Three-dimensional Fluid Simulation Research Articles

Bio-Inspired Textiles for Self-Driven Oil-Water Separation-A Simulative Analysis of Fluid Transport.

In addition to water repellency, superhydrophobic leaves of plants such as Salvinia molesta adsorb oil and separate it from water surfaces. This phenomenon has been the inspiration for a new method of oil-water separation, the bionic oil adsorber (BOA). In this paper, we show how the biological effect can be abstracted and transferred to technical textiles, in this case knitted spacer textiles hydrophobized with a layered silicate, oriented at the biology push approach. Subsequently, the transport of the oil within the bio-inspired textile is analyzed by a three-dimensional fluid simulation. This fluid simulation shows that the textile can be optimized by reducing the pile yarn length, increasing the pile yarn spacing, and increasing the pile yarn diameter. For the first time, it has been possible with this simulation to optimize the bio-inspired textile with regard to oil transport with little effort and thus enable the successful implementation of a self-driven and sustainable oil removal method.

Three-dimensional fluid simulation of a planar coil inductively coupled argon plasma source for semiconductor processes

In this paper, the effect of the coil structure, as well as the gas pressure, on the spatial distribution of an inductively coupled argon plasma is numerically investigated based on our developed three-dimensional fluid model. The model is based on a modified ambipolar diffusion model, in which the electron density is solved under the quasi-neutral condition, the ion density and neutral particle density are obtained by solving continuity equations, and the ion flux is achieved by solving the full momentum balance equation. In addition, the inductive electric field is governed by the Maxwell equations, which are solved in the frequency domain. The results show that the electron density is nonuniform along the azimuthal direction due to the asymmetry of the coil structure, and the uniformity becomes better as gas pressure decreases. Besides, the plasma azimuthal uniformity can also be improved by reducing the opening of the coil. As the coil radius increases, the plasma density decreases, while the radial uniformity of the plasma improves, and the azimuthal uniformity deteriorates. In addition, the influence of the current amplitude ratio between the inner coil and outer coil on the plasma uniformity in dual-coil discharge is also investigated. It is found that the plasma radial uniformity becomes better by reducing the inter-to-outer coil current amplitude ratio. The results obtained in this work demonstrate that the plasma uniformity can be improved by optimizing the coil structure and adjusting the discharge parameters, which is of significant importance in etching and deposition processes.

Analysis on influence of self-fan cooling motor on fan aerodynamics

With the development of multi electric/all electric aircraft, the degree of aircraft secondary energy electrification is becoming higher and higher. As the core component of the electrical system, the motor presents the trend of small volume and high-power density. The heat dissipation problem of compact motor is becoming more and more serious. At present, the self-driven fan cooling system is widely used in aircraft motors. In this paper, the axial fan cooling system of an aero generator is taken as the research object, and the changes of fan flow field and aerodynamic characteristics in the fan motor coupling model of the isolated fan and the installed motor are analyzed by using three-dimensional computational fluid simulation. At the same time, the influence of the change of the axial distance between the fan and the motor on the aerodynamic performance is also studied. The analysis of the simulation results shows that the close coupling between the motor and the fan components greatly affects the flow structure in the fan, resulting in the distortion potential effect on the fan outlet section. The fan flow field appears the blade root reflux, the channel vortex in the blade and the expansion of the corner separation area. With the increase of the axial distance between the motor and the fan, the influence of the motor on the flow in the fan gradually approaches the flow blocking effect.

Influence of Diffuser Vane Thickness on Centrifugal Compressor Performance

The structure of diffuser vanes has a significant influence on the performance of centrifugal compressors. To research the influence of diffuser vane thickness on the overall performance and internal flow condition of the centrifugal compressor. This paper takes a centrifugal compressor as the research object. By changing the diffuser vane thickness, and using three-dimensional fluid simulation technology to carry out simulation research. The results show that the thinner diffuser vanes can greatly improve the efficiency, flow rate and outlet temperature of the centrifugal compressor. For internal local fluid characteristics, thin diffuser blades have lower internal heat load. However, the local flow of fluid is not consistent with the change of vane thickness.

