The Flow Phenomena and the Non-Uniform Filling of the Unvulcanized Rubber in Process of Filling

2009 ◽  
Author(s):  
Shintarou Sakai ◽  
Toru Shigemitsu ◽  
Junichiro Fukutomi ◽  
Tsukasa Matsuoka
Keyword(s):  
Numerical Analysis ◽  
Narrow Channel ◽  
Numerical Results ◽  
Flow Conditions ◽  
Flow Phenomena ◽  
Rubber Product ◽  
Vulcanization Process ◽  
Filling State ◽  
Optimum Flow ◽  
Good Agreement

Rubber products like oil seal are produced by vulcanization molding and the vulcanization molding of rubber product is performed by past experience, trial and error. It is important issues to decrease the product cost, reduce defective products and solve the environmental problems by saving natural resources. If the vulcanization moldings of rubber products are reappeared by computer simulation, it is very useful and it could contribute to solve the above problems. In order to reduce surplus rubber and defective products, numerical analysis of flow phenomena of unvulcanized rubber was performed using commercial software FIDAP. In several types of rubber mold model, the numerical analysis was conducted taken the characteristic of visco-elasticity fluid obtained by an experiment without considering the effect of heat. And experiments were conducted for the comparison of numerical results and actual phenomena. In the experiment, vulcanization process was stopped by arbitrary interval. Then the filling state and the shape of the rubber at each interval are observed in numerical and experiment results. The results showed that the filling state of numerical results represented good agreement with the experimental results. And it was clarified from the numerical analysis that shear stress increased when the unvulcanized rubber flowed in a narrow channel and there was the relation between pressure and velocity. In the present paper, the flow phenomena under the condition of the compression molding are shown and the optimum flow conditions are discussed from the numerical results. Furthermore mechanism of occurrence of defective products is considered with the experimental and the numerical results.

Study on the Air-Side Heat Transfer and Pressure Drop for Fin-Tube Heat Exchangers

2002 ◽  
Author(s):  
Ji Hwan Jeong ◽  
Keun Sun Chang ◽  
Young Chel Kweon ◽  
Sang Jae Lee ◽  
Min Kyu Lee
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Unit Area ◽  
Numerical Results ◽  
Experimental Measurements ◽  
Air Velocity ◽  
Fin Tube ◽  
Good Agreement

Experimental measurements and numerical analysis have been carried out in order to investigate performances of air-side heat transfer and pressure drop for six types of heat exhcangers with various fin shapes. An air-enthalpy calorimeter is used in this work. Numerical analysis shows a good agreement with experimental measurements. Measurements for six types of heat exchangers at various air-velocity are compared with each other. Heat transfer per unit area appears to be nearly the same in the range of 0.7~0.9 m/s while it varies within 3% at 1.5 m/s. The numerical results show that most of heat transfer takes place through fins for all types and majority of heat transfer happens from the 1st row.

Internal Flow Condition of Fluid Food Pump Using Semi-Open Impeller

2015 ◽  
Author(s):  
Toru Shigemitsu ◽  
Hirotaka Shinohara ◽  
Takumi Matsubara ◽  
Junichiro Fukutomi
Keyword(s):  
Numerical Analysis ◽  
Flow Condition ◽  
Design Method ◽  
Internal Flow ◽  
Axial Position ◽  
Flow Conditions ◽  
Flow Passage ◽  
Flow Phenomena ◽  
Turbo Pump

Fluid machineries for fluid food have been used in wide variety of field i.e. transportation, filling, and improvement of quality of fluid food. Although, flow conditions of these are quite complicated because fluid food is different from water. Therefore, a design method based on the internal flow conditions is not conducted. In this research, turbo-pump having small number of blade was used to decrease shear loss and keep wide flow passage. The flow phenomena were not clarified in detail, although, it was found that internal flow condition was complex in the test pump in previous studies. In order to investigate the complex internal flow condition, the unsteady numerical analysis using low viscous fluid was conducted. In this paper, the internal flow conditions at each axial position of the centrifugal pump having semi-open impeller were investigated by the numerical analysis results. In addition to that, the influence of the internal flow conditions on its head was clarified.

scholarly journals Estimation of Initial Debonding Stress in Adhesive Structure between Concrete and Composites

1996 ◽  
Vol 5 (3) ◽  
pp. 096369359600500
Author(s):  
Atsushi Yokoyama ◽  
Akihiro Fujita ◽  
Shigeo Urai ◽  
Hiroyuki Hamada
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Finite Element ◽  
Composite Material ◽  
Composite Materials ◽  
Numerical Analysis ◽  
Bonding Strength ◽  
Concrete Structures ◽  
Numerical Results ◽  
Good Agreement

This paper describe a numerical analysis using finite element method(FEM) to investigate effects of composite material on repairing of concrete structures. The numerical results were in good agreement with the experimental data. Particularly, bonding strength between composite materials and concrete was investigated.

