Papers by Keyword: Flow Field

Abstract: Apply the CFD numerical simulation the internal flow field and noise when the control valve is bonnet leakage and trouble-free. Research shows that bonnet leaking has almost no effect on valve inlet and outlet flow field. It is an impact on valve body flow field and the greatest impact on balance cavity. It changes the flow direction of the balance cavity and produces right vortex, in balance cavity where originally without noise, the tremendous noise appeares and improves the noise of the surrounding area.

Abstract: Against the deflect that the existing fluidic gyroscope airflow channel structure was easy to cause the flocculating flow. This paper presented a kind of elliotic-drum flow cavity structure. Using the finite element method, calculated the flow field in the closed cavity at different angular velocity input. The results showed that the gas flow path of the main airflow distribution was streamlined, there did not form the vortex area which could reduce the energy additional losses, when the angular rate input changed, then the jet flow field distribution didnt keep equal and symmetrical, the jet speed difference at the hot sensitive wire changed with angular velocity, thus revealing the drum-shape cavity fluidic gyroscope sensitive mechanism.

Abstract: A device was designed to study the small holes by the rotary combined ultrasonic and electrochemical machining, and the gap between cathode and anode in the processing was also analyzed. A three-dimensional model of flow field was developed in ANSYS CFX software based on FEM by the gas-liquid two-phase fluid cavitations model as well as the effect of rotary cathode and the vibrated cathode to the flow field was analyzed. The simulation showed that the pressure and the velocity of the electrolyte in the gap were oscillated by additional motion of cathode, which is helpful to the electrochemical machining. The comparison of rotary electrochemical machining and the rotary combined ultrasonic and electrochemical machining showed that the rotary combined ultrasonic and electrochemical machining has better ability of making small holes than that of rotary electrochemical machining

Abstract: In the process of fans design, splitter blades could be adopted in the middle of rotator to improve the performance of fan. In order to understand the flow pattern in the high-pressure centrifugal blower of 9-26type with splitter blade thoroughly, computational fluid dynamics Fluent is applied and the three dimensional air flows in the fan is numerically simulated and analyzed. The calculating results showed that under the same condition, the flux of the fan was improved 5%approximately and the mean total pressure at outlet of the fan was improved 10% because of the splitter blade, the length of the splitter blade affected the flux either. Standard turbulent model and unstructured grids are applied in computation. The results of calculation can good helpful for people to improve the performance of the fan.

Abstract: Computational Fluid Dynamics (CFD) was used to simulate the flow field of gas-liquid Taylor flow in circular capillaries. The separate influence of gas bubble velocity V_b,Taylor unit length L_UC, film length L_film and liquid film thickness δ_film on both the liquid slug velocity V_x,top and film velocity V_x,film were investigated. The values of V_x,top are mainly dependent on V_b and δ_film while V_x,film relies on all the four parameters.

Abstract: The flow field produced by a plate propeller in a fully baffled flat bottomed cylindrical stirred tank with the diameter of 300 mm was measured using phase doppler particle analyzer. The radial distributions of the time-averaged, fluctuation velocity and turbulent kinetic energy were analyzed. The effects of off-bottom clearance and baffle on the flow field were investigated. The results showed that the fluctuation velocity and turbulent kinetic energy increased with increasing off-bottom clearance in the impeller region; meanwhile, the maximum values of the time-averaged and fluctuation velocity moved to the center of the stirred tank. The maximum axial velocity decreased with increasing off-bottom clearance in the bulk flow. The turbulent kinetic energy was higher in the impeller region. The maximum value of the turbulent kinetic energy increased with increasing off-bottom clearance and occurred near the end of the impeller. The baffle hindered the tangential velocity and exerted strong influence on the turbulent kinetic energy. The flow field in front of the baffle reflected the distribution of the turbulent kinetic energy in the impeller region.

Abstract: CAE technology is the most common method to study properties of impeller in a centrifugal compressor. The fluid field was numerically simulated by CFX program to obtain the distribution rules of pressure, turbulence intensity and erosion wear. Based on fluid-solid interaction, stress and deformation were analyzed by Ansys program. According to the simulation results, the maximum deformation and equivalent stress of the impeller are all located on the junction between the blade trailing edge and the shroud. The most serious damaged part by erosion wear in impeller is on the pressure surface of long blade. The erosion wear area on blade pressure surface caused by particles impact primarily locates on blade trailing edge root and middle part. In the flow field, the turbulent intensity on suction surface is greater than that on pressure surface in the corresponding position and the greatest turbulent intensity is located on the leading edge of suction surface. There is backflow phenomenon around the suction surface of long blade and the short blade has significant effect to reduce backflow. The results of numerical simulation explain some actual impeller failure cases and can be applied to anti-wear impeller design and repair.

Abstract: This paper presents the rudder inflow including fully non-uniform wake on a deep drafted LNG vessel in shallow water. The Ansys Fluent v.6.2 software was used to solve Reynold Average Navier-Stokes (RANS) equations, and Icem CFD as a mesh generator. The modeling was conducted based on the B 5-88 type propeller, with a diameter (D) of 7.7 meters. The propeller was meshed using tetra unstructured mesh in a flow field based on 3-Dimension incompressible Navier-stokes solver. It was found in the propeller-to-rudder interaction that there was a slight drop of pressure at rudder leading edge of 0⁰ rudder angle of attack (AoA). However, the dropped pressure was observed on its leading edge as the rudder angle of attack was increased to-7⁰. The effect of increasing rudder deflection was generated by the flow around it and inflows moved over the rudder. This deflection effect continued to X/D=0.4; afterwards, a zero velocity appeared because of the flow encountered by the stagnation region.

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: 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. Keywords:Tundish; Retaining Wall; Flow field; Mathematical Modeling; Inclusion;Optimization setting