The Effect of Different Turbulence Models on the Emitter Discharge by Using Computational Fluid Dynamics

2013 ◽  
Vol 662 ◽  
pp. 586-590
Author(s):  
Gang Lu ◽  
Qing Song Yan ◽  
Bai Ping Lu ◽  
Shuai Xu ◽  
Kang Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Turbulence Models ◽  
Experimental Results ◽  
Turbulent Model ◽  
Simulation Results ◽  
Rsm Model ◽  
Dynamics Method ◽  
Emitter Discharge

Four types of Super Typhoon drip emitter with trapezoidal channel were selected out for the investigation of the flow field of the channel, and the CFD (Computational Fluid Dynamics) method was applied to simulate the micro-field inside the channel. The simulation results showed that the emitter discharge of different turbulent model is 4%-14% bigger than that of the experimental results, the average discharge deviation of κ-ω and RSM model is 5, 4.5 respectively, but the solving efficiency of the κ-ω model is obviously higher than that of the RSM model.

scholarly journals CFD Study on Impeller Effect on Mixing in Miniature Stirred Tank Reactor

CFD letters ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 15-26
Author(s):  
Adnan Ghulam Mustafa ◽  
Mohd Fadhil Majnis ◽  
Nor Azyati Abdul Muttalib
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Calcium Alginate ◽  
Alginate Beads ◽  
Experimental Results ◽  
Stirred Tank ◽  
Stirred Tank Reactor ◽  
Calcium Alginate Beads ◽  
Tank Reactor ◽  
Simulation Results

Mixing of fluid can happen in existence or absence of impeller which will affect the mixing performance. The hydrodynamics behavior of fluid has a strong effect on the mixing. The design of mixing systems and operation using the agitated tanks is complicated because it is difficult to obtain accurate information for turbulence’s impeller induced. Computational Fluid Dynamics can be used to provide a detailed comprehension of those systems. This paper describes the effect of various designs of impeller in miniature stirred tank reactor towards the mixing of the calcium alginate beads with the milk using Computational Fluid Dynamics (CFD) software, ANSYS Fluent 19.2. The four different type of impellers are edge beater, 5-turbine blade, t-shape, and paddle. The impeller was simulated at different speeds of 150 rpm, 250 rpm, and 300 rpm. K-epsilon turbulence model was employed to simulate the flow distribution pattern of calcium alginate beads and the Multiple Reference Frame approach was used for the impeller rotation’s simulation. The simulation results obtained have a good agreement with the experimental results in term of vortex formation. The simulation results obtained for contour plots were fitted well with the experimental results as well as with pattern of impeller flow which was also studied. As a result, an optimal design of the impeller that is able to produce good mixing can be achieved using CFD analysis. The results obtained after performing the simulation proved that edge beater blade outperformed the other impellers and took the least time to fully distribute the calcium alginate beads in the tank at 250 rpm compared to 150 and 300 rpm. It can also be concluded that the edge beater blade is the best for the mixing of two-phase fluid and also produces mixed pattern flow. The obtained results from CFD can also be used to scale up the mixing process in larger systems.

Simulation of the Effect of Process Parameters on Particle Velocity in Cold Spray Using Laval Nozzle with Nine Holes

2011 ◽  
Vol 314-316 ◽  
pp. 78-81
Author(s):  
Chuan Shao Liu ◽  
Yao Hui Jin ◽  
Jian Xin Zheng
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Supersonic Flow ◽  
Flow Field ◽  
Particle Velocity ◽  
Laval Nozzle ◽  
Particle Diameter ◽  
Standoff Distance ◽  
Single Hole ◽  
Dynamics Method

Simulations of the supersonic flow field inside and outside of the Laval nozzle with single hole and nine holes were carried out based on the computational fluid dynamics method. The effects of different standoff distance and particle diameter on impact velocity of Cu particle spraying from single hole and nine holes were investigated firstly. The results show that the particle velocity obtained with the nine holes nozzle is higher than that of the single hole nozzle under the same standoff distance, and the smaller the standoff distance, the higher the particle velocity may be obtained with the nine holes, and the higher particle velocity may be obtained with smaller particle diameter for particles with diameters of 1 ~ 15 μm. Furthermore the effects of different spraying pressure and temperature on particle velocity of Cu particle spraying from the nine holes nozzle were also studied. And the simulations indicate that the higher the spraying pressure and temperature may make the particle spraying with greater velocity.