Research on Momentum Parameters of Tailings Dam-break Mortar

The tailings dam-break mortar with high potential energy will cause impact damage to the downstream buildings, and the momentum parameters of mortar can effectively reflect its impact on buildings. Taking the distribution status of downstream geomorphology and production and living facilities of Yangjiawan tailing pond as the calculation background, Numbering 4 sensitive analysis points from 1 to 4 in line with the distance between the key protected structures and the breach of the tailing pond from the near to the distant, The three-dimensional fluid simulation software FLOW 3D was used to simulate the evolution process of dam-break mortar under the full-break condition of the accumulation dam above the initial dam, and the variation characteristics of the flow mortar momentum at the key protection structures in the evolution process were analyzed. The results show that the momentum of dam-break mortar at the sensitive points decreases from the near to the distant, Compared with instantaneous momentum, cumulative momentum could reflect the cumulative impact effect of mortar on buildings, and the distinction of impact effect was more obvious.; The peak inundation depth of dam-break mortar at each sensitive point was 1, 3, 2 and 4 sensitive points in descending order, the momentum and submergence depth were inconsistent, The momentum could clearly distinguish the difference of mortar impact effect, and the research results could provide some reference for dam - breaking mortar disaster assessment of tailing pond

Evaluation of heat dissipation characteristics of quantum cascade laser with diamond submount using structure function and three-dimensional thermal fluid simulation

The heat dissipation of a quantum cascade laser (QCL) for a mounted structure with and without a diamond submount was evaluated by temperature and structure function measurements and three-dimensional simulation. From the structure function, it was shown that the thermal resistance between the QCL on the InP substrate and the CuW mount was reduced from 5.0 K W−1 without the submount to 2.5 K W−1 with the diamond submount. In the 3D simulation, it was confirmed that the heat flux transmitted horizontally through the diamond mount is larger than that without the submount. It is considered that the heat flux in the horizontal direction improved the heat dissipation from the InP substrate to the CuW mount. As a result, the output of the QCL with the submount was 1.15 times that of the QCL without the submount.

Three Dimensional Fluid Simulation and Experimental Verification of Hydrostatic Guideway for Large Rotary Worktable

Relying on the major national science and technology special project, this study used the table 12 fan-shaped oil cavity hydrostatic guideway of CKS5235 CNC vertical lathe worktable, applied FLUENT processing software GAMBIT modeling and mesh generation the flow static pressure guide film, setting boundary conditions. Used simulation software FLUENT numerical analysis the dynamic process of hydrostatic slideway oil film flow field with temperature field and the basic bearing capacity, the effectiveness of three dimensional fluid simulation method for hydrostatic guideway in engineering design is verified by experiments. According to the results of three-dimensional fluid simulation, the hydrostatic guide structure of CKS5235 CNC vertical lathe worktable has been improved, achieve the speed performance improvement of the table, complete the major special technical research and acceptance.

Multiobjective Optimization Design of Double-Row Blades Hydraulic Retarder with Surrogate Model

For the design of double-row blades hydraulic retarder involves too many parameters, the solution process of the optimal parameter combination is characterized by the large calculation load, the long calculation time, and the high cost. In this paper, we proposed a multiobjective optimization method to obtain the optimal balanced solution between the braking torque and volume of double-row blades hydraulic retarder. Moreover, we established the surrogate model for objective function with radial basis function (RBF), thus avoiding the time-consuming three-dimensional modeling and fluid simulation. Then, nondominated sorting genetic algorithm-II (NSGA-II) was adopted to obtain the optimal combination solution of design variables. Moreover, the comparison results of computational fluid dynamics (CFD) values of the optimal combination parameters and original design parameters indicated that the multiobjective optimization method based on surrogate model was applicable for the design of double-row blades hydraulic retarder.

