Papers by Keyword: Pressure Distribution

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: Cooling roll is a key component in preparation of amorphous alloy ribbon process. The cooling roll rotates at a high speed that causes large centrifugal force on coolant. The reasonable channel structure facilitates the cooling effect and decreases power consumption. Different channel structures in the cooling roll are analyzed in this paper by computer fluid dynamic (CFD) method. The simulation calculated out the pressure distribution and streamline in different channel structure. The simulation results show that flow in case 2 is the optimal in three channel structures. Finally, the structure of the case 2 is manufactured and tested. It is shown that there is no flow block in the channel.

Abstract: The vent or opening is called nozzle. The objectives are to measure the flow rates and pressure distributions within the converging and diverging nozzle under different exit and inlet pressure ratios. Analytic results will be used to contrast the measurements for the pressure and normal shock locations. In this paper computational Fluid Dynamics (CFD) Analysis of various performance parameters like static pressure, the Mach number, intensity of turbulence, the area ratio are studied in detail for a rocket nozzle from Inlet to exit by using Ansys Fluent software. From the public literature survey the geometry co-ordinates are taken. The throat diameter and exit and diameter are same for all nozzles. After the simulation the results revealed that the divergence angle varies the mach number and other performance parameters also varies. For smaller nozzle angle the discharge coefficient increases with increasing pressure ratio until the choked condition is reached for varying the divergence angle.

Abstract: Models with main-branch channel, crossing channel and net type channel are established and nutrient liquid with a velocity of 0.01m/s is adopted in the study to investigate the fluid field in the channel by using FEA software FLUENT. The velocity and pressure distribution have been obtained in the investigation. By comparing the results in the three models, pressure and velocity distribution in the second and the third models are relatively uniform and are appropriate for the bionics principles. Studies in this paper will be of benefits for the development of tissue engineering.

Abstract: The finite element method was used to analyze the bubble in the ship wake. The single bubble model in the ship wake was created and studied after the material property parameters of the bubble were got by the finite element computation. The finite element model was then analyzed by SYSNOISE. From the analyzing, the displacement of the point on the surface of the bubble was gained when the sound press changing as the frequency varies; the distribution of the pressure was displayed when the frequency of the sound is equal to the resonant frequency of the bubble.

Abstract: This study aims to analyze the functional contact pressure induced by Removable Partial Denture (RPD) by using a 3D finite element (FE) model constructed based on patient specific CT scans. This model was validated against the in vivo test results. The outcomes demonstrate that the finite element simulation has the capability of quantifying localized stress distribution in a complicated denture-mucosa contact problem, with a reasonable matching to clinical measurements of occlusal force and pressure distribution. The methodology is of considerable clinical implication to improve the long term outcomes of the denture treatment.

Abstract: The accuracy prediction of the strip's upper pressure and lower pressure is very important to the accuracy control of air flotation oven, therefore the aluminum can get high surface quality and improving the product quality. And the pressure prediction is very important factor in air flotation oven. In this paper, pso-lssvm pressure prediction model was established. The experiment was carried out in an experimental air flotation oven and pressure data was collected, then the pso-lssvm model was trained based on the training data. The pso-lssvm pressure model' result was compared with the experimental value. The experimental result shows that the pso-lssvm model can get higher accuracy and is suited to predict pressure 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: Flow characteristics of two different diameters cylinders in a tandem arrangement were investigated numerically in a uniform flow. The diameter of the downstream main cylinder was kept constant, and the diameter ratio between the upstream control cylinder and the downstream one was varied from 0.1 to 1.0. The studied Reynolds number based on the diameter of the downstream main cylinder were 100 and 150. The gap between the control cylinder and the main cylinder ranged from 0.1 to 4.0 times the diameter of the main cylinder. It is concluded that the gap ratio and the diameter ratio between the two cylinders have important effects on the lift coefficients and pressure distribution.

Abstract: Pressure distribution of supercritical airfoil at flight Reynolds number could not be fully simulated except in cryogenic wind tunnel such as NTF (National Transonic Facility) and ETW (European Transonic Wind tunnel), which is costly and time resuming. This paper aimed to explore an engineering extrapolation to flight Reynolds number from low Reynolds number wind tunnel data for supercritical airfoil pressure distribution. However, the extrapolation method requiring plenty of data was investigated based on the CFD results for the reason of low cost and short period. Flows over a typical supercritical airfoil were numerically simulated by solving the two dimensional Navier-Stokes equations, with applications of ROE scheme spatial discretization and LU-SGS time march. Influence of computational grids convergence and turbulent models were investigated during the process of simulation. The supercritical airfoil pressure distribution were obtained with Reynolds numbers varied from 3.0×10⁶ to 30×10⁶ per airfoil chord, angles of attack from 0 degree to 6 degree and Mach numbers from 0.74 to 0.8. Simulated results indicated that weak shock existed on the upper surface of supercritical airfoil at cruise condition, that the shock location, shock strength and trailing edge pressure were dependent of Reynolds number, attack angles and Mach numbers. A similar parameter describing the Reynolds number effects factors was obtained by analyzing the relationship of shock wave location, shock front pressure and trailing edge pressure. Based on the similar parameter, airfoil pressure distribution at Reynolds number 30×10⁶ was obtained by extrapolation. It was shown that extrapolated result compared well with simulated result at Reynolds number 30×10⁶, implying that the engineering method was at least promising applying to the extrapolation of low Reynolds number wind tunnel data.