Papers by Keyword: Velocity Distribution

Abstract: To study the velocity and pressure distribution of the oil film in a heavy hydrostatic thrust bearing, a mathematical model of the velocity is proposed and the finite volume method (FVM) has been used to simulate the flow field under different working conditions. Some pressure experiments were carried out and the results verified the correctness of the simulation. It is concluded that the pressure distribution varies small under different rotation speed when the surface load on the workbench is constant. But the velocity of the oil film is influenced greatly by the rotation speed. When the rotation speed of the workbench is as quick as enough, the velocity of the oil film on one radial side of the pad will be zero, that is to say the lubrication oil will be drained from the other three sides of the recess.

Abstract: This measuring system is designed to improve the accuracy of the pipe-flow measurement based on the Doppler method. It uses plane concave sound lens to converge the ultrasonic sending and receiving beam, reduce the volume of the Doppler information window and realize the measurement of fluid flow in pipe with the Doppler method. With the application of DSP digital signal processing technology to design this flow measuring system, it achieves accurate measurement of fluid flow in pipe. Experimentation proves that the measuring accuracy of the system is higher than 1%.It is of great significance to realize high precision of pipe-flow measurement based on the Doppler method.

Abstract: The velocity and sludge distribution in the aerobic tank of step-feed A/O process were simulated by the two-phase flow model. The aeration process was simulated by the discrete phase model and the influence of the aeration on the sludge distribution was studied. The space distribution of the wastewater-sludge-bubble in the aerobic tank was determined. The results showed that the sludge age is hard to be control led as the eddies in the aerobic tank have a strong influence on the sludge retention time. The impact of the aeration on the mean sludge concentration is neglectable. The uniformity of sludge distribution along the vertical direction and the sludge sedimentation on the bottom layer are improved by the process of aeration. The results have great theoretical significance and guidance for the optimal design of the aerobic tank of step-feed A/O process.

Abstract: The feasibility of the rigid-lip hypothesis was studied in the flow field simulation of the reaction tank in the step-feed A/O process. Two models were built. One model applied the rigid-lip hypothesis was called as rigid-lid model and the other was called free surface model. The results showed that the velocity distribution of the rigid-lid model is basically consistent with that of the free-surface model. On the vertical monitor sections, the error of the mean velocity between the two models is less than 8%. The results showed that the much less expensive rigid-lid model is applicable to simulate the flow field of reaction tank.

Abstract: Fishway is an effective engineering measure to keep the river longitudinal connectivity and maintain aquatic biodiversity. In this experiment, the pool-type fishway with asymmetric notches and orifices was studied, the ADV was employed to measure the velocity data in the pools, the flow velocity and flow regimes in the pools with the length of 0.5m, 0.6m and 0.7m at different measuring lines were analyzed. The results show that the maximum velocity is 0.35±0.025m/s in the three kinds of pools, and both the backflow region and the backflow velocities are correspondingly increased with the increasing length of the pool.

Abstract: Darcy's law is found be not applicable to fluid flow in small pore throat, and the mechanism for the nonlinear flow is still unclear to date. The paper analyzed the influence of various types of micro forces in porous media on fluid flow, based on the existing experimental results and theoretical knowledge of micro-scale flow. Mathematical model for flow in small tube was established with the consideration of Van der Waals force between solid and liquid. By simulating velocity distribution and the average flow under the Poiseuille flow, we get that with the decrease of the micro tube size, the Van der Waals force between solid and liquid increases and the effect on flow pattern of fluid in the tube increases, so that the Van der Waals force between solid and liquid in the tiny pore flow should not be ignored.

Abstract: Direct reduced iron (DRI) shaft furnace flow field has important influence to the DRI production process, and the ventilation is a key factor for the velocity and pressure distribution of the gas flow in the furnace. At present works, the direct reducing gas velocity distribution and pressure distribution of DRI shaft furnace were studied with different ventilation. By the analysis of numerical simulation, the result was found that the direct reducing gas velocity increase with height in the shaft furnace reduction section. The velocity of the direct reducing gas augment with the increase of ventilation. The direct reducing gas pressure add with increasing height in the shaft furnace reduction section. With ventilation increasing, the pressure of the shaft furnace ventral part increase, and the pressure gradient increase in the direction of height in the DRI shaft furnace.

Abstract: The flow characteristics of fish-bone type dividing dike is very complicated. By model experiment, this paper deeply research in water surface line, velocity distribution and the flow regime of fish-bone type dividing dike. It can Provided the certain basis for the design of fish-bone type dividing dike, such as a fishbone in dam engineering stab dam ridge direction, length, and layout spacing, length.

Abstract: Using Moldflow software, numerical studies of the Three-dimensional velocity vector distribution of molten fluid in the process of filling the inside mold cavity in one-step[1] injection mold filling method, analysis of the melt flow front temperature in mold cavity, cavity pressure and die time under the conditions of different injection pressure. The results of the simulation have some theoretical significance on the designing mold and choice of injection process.

Abstract: In order to solve the problems of flow measurement and to obtain the sectional velocity distribution of open channel, the FLUENT simulation method was adopted. The velocity-area method based on the sectional velocity distribution was introduced, and the flow measurement equipment of open channel was also designed. The experiment result shows that the error of the method is less than 1%.