Estimations of leakages through gaps at ‘transition’ contacts using computational fluid dynamics and photoimaging of core-flow cavitation features in Gerotor pumps

2021 ◽  
pp. 095440892110336
Author(s):  
Debanshu Roy ◽  
Rathindranath Maiti ◽  
Prasanta K Das ◽  
Piotr Antoniak ◽  
Jaroslaw Stryczek
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Fluid Pressure ◽  
Flow Characteristics ◽  
Flow Process ◽  
Short Period ◽  
Gerotor Pump ◽  
Gerotor Pumps ◽  
Good Agreement

Chambers in the Gerotor pump units are separated by metal-to-metal geometrically form-closed higher pair active contacts in the lobes of star and ring components. With rotation when the chamber volumes expand and contract, the active contacts move on lobe profiles and are subjected to deformations due to contact stress caused by fluid pressure and transmitted torque. Evidently at two transition active contacts, which separate the high-pressure chambers from the low-pressure chambers, gaps are generated due to contact deformations. However, it is for a short period of time during operation and mostly not at the same time in the two transition contacts. From our experimental visual investigation by photoimaging technique on flow processes, we have visualized that at some angular positions of the star–ring, cavitation occurs inside the chamber. In an earlier work, in the estimation of gaps in transition contacts, we have first evaluated the stresses, deformations at all ideally form-closed active contacts in our chosen Gerotor pump using static structural analysis in the Ansys® environment. In the present work, to investigate the flow characteristics, including the formation of cavitations in the Gerotor pump, numerical analysis using the computational fluid dynamics tool in the Ansys® environment has been carried out. We analyze the flow process for the different angular positions of a star. Results obtained by the numerical analysis have good agreement with the flow patterns visualized experimentally.

scholarly journals STUDI ALIRAN AIR PADA BALL VALVE DAN BUTTERFLY VALVE MENGGUNAKAN METODE SIMULASI COMPUTATIONAL FLUID DYNAMICS

2019 ◽  
Vol 4 (1) ◽  
pp. 38-49
Author(s):  
Rizky Arman ◽  
Yovial Mahyoedin ◽  
Kaidir Kaidir ◽  
Nando Desilpa
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Water Distribution ◽  
Fluid Pressure ◽  
Flow Simulation ◽  
Ball Valve ◽  
Material Strength ◽  
Butterfly Valve ◽  
Mechanical Devices ◽  
Ss 304

ABSTRAKValve adalah alat mekanis yang mengatur aliran atau tekanan cairan. Fungsinya adalah  menutup atau membuka aliran, mengontrol laju aliran, mengalihkan aliran, mencegah aliran balik, mengontrol tekanan, atau mengurangi tekanan. Masalah yang umumnya ditemui adalah  penutupan valve tidak sempurna dikarenakan adanya kotoran-kotoran yang menghalangi penutupnya untuk menutup secara sempurna. Penanganannya yang paling sederhana yaitu membersihkan dudukan dari kotoran-kotoran tadi secara intensif dan dilakukan pelumasan. Penelitian ini bertujuan untuk menjelaskan gambaran tentang simulasi aliran pada ball valve dan butterfly valve. Dan menjelaskan perbandingan tekanan, temperatur dan kecepatan distribusi air pada dua jenis valve. Tekanan fluida pada kondisi tertutup berbeda dengan kondisi terbuka. Hal ini akan berdampak terhadap kekuatan ball valve dan butterfly valve. Tekanan yang besar atau melebihi spesifikasi akan mempengaruhi mekanisme kerja dan kekuatan material. Pengaruh tekanan ini menjadi sangat penting dalam ball valve dan butterfly valve karena tekanan fluida dengan temperatur, pada  kondisi tertentu bisa di luar batas spesifikasi khususnya pada ball valve Sanitary SS316 Mounting Pad 3 inci dan butterfly valve Sanitary SS 304 3 inci. Metode yang digunakan adalah Computational Fluid Dynamics dengan bantuan Software Flow Simulasi Solidwork 2014.Kata Kunci: Ball and Butterfly Valve, Solidwork, Flow Simulasi, CFD, Tekanan, Temperatur, Kecepatan aliran. ABSTRACTValves are mechanical devices that regulate fluid flow or pressure. Its function can close or open the flow, control the flow rate, divert flow, prevent backflow, control pressure, or reduce pressure. The problem commonly encountered is that the valve closure is not perfect due to the impurities that prevent the cover from closing completely. The simplest handling is to clean the holder from the dirts earlier and do lubrication. This study aims to explain the description of the flow simulation on ball valve and butterfly valve. This study also explain the comparison of pressure, temperature and velocity of water distribution in two types of valve heads. Fluid pressure under closed conditions is different from opening conditions. This will affect the strength of the ball valve and butterfly valve as a valve. Pressure that is large or exceeds specifications will affect the working mechanism and material strength. The effect of this pressure becomes very important in the ball valve and butterfly valve because of  fluid pressure with temperature under certain conditions it can be out of the specification limits, especially in Sanitary SS316 Mounting Pad 3-inch ball valve and SS 304 3 inch Sanitary butterfly valve. This method was used in research is Computational Fluid Dynamics by utilizing of Flow Simulation Solidwork 2014 Software.Keywords: Ball Valve, Butterfly Valve, Solidwork 2014, Flow Simulation, CFD, Pressure, Temperature, Velocity