Effect of deformed interface on hydro-viscous drive characteristics

In this article, the effect of the deformed interface on the hydro-viscous drive characteristics was investigated through a three-dimensional fluid simulation and experiments. The main parameters such as pressure field, velocity field, and torque transferred by the oil film were simulated in FLUENT software in the light of the principle of the computational fluid dynamics. The results found that the dynamic pressure and velocity of the oil film goes up gradually along the radial direction, and the dynamic pressure at zone with groove is much higher than that without groove due to the hydrodynamic effect. After the interface deforming, the dynamic pressure decreases; while the torque transferred by the oil film increases slightly. Furthermore, a special hydro-viscous drive test-bed was developed to verify the correctness and validity of the theoretical results.

C201 3次元流体解析による陸上を遡上する津波の評価(OS8 軽水炉・新型炉・原子力安全)

C201 3次元流体解析による陸上を遡上する津波の評価(OS8 軽水炉・新型炉・原子力安全)

Three-dimensional fluid simulations on a line-shaped microwave plasma

A three-dimensional (3D) fluid simulation code has been developed to investigate the discharge characteristics and plasma distribution in a line-shaped microwave plasma device, which consists of a rectangular waveguide with a variable width a, a long quartz discharge tube with a U-shaped cross section partly inserted into the waveguide and the plasma diffusion chamber. The line-shaped plasmas are mainly produced just under the discharge tube surrounded by the complex structure. Experiments have revealed that the axial profile of the plasma density ne can be changed when a and the insertion depth di of the discharge tube into the waveguide are varied. 3D numerical analyses show that the axial distribution of power absorption Pabs depends on a and di and concentrates near the single side of the discharge tube when the high-ne plasma is inserted deeply into the waveguide. 3D simulations show that ne has peaks near the inner edges of the discharge tube and the axial distribution of ne depends on the waveform of the electric fields formed in the waveguide. The change in density profiles due to the variation of a and di observed in the experiment is mostly reproduced qualitatively by the present 3D simulation.

A Study on Actual Conditions of Thermal Environment and Indoor Air Quality in a Japanese Traditional House Corresponding to Sericulture

This study of the traditional sericulture residence, located inside the Minkaen, Jidayubori Park, Setagaya Ward, Tokyo, Japan, aims to clarify the environmental characteristics of a sericulture building from the engineering point of view. In sericulture, the silkworms are raised at different locations depending on their age. Therefore we describe the actual conditions of the thermal environment such as temperature and humidity when the silkworm is breeding, and the air quality such as CO2, CO, VOC, and carbonyl compound from the silkworm hearth. In addition to these factors the ventilation rate in each part of the traditional house corresponding to sericulture is determined. Moreover, the ventilation performance of the attic and the monitor roof is investigated. The mechanism of thermal conditions, IAQ and ventilation rate was clarified in this paper for the first time using the three-dimensional heat fluid simulation software. As described thus far, we have clarified the environmental situation in a sericulture house from the engineering point of view.

Discharge characteristics of a plasma display panel with hump-shape electrodes

The long gap discharge in a plasma display panel has an advantage of high luminous efficacy but has a deficiency of high firing voltage as well. A hump-shape electrode is suggested to reduce the firing voltage of a long gap discharge while maintaining high luminous efficacy. The effects of hump electrodes inserted between two sustain electrodes are investigated by experiment and with a three-dimensional fluid simulation. The experimental results show that hump structure has lower firing and sustain voltage than the conventional long gap structure. A three-dimensional fluid simulation shows that the hump electrode enhances discharge ignition while maintaining the same optical characteristics of the long gap discharge. Also, the hump structure guarantees the addressing reliability with a reduced discharge time lag.

