CFD Simulation of Internal Flow and Mixing within Droplets in a T-Junction Microchannel

Author(s):  
Xu Chao ◽  
Feishi Xu ◽  
Chaoqun Yao ◽  
Tingting Liu ◽  
Guangwen Chen
Keyword(s):  
2011 ◽  
Vol 339 ◽  
pp. 148-151 ◽  
Author(s):  
Shu Juan Zheng ◽  
Long Quan

This paper optimizes the structure of the poppet valve based on the internal flow. The flow-force on poppet valve in the case of the converging flow is simulated and studied by CFD. Simulation results represent that the traditional formula for computing the flow-force can be used only in the certain range, so the formula is modified based on the simulation result.


2012 ◽  
Vol 621 ◽  
pp. 196-199
Author(s):  
Shui Ping LI ◽  
Ya Li Yuan ◽  
Lu Gang Shi

Numerical simulation method of the internal flow field of fluid machinery has become an important technology in the study of fluid machinery design. In order to obtain a high-performance cement slurry mixer, computational fluid dynamics (CFD) techniques are used to simulate the flow field in the mixer, and the simulation results are studied. According to the analysis results, the structural parameters of the mixer are modified. The results show the mixer under the revised parameters meet the design requirements well. So CFD analysis method can shorten design period and provide valuable theoretical guidance for the design of fluid machinery.


2014 ◽  
Vol 644-650 ◽  
pp. 4682-4685
Author(s):  
Zhi Jian Wang ◽  
Tian Zhu Zhang ◽  
Jin Shang ◽  
Metsakeu Kong Evariste

In this paper, calculating fluid dynamics (CFD) method is utilized for analyzing the precision compound sand control screen internal flow field so as to establish appropriate models. During this numerical calculation, by using the - turbulence model is used to simulate the resistance characteristics under different working conditions when crude oil flows through precision compound sand control screen, analyze its speed change rule, flow path and pressure distribution, etc. The use of porous media model to simulate the resistance of the oil screen effect, the oil screen is replaced by the porous jump surface to simulate the strainer of pressure drop. To screen sand control performance and reduce the flow resistance to provide theoretical support, make the reservoir production losses to a minimum.


Author(s):  
G. V. Hobson ◽  
A. J. Gannon ◽  
R. P. Shreeve

The simulation of a transonic compressor stage is presented. This stage was designed using an Euler CFD code with the intent of minimizing the use of empirical design techniques. The stage has subsequently been built and tested. More recently an existing multi-block Navier-Stokes code with a steady averaging-plane to pass information between the blade rows was used to simulate the flow through the machine. Performance maps of stage pressure ratio and efficiency at 70, 80, 90 and 100% speeds from both the Euler and Navier-Stokes CFD codes are compared with the experimental results. Details of the internal flow from the Navier-Stokes code are presented. Comparison of the design Euler CFD and experimental results showed reasonable agreement and validated its use as a design tool. Agreement between experimental and the current Navier-Stokes CFD results was good, allowing the code to be used in the viewing of the internal flow field. Improvements to the initial design CFD method are discussed in light of the experimental program and more recent simulations.


2011 ◽  
Vol 418-420 ◽  
pp. 2006-2011
Author(s):  
Rui Zhang ◽  
Cheng Jian Sun ◽  
Yue Wang

CFD simulation and PIV test technology provide effective solution for revealing the complex flow of hydrodynamic coupling’s internal flow field. Some articles reported that the combination of CFD simulation and PIV test can be used for analyzing the internal flow field of coupling, and such analysis focuses on one-phase flow. However, most internal flow field of coupling are gas-fluid two-phase flow under the real operation conditions. In order to reflect the gas-fluid two-phase flow of coupling objectively, CFD three-dimensional numerical simulation is conducted under two typical operation conditions. In addition, modern two-dimensional PIV technology is used to test the two-phase flow. This method of combining experiments and simulation presents the characteristics of the flow field when charging ratios are different.


Author(s):  
Jian Ge ◽  
Wenxi Tian ◽  
Tingting Xu ◽  
Jiesheng Min ◽  
Guofei Chen ◽  
...  