Numerical Analysis of the LCS 2 airwake to understand potential interactions during helipcopter operations

2015 ◽  
Author(s):  
Brent S. Paul
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Flow Field ◽  
Ship Design ◽  
It Impacts ◽  
Flight Envelope ◽  
Computational Fluid Dynamics Cfd ◽  
Potential Interactions ◽  
Flight Deck

The successful integration of aviation capabilities aboard ships is a complex endeavor that must balance ship design with the flight envelope of the helicopter. This can be particularly important when considering air wakes and other flow around the superstructure as it impacts the flight deck. This flow can generate unsteady structures that may interfere with safe helicopter operations. Computational fluid dynamics (CFD) is commonly used to characterize the flow field and assess potential impacts to the flight envelope, which can be used to help define an operating envelope for helicopter operations.

Numerical Simulation of the Gear Flowmeter Reveal Based on Pumplinx

2014 ◽  
Vol 687-691 ◽  
pp. 679-683 ◽  
Author(s):  
Jun Zhang ◽  
Yong Wu ◽  
Hong Mei Tang ◽  
Chun Ren Tang ◽  
Xian Hua Li
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Oil Spill ◽  
Practical Work ◽  
Measuring Accuracy ◽  
Internal Gear

The oil spill will directly affect the measuring accuracy of the gear flowmeter, so use the computational fluid dynamics software to calculate the leakage regulation of the internal gear flowmeter is one of the important things. Based on Pumplinx, when the end clearances of the gear flowmeter were 0um, 10um, 20um, 30um, 40um and 50um, the corresponding numerical analysis of spillage was carried out. From the results of numerical analysis, with the increase of the end clearance, the leakage amplification will also increase. In practical work, we should control the end clearance of gear flowmeter strictly while the gear works normally.

Review of Computational Fluid Dynamics Studies on Chemical Looping Combustion

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Yali Shao ◽  
Ramesh K. Agarwal ◽  
Xudong Wang ◽  
Baosheng Jin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Flow Process ◽  
Gas Leakage ◽  
Fuel Reactor ◽  
Energy Penalty

Abstract Chemical looping combustion (CLC) is an attractive technology to achieve inherent CO2 separation with low energy penalty. In CLC, the conventional one-step combustion process is replaced by two successive reactions in two reactors, a fuel reactor (FR) and an air reactor (AR). In addition to experimental techniques, computational fluid dynamics (CFD) is a powerful tool to simulate the flow and reaction characteristics in a CLC system. This review attempts to analyze and summarize the CFD simulations of CLC process. Various numerical approaches for prediction of CLC flow process are first introduced and compared. The simulations of CLC are presented for different types of reactors and fuels, and some key characteristics including flow regimes, combustion process, and gas-solid distributions are described in detail. The full-loop CLC simulations are then presented to reveal the coupling mechanisms of reactors in the whole system such as the gas leakage, solid circulation, redox reactions of the oxygen carrier, fuel conversion, etc. Examples of partial-loop CLC simulation are finally introduced to give a summary of different ways to simplify a CLC system by using appropriate boundary conditions.

