyzed by using the Field Emission Scanning Electron Microscope (FESEM). The result shows that turbine blades suffered from several microstructure changes based on their service life. The method used to predict the remaining useful life of used turbines could be an input to a decision to repair or replace used turbine blades. Keywords: Larson-Miller parameter,life fraction rule, microstructure, creep life, turbine blades.

Abstract: Placement in the middle retaining wall package, aimed at controlling the flow of liquid steel forms, so that movement of a reasonable level remained stable, while reducing interference from turbulence and dead zones, molten steel in order to extend the average stay of removal in favor of inclusion to improve the cleanliness of molten steel.In this paper, with the tundish wall flow field of research is the use of mathematical simulation methods, three dimensional mathematical models are currently being used successfully to simulate liquid steel flow and temperature distribution, the large-scale universal Finite Element analyses software ANSYS CFX is used and many models based on different tundishes are built

Abstract: A finite volume method for the numerical solution of viscoelastic flows is given. The flow of a differential Phan-Thien-Tanner (PTT) fluid through an abrupt expansion-contraction channel has been chosen as a prototype example. Through the results of numerical simulations, the contours of velocity and stream function are drawn. Numerical results show that the viscoelasticity of polymer solutions is the main factor influencing the sweep efficiency. With increasing elasticity, the flowing area in the channel is enlarged significantly, thus the area with immobile zones becomes smaller, the microcosmic sweep efficiency increases. The visco-elastic nature of the displacing polymer fluids can ingeneral improve the displacement efficiency in pores compared to using Newtonian fluids. This conclusion should be useful in selecting polymer fluids and designing polymer flooding operations.