scholarly journals Hydraulic analysis of gate valve using computational fluid dynamics (CFD)

2020 ◽  
Vol 29 (3) ◽  
pp. 275-288
Author(s):  
Elvis Žic ◽  
Patrik Banko ◽  
Luka Lešnik

As a very important element of most water supply systems, valves are exposed to the effects of strong hydrodynamic forces. When exposed to large physical quantities, the valve and piping can be damaged, which could endanger the performance of a water supply system. This is the main reason why it is necessary to foresee and determine the maximum values of velocity, pressure and other physical quantities that can occur in the system under certain conditions. Predicting extreme conditions allows us to correctly size the valve for the expected conditions to which the valve might be exposed, which is also the main objective of this paper. One of the methods for predicting and determining extreme values on a valve is to perform a simulation with computational fluid dynamics (CFD). This is exactly the method used in the preparation of this paper with the aim of gaining insight into the physical magnitudes for models of gate valves positioned inside a pipe under characteristic degrees of valve closure. The Ansys CFX 19.1 and Ansys Fluent 19.1 software was used to simulate the hydrodynamic analysis and obtain the required results. The hydrodynamic analysis was performed for four opening degrees of gate valve

2012 ◽  
Vol 220-223 ◽  
pp. 1698-1702
Author(s):  
Jian Chen ◽  
Zhu Ming Su ◽  
Qi Zhou ◽  
Jian Ping Shu

A novel hydraulic rotary high speed on/off valve is investigated. The function of the outlet turbine and the effect on revolution speed of valve spool are analyzed. The inner fluid flow condition under full open case of the on/off valve is simulated using computational fluid dynamics(CFD) method based on Ansys/Fluent and velocity and pressure profiles of fluid inside valve are obtained. Suggestions on optimizing the geometry of valve to decrease transition losses are given.


2021 ◽  
Vol 23 (2) ◽  
Author(s):  
Elin Yusibani ◽  
Hidayatun Nisa ◽  
Rajibussalim Rajibussalim

Penelitian ini bertujuan untuk mensimulasikan distribusi temperatur dengan variasi radius channel garam dan temperatur masukan pada teras Molten Salt Breeder Reactor (MSBR). Computational Fluid Dynamics (CFD) dengan perangkat lunak Ansys Fluent digunakan pada simulasi ini untuk sebuah sel moderator. Variasi radius channel garam adalah 0,0108 m; 0,0208; dan 0,0308 m dengan panjang moderator 3,96 m. Variasi temperatur masukan adalah 809 K, 839 K, 859 K, dan 909 K. Hasil simulasi pada variasi radius menunjukkan bahwa dengan pertambahan sebesar 0,01 m memberikan kenaikan suhu sebesar 8 - 23 K pada temperatur masukan konstan. Perubahan terhadap temperatur masukan, diperoleh kenaikan temperatur keluaran antara 1 - 10 K, pada radius channel garam yang konstan. Dengan demikian dapat disimpulkan bahwa distribusi temperatur dalam teras MSBR akan meningkat jika radius channel garam diperkecil atau temperatur masukan dinaikkan.


2019 ◽  
Vol 19 (3) ◽  
pp. 345-447
Author(s):  
Luong Ngoc Loi ◽  
Nguyen Chi Cong ◽  
Ngo Van He

In this work, the commercial Computational Fluid Dynamics (CFD), ANSYS-Fluent V.14.5 has been used to illustrate the effects of rudder and blade pitch on hydrodynamic performances of a propeller. At first, the characteristic curves of a container ship propeller are computed. Then, effects of rudder on hydrodynamic performances of the propeller in the both cases of the propeller with and without rudder have been investigated. The relationships between the blade pitch angle and the hydrodynamic performances of the selected referent propeller in this work having designed conditions as diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m and the boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller, pressure distribution, velocity distribution around propeller and the efficiency of the propeller have been shown. From the obtained results, the effects of rudder and blade pitch angle on hydrodynamic performances of the propeller have been evaluated.


2020 ◽  
Vol 44 (6) ◽  
pp. 599-611
Author(s):  
Arzu YAZGI ◽  
Vedat DEMİR ◽  
Adnan DEĞİRMENCİOĞLU

The objective of this study was to compare computational fluid dynamics (CFD)-based simulations and visualized seed trajectories in different seed tubes that can provide seed incorporation into the soil with enhanced seed spacing. The other objective was to determine the relation between the seed trajectories and peripheral speed of the vacuum disk. In order to meet the first objective, 2 different seeds (corn and cotton) and artificial spherical material (Ø10 mm) were tested under laboratory conditions. The seeds and artificial material were released by free fall into the semitransparent seed tubes (seed tubes A and B) from different release points, and their trajectories were recorded using a video camera. For the second objective, corn seeds were used and released from a vacuum-type metering unit equipped with a semitransparent seed tube (seed tube A) at 3 different peripheral speeds of the vacuum disk, as a function of 3 forward speeds of the seeder. For both objectives, the seed tubes were modeled and release of the seeds into the seed tubes was simulated and analyzed using ANSYS Fluent for CFD. The results obtained from the captured video and simulations were compared. As a result of the comparisons, it was found that the seed release point was an effective parameter on both the seed trajectory and seed spacing, since seed bouncing and skating in the seed tube, based on the release point, may occur. The results also showed that the lab tests and simulations were found to be very similar in terms of the seed trajectories and seed spacings. It is believed that this study, using CFD, will be an example and enable the development and design of new seed tubes in order to obtain better seed distribution uniformity.