Flow Phenomena in a Highly-Loaded Single-Stage Axial-Flow Pump: Comparison of Experimental and Numerical Results

2007 ◽  
Author(s):  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen ◽  
Marina Schmidt
Keyword(s):  
Flow Structure ◽  
Flow Behavior ◽  
Axial Flow ◽  
Numerical Results ◽  
Operating Conditions ◽  
Flow Conditions ◽  
Part Load ◽  
Flow Phenomena ◽  
Operating Points ◽  
Highly Loaded

In highly loaded axial flow pumps considerable changes of the flow behavior were reported when altering the flow rate from design point operation to part load operation. The flow structure which is changing from stable operating conditions to stalled flow conditions has been investigated in detail by Kosyna and Stark with experimental methods. The present paper focuses on the application of numerical methods to simulate the flow behavior in the pump which has been investigated experimental. The obtained numerical results using a commercial solver for the unsteady Reynolds averaged Navier-Stokes equations (URANS) have been compared to the experimental results of Kosyna and Stark et al. The characteristic of the pump at different operating points is compared to the measurement. The change in the flow structure at part load conditions which gives a decrease of head is reproduced by the simulation results. The vortex structure induced by the tip leakage flow is a flow phenomenon which is well-known in external aerodynamics and in axial-flow compressors at flow conditions close to stall. The change of this vortex structure at different operating conditions is shown. Also the part load recirculation vortex dominating the rotor tip flow at deep stall conditions as well as the cross passage vortex is visualized from the numerical results. All addressed flow phenomena are shown in contrast to the findings of the experimental investigations. This comparison of the flow fields for appropriate operating points shows that the reported change in the flow structure can be detected by numerical simulation as well.

Two-Phase Model for Simulating Current-Induced Scour Beneath Subsea Pipelines at Different Initial Elevations

2018 ◽  
Author(s):  
Jun Y. Lee ◽  
Jasmin B. T. McInerney ◽  
Fauzi A. Hardjanto ◽  
Shuhong Chai ◽  
Remo Cossu ◽  
...  
Keyword(s):  
Numerical Results ◽  
Scour Depth ◽  
Flow Conditions ◽  
Eulerian Model ◽  
Two Phase ◽  
Mesh Dependency ◽  
Steady Current ◽  
Equilibrium Scour Depth ◽  
Subsea Pipelines ◽  
Good Agreement

When a subsea pipeline is laid on an uneven seabed, the pipeline can have an initial elevation, potentially compromising its on-bottom stability; scouring due to flow conditions around the pipe can further exacerbate the problem. We assess the capability of the two-phase Eulerian-Eulerian OpenFOAM solver, twoPhaseEulerFoam, in terms of predicting the equilibrium scour depth beneath a pipe at different initial elevations under a steady current for the live bed condition. The predictions were found to be in good agreement with published experimental and numerical results; however, similar to a recent study involving another two-phase Eulerian-Eulerian model, the scour time scale was under-predicted. The predicted equilibrium scour depth was seen to decrease with an increase in the initial pipe elevation. The numerical results were also compared to predictions that were made using previous empirical equations. The most comprehensive equation to date showed a good agreement with the present numerical results. We conclude that this open-source solver, twoPhaseEulerFoam, can be used to predict the equilibrium scour depth beneath subsea pipelines, with short computation times and negligible mesh dependency.

scholarly journals Effect of Blade Profile on the Performance of Wells Turbine under Unidirectional Sinusoidal and Real Sea Flow Conditions

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
A. Thakker ◽  
R. Abdulhadi
Keyword(s):  
Unsteady Flow ◽  
Numerical Results ◽  
Blade Profile ◽  
Flow Conditions ◽  
Wells Turbine ◽  
Hysteretic Characteristics ◽  
The One ◽  
Good Agreement

This paper presents the effect of blade profile and rotor solidity on the performance of Wells turbine operating under unidirectional unsteady flow conditions. In the study, four kinds of blade profile were selected, that is, NACA0020, NACA0015, CA9, and HSIM 15-262123-1576. The experiments have been carried out for two solidities,σ= 0.48 andσ= 0.64, under sinusoidal and irregular unsteady flow conditions based on Irish waves (site2). As a result, it was found that the preferable rotor geometry is the one with blade profile of CA9 with solidityσ= 0.64. In addition, the effect of blade profile and rotor solidity on hysteretic characteristics of the turbine has been clarified experimentally and it was found to be in good agreement qualitatively when compared to numerical results (Setoguchi et al. (2003)).