CFD Comparison of Clearance Flow in a Rotor-Casing Assembly Using Asymmetric vs. Symmetric Lobe Rotors

2003 ◽  
Author(s):  
Bassam Abu-Hijleh ◽  
Jiyuan Tu ◽  
Aleksander Subic ◽  
Huafeng Li ◽  
Katherine Ilie
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Mesh Generation ◽  
Cfd Analysis ◽  
Air Leakage ◽  
Flow Conditions ◽  
Leakage Path ◽  
Clearance Flow ◽  
Computational Fluid Dynamics Cfd

The performance of a Rotor-Casing Assembly is influenced more by the internal air leakages than by any other thermo-fluid aspect of its behaviour. The pressure difference driving the air along a leakage path varies periodically and does so in a manner that may not be the same for every leakage path. So the distribution of leakage through the various leakage paths within the machine is important for the improvement of its performance. The total volume of air leakage and the distribution of the leakage among the different paths depend on the rotor-rotor and rotor-casing clearances as well as the geometry of the rotors’ lobes. Computational Fluid Dynamics (CFD) analysis was carried out using the FLUENT. Geometry definition, mesh generation, boundary and flow conditions, and solver parameters have all been investigated as the part of the numerical analysis. This analysis was conducted for static rotors at different positions. The results indicate that the size of the clearances as well as the geometry of the rotors’ lobes can have a significant effect on the total volume of the air leakage as well as the distribution of the leakage among the three main leakage paths. The results can be used to ascertain the proper levels of clearances to be used and the best rotor lobes geometry to be used for the practical reduction of air leakage.

scholarly journals Analysis of a Converging, Annular, Isothermal Melt Blowing Jet Using Computational Fluid Dynamics

2005 ◽  
Vol os-14 (3) ◽  
pp. 1558925005os-14
Author(s):  
Eric M. Moore ◽  
Dimitrios V. Papavassiliou ◽  
Robert L. Shambaugh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Near Field ◽  
Flow Characteristics ◽  
Sectional Area ◽  
Melt Blowing ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Computational Fluid Dynamics Cfd

An unconventional melt blowing die was analyzed using computational fluid dynamics (CFD). This die has an annular configuration wherein the jet inlet is tapered (the cross-sectional area decreases) as the air approaches the die face. It was found that the flow characteristics of this die are different from conventional slot and annular dies. In particular, for the tapered die the near-field normalized turbulent kinetic energy was found to be lower at shallow die angles. Also, it was found that the peak mean velocity behavior was intermediate between that of conventional annular and slot dies. The centerline turbulence profiles were found to be qualitatively similar to those of annular dies; quantitatively, higher values were present for tapered dies.

scholarly journals Numerical analysis of the liquid ejection due to the gaseous jet impact through computational fluid dynamics

2018 ◽  
Vol 71 (1) ◽  
pp. 53-57 ◽  
Author(s):  
Hiuller Castro Araújo ◽  
Eliana Ferreira Rodrigues ◽  
Elisangela Martins Leal
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Jet Impact

Computed tomography angiography as an adjunct to computational fluid dynamics for prediction of oxygenator thrombus formation

Perfusion ◽  
2020 ◽  
pp. 026765912094410
Author(s):  
Robert G Conway ◽  
Jiafeng Zhang ◽  
Jean Jeudy ◽  
Charles Evans ◽  
Tieluo Li ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computed Tomography ◽  
Computational Fluid Dynamics ◽  
Computed Tomography Angiography ◽  
Thrombus Formation ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Region Of Interest ◽  
Computational Fluid Dynamics Analysis ◽  
Clot Burden

Introduction: Extracorporeal membrane oxygenation circuit performance can be compromised by oxygenator thrombosis. Stagnant blood flow in the oxygenator can increase the risk of thrombus formation. To minimize thrombogenic potential, computational fluid dynamics is frequently applied for identification of stagnant flow conditions. We investigate the use of computed tomography angiography to identify flow patterns associated with thrombus formation. Methods: A computed tomography angiography was performed on a Quadrox D oxygenator, and video densitometric parameters associated with flow stagnation were measured from the acquired videos. Computational fluid dynamics analysis of the same oxygenator was performed to establish computational fluid dynamics–based flow characteristics. Forty-one Quadrox D oxygenators were sectioned following completion of clinical use. Section images were analyzed with software to determine oxygenator clot burden. Linear regression was used to correlate clot burden to computed tomography angiography and computational fluid dynamics–based flow characteristics. Results: Clot burden from the explanted oxygenators demonstrated a well-defined pattern, with the largest clot burden at the corner opposite the blood inlet and outlet. The regression model predicted clot burden by region of interest as a function of time to first opacification on computed tomography angiography (R2 = 0.55). The explanted oxygenator clot burden map agreed well with the computed tomography angiography predicted clot burden map. The computational fluid dynamics parameter of residence time, when summed in the Z-direction, was partially predictive of clot burden (R2 = 0.35). Conclusion: In the studied oxygenator, clot burden follows a pattern consistent with clinical observations. Computed tomography angiography–based flow analysis provides a useful adjunct to computational fluid dynamics–based flow analysis in understanding oxygenator thrombus formation.

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