Simulation of Combustion Process in Diesel Engines Based on Eddy Dissipation Model

2016 ◽  
Vol 823 ◽  
pp. 315-318
Author(s):  
Mahran Dawwa
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Combustion Chamber ◽  
Diesel Engines ◽  
Combustion Process ◽  
Premixed Combustion ◽  
Dissipation Model ◽  
Simulation Results ◽  
Dynamics Method

The aim of this study is to simulate the combustion process in the combustion chamber of diesel engines by using eddy dissipation model (EDM) and computational fluid dynamics method (CFD). Computational fluid dynamics has been used wieldy in the recent years for simulating the strokes of diesel engines including the combustion process. Eddy dissipation model can be used for simulating non-premixed combustion cases such as the combustion in diesel engines. The simulation steps and the simulation results will be discussed and illustrated. ANSYS program is the software which used for performing this simulation.

scholarly journals Numerical investigations on effect of wear-ring clearance on performance of a submersible well pump

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770415 ◽  
Author(s):  
Weidong Shi ◽  
Xiongfa Gao ◽  
Qihua Zhang ◽  
Desheng Zhang ◽  
Daoxing Ye
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Reverse Flow ◽  
Internal Flow ◽  
Experimental Results ◽  
Ring Size ◽  
Numerical Investigations ◽  
Calculation Results

A typical submersible well pump was investigated in this article. The whole flow field of submersible well pump was numerically simulated by computational fluid dynamics software. The influence of clearance of wear-rings on the external characteristic and internal flow field was analyzed through comparing the calculation results with experimental results. The result of the numerical simulation shows that changing clearance of front wear-ring has a greater impact on pump performances than changing clearance of back wear-ring, and the head and efficiency of pump decrease with the increase in the size of clearance. Especially when the size of clearance is larger than 0.5 mm, decreasing becomes more obvious. When the front and back wear-ring size of the clearance comes to 1.0 mm, the efficiency decreases from the highest point of 75.31% to 65.44% at rated flow, and the head of pump decreases about 3.5 m. When the size of clearance is 0.2 mm, reverse-flow will appear in the front shroud cavity of the impeller, and leakage from back wear-ring through the balance hole into the impeller, which has a little influence on the flow field of the impeller inlet.

Numerical Simulation of the Inner Flow Field and the Optimal Design of Hema-Type ATY Nozzle Based on Fluent

2013 ◽  
Vol 634-638 ◽  
pp. 3774-3777
Author(s):  
Min Hua Zhang ◽  
Hong Mei Zheng ◽  
Cui Liu ◽  
Yin Hu Qu ◽  
Tao Liang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Optimal Design ◽  
Flow Field ◽  
Flow Fields ◽  
Fluent Software ◽  
Simulation Results

the inner flow fields of twelve Hema-type ATY nozzles which have different structure and parameters are simulated by the Fluent software, which is based on the CFD (Computational Fluid Dynamics) theory.Then the simulation results are analyzed，through wich the best designed nozzle is determined.

scholarly journals Improvement of Aerodynamic Performance of Savonius Wind Rotor Using Straight-Arc Curtain

2020 ◽  
Vol 10 (20) ◽  
pp. 7216
Author(s):  
Hongfu Zhang ◽  
Zhiqiang Li ◽  
Dabo Xin ◽  
Jian Zhan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Mean Power ◽  
Negative Moment ◽  
Dynamic Performances ◽  
Dynamics Method ◽  
Static Torque

A straight and an arc-shaped curtain are combined to enhance the aerodynamic performance of the Savonius wind rotor. The straight-arc curtain is placed in front of the Savonius wind rotor to reduce the negative moment on the convex blade and increase the positive moment on the concave blade. The static and dynamic performances of the Savonius wind rotor with and without the curtain are investigated based on the computational fluid dynamics method. The results show that the static torque is higher with the curtain than without it at the same angle-of-attack. The maximum mean power coefficient with the curtain is increased by about 50% compared with conventional Savonius wind rotor. Additionally, the flow field around the rotor with the straight-arc curtain is presented, and the flow control mechanics of the straight-arc curtain are discussed.