Experimental and Numerical Investigation on the Influence of Trailing Edge Bleeding on the Aerodynamics of a NGV Cascade

2009 ◽  
Author(s):  
Marco Montis ◽  
Reinhard Niehuis ◽  
Mattia Guidi ◽  
Simone Salvadori ◽  
Francesco Martelli ◽  
...  
Keyword(s):  
Guide Vane ◽  
Measured Data ◽  
Flow Conditions ◽  
Trailing Edge ◽  
Pressure Losses ◽  
Ejection Rate ◽  
Nozzle Guide Vane ◽  
Flow Phenomena ◽  
Nozzle Guide ◽  
Good Agreement

A series of tests on a specific designed linear nozzle guide vane (NGV) cascade with trailing edge coolant ejection was carried out to investigate the influence of the trailing edge bleeding (TEB) on the loss behaviour of the profile. Wake traverses with a five-hole probe and measurements of the pressure distribution on the profile were taken varying the ejection rate under reference main flow conditions, namely Re2th = 1.056·106 and Ma2th = 0.8 (Re2th based on the true chord). Wake total pressure losses and isentropic Mach number distributions on the profile were compared to measurements without coolant ejection, showing a significant influence of the TEB both on the wake development and on the flow in the vane passage. Numerical simulations of the experiments showed good agreement with the measured data and provided a deeper understanding of the flow phenomena, revealing the differences in the development of the wake with and without trailing edge coolant ejection and illustrating the blockage effect of the TEB on the flow in the vane passage.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

Modeling of mass transfer in biofilms in oscillatory flow conditions using k-ɛ turbulence model

2003 ◽  
Vol 3 (1-2) ◽  
pp. 201-207
Author(s):  
H. Nagaoka ◽  
T. Nakano ◽  
D. Akimoto
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Turbulence Model ◽  
Uptake Rate ◽  
Oscillatory Flow ◽  
Substrate Uptake ◽  
Flow Conditions ◽  
Mass Transfer Mechanism ◽  
Substrate Uptake Rate ◽  
Good Agreement

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions. Numerical simulation of turbulence near a biofilm was conducted using the low Reynold’s number k-ɛ turbulence model. Substrate transfer in biofilms under oscillatory flow conditions was assumed to be carried out by turbulent diffusion caused by fluid movement and substrate concentration profile in biofilm was calculated. An experiment was carried out to measure velocity profile near a biofilm under oscillatory flow conditions and the influence of the turbulence on substrate uptake rate by the biofilm was also measured. Measured turbulence was in good agreement with the calculated one and the influence of the turbulence on the substrate uptake rate was well explained by the simulation.

scholarly journals Optimization of the flow conditions in the spawning ground of the Chinese sturgeon (Acipenser sinensis) through Gezhouba Dam generating units

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anyang Huang ◽  
Jinzhong Yao ◽  
Jiazhi Zhu ◽  
Xingchen Gao ◽  
Wei Jiang
Keyword(s):  
Spawning Ground ◽  
Chinese Sturgeon ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Acipenser Sinensis ◽  
Critically Endangered Species ◽  
Gezhouba Dam ◽  
Opening Mode ◽  
Suitable Area ◽  
Good Agreement

AbstractChinese sturgeon (Acipenser sinensis) is a critically endangered species, and waters downstream from Gezhouba Dam are the only known spawning ground. To optimize the velocity conditions in the spawning ground by controlling the opening mode of Gezhouba Dam generator units, a mathematical model of Chinese sturgeon spawning ground was established in FLOW-3D. The model was evaluated with velocity measurements, and the results were determined to be in good agreement. By inverting the 2016–2019 field monitoring results, the model shows that the preferred velocity range for Chinese sturgeon spawning is 0.6–1.5 m/s. Velocity fields of different opening modes of the generator units were simulated with identical discharge. The suitable-velocity area was maximal when all units of Dajiang Plant of Gezhouba Dam were open. For discharges below 12,000 m3/s, most of the area was suitable; for discharges above 12,000 m3/s, the suitable area rapidly decreased with increasing discharge. A comparison of suitable areas under high-flow showed that at discharges of 12,000–15,000 m3/s, opening 11–13 units on the left side was optimal. For discharges above 15,000 m3/s, all units should be open. We used these results to recommend a new operation scheme to support the conservation of Chinese sturgeon.

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