The coolant flow in the reactor pressure vessel (RPV) lower plenum is complex due to the presence of various internal structures, which has a great influence on the flow distribution at the core inlet. In order to study the thermal hydraulic characteristics in the RPV lower plenum, many scaled down test facilities have been built for different PWR reactors such as Juliette, ACOP, and ROCOM. Although the experimental study is still a main research method, it may be not economical in some situations due to the high cost and the long study period. Compared with the experimental method, Computational Fluid Dynamics (CFD) methodology can simulate three dimensional fluid flow in complex geometries and perform parametric studies more easily. The detailed and localized thermal hydraulic characteristics which are difficult to measure during experiments can be obtained. So CFD simulation has been widely used nowadays. One of the purposes of numerical simulations of the internal flow in a RPV is to get the flow distribution at the core inlet, then to make an optimization for the flow diffusor in the RPV lower plenum to improve the core inlet flow distribution homogeneity. Appropriate optimizations for the flow diffusor depends on fully understanding the flow phenomena in the RPV lower plenum. In this paper, Phenomenon Identification and Ranking Table (PIRT) is adopted to analyze the physical phenomenon that occurs in the RPV lower plenum with the typical 900MW reactor internal structures, and the importance of the various physical phenomena and the reference parameters are ranked through expert opinions and literature review. Then a preliminary three dimensional CFD simulation for the reactor vessel is conducted. The main phenomena identified by the PIRT can be observed from the simulation results.


2019 ◽  
Vol 118 ◽  
pp. 02047
Author(s):  
Hongguang Zhu ◽  
Rui Jing

The anaerobic fermentation produces biogas with the participation of sensitive microorganisms. The smooth fermentation needs to ensure good heat transfer and mass transfer effects. Stirring is very important to create these fermentation conditions. In this paper, the computational fluid dynamics method is used to simulate the flow field inside a fully-mixed stirred anaerobic reactor. It is divided into a single-layer six-leaf open-type turbine with baffles and two-layer four-leaf inclined 45-degree paddles. Group conditions, and quantitative calculation and analysis of the internal flow field of the simulated reactor. The effects of different blades and different stirring speeds are investigated. The results show that the double-layer oblique upward paddle can produce a better axial velocity distribution, which is more conducive to the formation of a large fluid loop structure that circulates up and down. The average speed of double-layer agitation at 125-320 rpm is less than the average speed of a single layer, but the speed of double-layer agitation at 60 rpm is greater than the speed of a single layer.


2014 ◽  
Vol 535 ◽  
pp. 495-499
Author(s):  
Jing Song ◽  
Wei He ◽  
Zhe Kun Li ◽  
Wen Li Shi

Analyzed the research status of hydrocyclone separation. By using CFD software, the important parameters of velocity and pressure in the hydrocyclone are analyzed and contrasted. Through simulation, it can accurately reflect the internal flow field, and can be used to predict the hydrocyclone separation performance. The results of flow field simulation will help to finish structure design of hydrocyclone and to provide the basis for the optimization design of hydrocyclone.


Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Geoffrey Guindeuil ◽  
Theodoros Lekas ◽  
Vassilios Pachidis

This study refers to the development and validation of a Three Dimensional (3D) Vortex Lattice Method (VLM) to be used for internal flow case studies and more precisely aero-engine intake simulation. It examines the quantitative and qualitative response of the method to a convergent – divergent intake, produced as a surface of revolution of the CFM56-5B2 upper lip geometry. The study was carried out for three different sections namely: Intake outlet, intake throat and intake inlet. Moreover five different settings of Angle Of Attack (AOA) were considered. The VLM was based on an existing code. It was modified to accommodate internal flow effects and match, as closely as possible, the boundary conditions set by the Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) simulation. In the context of this study, Vortex Lattice-derived average values velocity profiles were compared against RANS CFD results.


Author(s):  
Hong-Jie Wang ◽  
Ru-Zhi Gong ◽  
De-Ping Lu ◽  
Zhong-De Wu ◽  
Feng-Chen Li

Thrust bearing is a key component of large-scale water turbine. It closely relates to the efficiency of large-scale water turbines, and even determines whether the large-scale turbine can operate normally. With the development of the capacitance of water turbines, thrust bearing will develop to the direction of high speed and heavy load. The structure, strength, lubrication and the characteristic of heat radiation of large-scale thrust bearing were often researched in the past. To study the flow condition of the large-scale thrust bearing and analyze the load characteristics, CFD simulation was carried out on the model of thrust bearing. In this study, CFD method was used to simulate the internal flow field of the large-scale thrust bearing. The model researched was a thrust bearing for 1000MW water turbines. The diameter of the thrust bearing was over 5.8 meters, and the maximum thrust load of the bearing can reach to 60MN. The thin gap between the runner and the pad was usually neglected in the published CFD calculations of thrust bearing. But the thin gap was taken into account in this investigation. 1/12 of the model was used as the computational field and periodic boundary was used in the calculation. The standard κ-ε turbulence model was used to simulate the thrust bearing model, and the flow field in the thrust bearing was obtained. The thin gap between the runner and the pad is a wedge. The pressure and velocity distribution in the thrust bearing and thin gap was calculated respectively with conditions of different thin gaps and different rotational speeds of runner. After that, the relationship between carrying capacity and the size of clearance or the speed of the runner through analyzing the data has been obtained from the results of the calculation.


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