Computational Fluid Dynamics Simulation about Comparison of Different Forms of Return Air in a Small Cold Store

2012 ◽  
Vol 516-517 ◽  
pp. 1133-1138 ◽  
Author(s):  
Yi Tang ◽  
Jing Xie ◽  
Jin Feng Wang ◽  
Chen Miao ◽  
Yi Zheng
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Finite Volume Methods ◽  
Dynamics Simulation ◽  
Wall Function ◽  
Computational Fluid Dynamics Simulation ◽  
Cold Store ◽  
Simulation Results

The quantity of the cold store in our country has been rapidly rising since the 1990s, however, the flow field in the cold store is difficult to obtain accurately by experiments. With reference to the experiences in previous numerical simulations in this paper, CFD is used for analyzing two forms of return air in the cold store with the Finite Volume Methods and the SIMPLE Revised. As a result, Combining with the non-equilibrium wall function, it is found that taking the way of return air on both sides of the fan is more reasonable and the cooling consumption of the empty cold store can be saved before the products enter the cold store. Furthermore, the numerical simulation results can provide reference for choosing fans in the small cold store.

scholarly journals Validation Study of Photovoltaic Thermal Nanofluid Based Coolant Using Computational Fluid Dynamics Approach

CFD letters ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 58-71
Author(s):  
Mohd Afzanizam Mohd Rosli ◽  
Yew Wai Loon ◽  
Muhammad Zaid Nawam ◽  
Suhaimi Misha ◽  
Aiman Roslizar ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Surface Temperature ◽  
Validation Study ◽  
Numerical Approach ◽  
Experimental Results ◽  
Thermal System ◽  
Outlet Temperature ◽  
Photovoltaic Thermal System ◽  
Simulation Results

In the study, the photovoltaic thermal system using nanofluid as coolant is validated using numerical approach by comparing the experimental results and simulation results. Due to high cost and difficulty in preparing nanofluid, it is more practical to perform the study using numerical approach which is convenient and saves plenty of time. The photovoltaic thermal system is investigated numerically through Computational Fluid Dynamics Approach using Ansys 19.0 Fluent Software. The numerical study is based on different solar irradiation at different hours. The coolant that is selected in the study is aluminum oxide () water nanofluid. The validation study between the experimental results and simulation results are achieved by examining the photovoltaic (PV) surface temperature and nanofluid outlet temperature. The maximum percentage of error between experimental and simulation results of PV surface temperature and nanofluid outlet temperature are 12.66% and 7.89%. Also, the mean average percentage error (MAPE) are computed for PV surface temperature and nanofluid outlet temperature. The results for PV surface temperature and nanofluid outlet temperature are 10.31% and 6.67%. Since the MAPE results are within 10% or error, it proved that there is good accuracy between the simulation and experimental results.

scholarly journals Assessment of Computational Fluid Dynamics Capabilities for the Prediction of Three-Dimensional Separated Flows: The DELFT 372 Catamaran in Static Drift Conditions

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
R. Broglia ◽  
S. Zaghi ◽  
E. F. Campana ◽  
T. Dogan ◽  
H. Sadat-Hosseini ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Separated Flow ◽  
Lateral Force ◽  
Separated Flows ◽  
Overlapping Grids ◽  
Wave Induced

In this paper, capabilities of state-of-the-art computational fluid dynamics (CFD) tools in the prediction of the flow-field around a multihull catamaran advancing in straight ahead motion at nonzero drift angles are investigated. CFD estimations have been provided by three research institutes by using their in-house codes: CNR-INM using Xnavis, IIHR using CFDShip-Iowa, and CNRS/ECN using ISIS. These allowed an in-depth comparison between different methodologies, such as structured overlapping grids versus unstructured grid, different turbulence models and detached eddy simulations (DES) approaches, and level-set (LS) versus volume of fluid (VoF). The activities were pursued within the NATO AVT-183 group “reliable prediction of separated flow onset and progression for air and sea vehicles,” aimed at the assessment of CFD predictions of large three-dimensional separated flows. Comparison between estimations is provided for both integral and local quantities, and for wave-induced vortices. Validation is reported by comparison against the available experimental fluid dynamics (EFD) data. Generally, all the simulations are able to capture the main features of the flow field; grid resolution effects are dominant in the onset phase of coherent structures and turbulence model affects the dynamic of the vortices. Hydrodynamic loads are in agreement between the submissions with standard deviation of about 3.5% for the resistance prediction and about 7% for lateral force and yaw moment estimation. Wave-induced vortices are correctly captured by both LS and VoF approaches, even if some differences have been highlighted, LS showing well-defined and long life vortices.

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