Author(s):  
Jian Qi An ◽  
◽  
Kai Peng ◽  
Wei Hua Cao ◽  
Min Wu ◽  
...  

This paper aims at building a Computational Fluid Dynamics (CFD) model which can describe the gas flow three dimensions (3D) distribution in blast furnace (BF) throat. Firstly, the boundary conditions are obtained by rebuilding central gas flow shape in BF based on computer graphics. Secondly, the CFD model is built based on turbulent model by analyzing the features of gas flow. Finally, a method which can get the numerical solutions of the model is proposed by using CFD software ANSYS/FLUENT. The proposed model can reflect the changes of the gas flow distribution, and can help to guide the operation of furnace burdening and to ensure the BF stable and smooth production.


Author(s):  
Andrew Roberts ◽  
Ming-Chia Lai ◽  
Chi-Yang Cheng

The goal of this project was to develop a model for a Combined Photovoltaic/Thermal (PV/T) unit to ease in the assessment of potential changes to the unit before fabrication of actual parts. This process reduces the time to assess changes in the system; once the initial model is created changes are relatively simple. It also reduces cost incurred for actual testing by certified labs and can simulate output variations in different climate conditions, site locations and times of year. A commercially available PV/T unit was chosen for analysis, which utilizes two water channels under the photovoltaic assembly instead of the conventional sheet-and-tube design to actively cool the solar cells while also collecting thermal energy that can be used for heating water or air via a heat transfer system. The project described in this paper modeled the PV/T unit in two ways: (1) as a one-dimensional theoretical model and (2) modeling the system in ANSYS FLUENT and simulating the fluid flow, energy and radiation models using computational fluid dynamics (CFD). The baseline CFD model was correlated to published Solar Rating and Certification Corporation (SRCC) test data for pressure drop and thermal performance to gage accuracy of the model. Through a literature search of past work on similar modules and systems, several potential improvements to the unit were identified and a detailed analysis was conducted by individually adding each to the theoretical model, then comparing them to the output of the baseline model. Combinations of improvements were evaluated as well and assessed based on output improvement, technical feasibility and expected cost. The accuracy of the 1-D model was compared to the CFD model to assess the benefits gained from the added complexity of using computational fluid dynamics.


2015 ◽  
Vol 31 (1) ◽  
pp. 48-55 ◽  
Author(s):  
J. Paulo Vilas-Boas ◽  
Rui J. Ramos ◽  
Ricardo J. Fernandes ◽  
António J. Silva ◽  
Abel I. Rouboa ◽  
...  

The aim of this research was to numerically clarify the effect of finger spreading and thumb abduction on the hydrodynamic force generated by the hand and forearm during swimming. A computational fluid dynamics (CFD) analysis of a realistic hand and forearm model obtained using a computer tomography scanner was conducted. A mean flow speed of 2 m·s−1was used to analyze the possible combinations of three finger positions (grouped, partially spread, totally spread), three thumb positions (adducted, partially abducted, totally abducted), three angles of attack (a = 0°, 45°, 90°), and four sweepback angles (y = 0°, 90°, 180°, 270°) to yield a total of 108 simulated situations. The values of the drag coefficient were observed to increase with the angle of attack for all sweepback angles and finger and thumb positions. For y = 0° and 180°, the model with the thumb adducted and with the little finger spread presented higher drag coefficient values for a = 45° and 90°. Lift coefficient values were observed to be very low at a = 0° and 90° for all of the sweepback angles and finger and thumb positions studied, although very similar values are obtained at a = 45°. For y = 0° and 180°, the effect of finger and thumb positions appears to be much most distinct, indicating that having the thumb slightly abducted and the fingers grouped is a preferable position at y = 180°, whereas at y = 0°, having the thumb adducted and fingers slightly spread yielded higher lift values. Results show that finger and thumb positioning in swimming is a determinant of the propulsive force produced during swimming; indeed, this force is dependent on the direction of the flow over the hand and forearm, which changes across the arm’s stroke.


Author(s):  
Pedro Esteves Duarte Augusto ◽  
Marcelo Cristianini

Abstract Gate valves are the most common valve in industrial plants. However, there is no work in the literature regarding the use of computational fluid dynamics (CFD) to evaluate the fluid flow characteristics and pressure drop in gate valves. The present work evaluated the fluid flow and pressure drop through a commercial gate valve using CFD. The obtained values for the pressure loss coefficient (k) are in accordance to those described in the literature and a power type equation could be used for modeling it as function of the Reynolds Number. Fluid flow behavior through the gate valve highlighted the flow recirculation and stagnant areas, being critical for food and pharmaceutical products processing. The obtained results reinforce the advantages in using CFD as a tool for the engineering evaluation of fluid processes.


Author(s):  
Ian Torotwa ◽  
Changying Ji

In this study, turbulent flow fields in a baffled vessel stirred by counter-axial flow impeller have been investigated in comparison to the Rushton turbine. The resultant turbulence was numerically predicted using computational fluid dynamics (CFD). Turbulence models were developed in ANSYS Fluent 18.1 solver using the Navier-Stokes equation with the standard k-ε turbulence model. The Multiple Reference Frame (MRF) approach was used to simulate the impeller action in the vertical and horizontal planes of the stirred fluid volume. Velocity profiles generated from the simulations were used to predict and compare the performance of the two designs. To validate the CFD model, the simulation results were compared with experimental results from existing work and a satisfactory agreement was established. It was concluded that the counter-axial flow impeller could provide better turbulence characteristics that would improve the quality of mixing systems.


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