Three-Dimensional Computational Fluid Simulation of Diesel and Dual Fuel Engine Combustion

A 3D computational fluid dynamics model with a reduced detailed chemical kinetics of the combustion of diesel and methane fuels is developed while considering turbulence during combustion to simulate the mixture flow, formation, and combustion processes within diesel and diesel/methane dual fuel engines having swirl chambers. The combustion characteristics of the pilot injection into a small prechamber are also investigated. Modeled results were validated by a group of corresponding experimental data. The spatial and temporal distributions of the mixture temperature, pressure, and velocity under conditions with and without liquid fuel injection and combustion are compared. The effects of engine speed, injection timing, and the addition of carbon dioxide on the combustion process of dual fuel engines are investigated. It is found that in the absence of any fuel injection and combustion, the swirl center is initially formed at the bottom-left of the swirl chamber, and then moved up with continued compression in the top-right direction toward the highest point. The swirling motion within the swirl and main combustion chambers promotes the evaporation of the liquid pilot and the combustion processes of diesel and dual fuel engines. It was observed that an earlier autoignition can be obtained through injecting the pilot fuel into the small prechamber compared with the corresponding swirl chamber operation. It is to be shown that reduced engine emissions and improved thermal efficiency can be achieved by a two-stage homogenous charge compression ignition combustion.

ACTUAL CONDITIONS AND THE MECHANISM OF THERMAL ENVIRONMENT AND INDOOR AIR QUALITY IN A TRADITIONAL HOUSE CORRESPONDING TO SERICULTURAL BUILDINGS

This paper describes the actual conditions of thermal environment when silkworm is breeding, and the air quality such as CO2, CO, VOC, carbonyl compound whose hearth is used. In addition to those factors ventilation rate in each part of the traditional house corresponding to sericulture are found out in Setagaya Ward Jidaiyubori Park. Moreover, the ventilation performance in back of the ceiling and the monitor roof is investigated. The mechanism of thermal conditions, IAQ and ventilation rate was clarified in this paper for the first time using the three-dimensional heat fluid simulation software.

Three-dimensional fluid simulation of a plasma display panel cell

In order to understand the discharge characteristics in an alternating current plasma display panel (ac PDP) and optimize it further, a three-dimensional fluid code (FL3P) has been developed. Using this simulator, various three-dimensional features of discharges are investigated in the sustain mode of PDP. First, the striations of wall charge are observed at both the anode and cathode side. Second, the local efficiency is obtained as a function of position. It is mainly divided into the anode region and the cathode region and highest near the anode center. Finally, the effects of various three-dimensional parameters are studied. As one of the examples showing the effect of electrode shaping, the discharge characteristics of a T-shaped electrode cell are compared with those of a conventional cell. The phosphor on barrier ribs contributes to over 44% of the total luminance, but barrier ribs themselves do not play an important role in the overall discharge efficiency. Address electrode width is not always proportional to the size of the discharge because of the wall loss of the particles to barrier ribs.

Three-dimensional fluid simulation of an AC-PDP cell

Using a three-dimensional fluid model, we present top-views of AC-PDP cells with three different electrode shapes-a conventional electrode cell, a T-shaped electrode cell, and an asymmetric electrode cell. Figures include the contours of consumed power and photon generation power that are time averaged over the half period and space averaged over the direction that is not shown.

Three-dimensional stabilization mechanism for the auroral Farley-Buneman instability

The auroral ionospheric E-region supports at least two types of plasma irregularities: the gradient drift instability and the Farley-Buneman instability. These are driven by the electron density gradient and the electric field, respectively. In this paper we study the effect of the three-dimensional auroral geometry on the saturation of the instabilities. For that purpose, an exact stationary solution to the two-fluid plasma model equations is derived. The stationary state thus obtained is used as an initial condition of a three-dimensional nonlinear fluid simulation. The algorithm is also described. In the auroral zone, the collision frequencies have gradients along the magnetic field. This implies that the phase velocity of the plasmons depends on the altitude, which in turns causes wave propagation at a nonzero aspect angle. These waves are more damped than exactly perpendicular ones. From this it is no surprise that our three-dimensional code can be used even when the electric field is near the Farley-Buneman threshold value. On the contrary, two-dimensional fluid algorithms blow up when the electric field is that large. We also conclude that the height profiles of the electric field, the electron density and the collision frequencies all affect coherent radar spectra, alongside with the local value of the electric field.