The Numerical Study of Oil Drop Jet from Oil-Air Lubrication Nozzle

Nozzle is an important part of oil-air lubrication system. This paper uses Computational Fluid Dynamics (CFD) software FLUENT to study the flow field of oil air, and different air pressure and nozzle throat size are discussed. The results show that: When air pressure is increased from 0.05Mpa to 0.1Mpa, the maximum diameter (2mm) percentage reduces, but the diameters distribution is almost unchanged as the air pressure is increased to 0.3MPa. The throat diameter is decreased, the mean Sauter diameter of oil drop reduces. This paper will provide a theoretical basis for oil-air lubrication nozzle design and selection.

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Numerical Study on the Extrapolation Method for Predicting the Full-scale Resistance of a Ship with an Air Lubrication System

Journal of Ocean Engineering and Technology ◽

10.26748/ksoe.2020.008 ◽

2020 ◽

Vol 34 (6) ◽

pp. 387-393

Author(s):

Dong-Young Kim ◽

Ji-Yeon Ha ◽

Kwang-Jun Paik

Keyword(s):

Numerical Study ◽

Full Scale ◽

Extrapolation Method ◽

Lubrication System ◽

Scale Resistance ◽

Air Lubrication

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Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

Metallurgical and Materials Transactions B ◽

10.1007/s11663-021-02247-x ◽

2021 ◽

Author(s):

Alexander Vakhrushev ◽

Abdellah Kharicha ◽

Ebrahim Karimi-Sibaki ◽

Menghuai Wu ◽

Andreas Ludwig ◽

...

Keyword(s):

Magnetic Field ◽

Lorentz Force ◽

Applied Magnetic Field ◽

Numerical Study ◽

Flow Direction ◽

Experimental Studies ◽

Submerged Entry Nozzle ◽

Mean Flow ◽

Slab Caster ◽

The Mean

AbstractA numerical study is presented that deals with the flow in the mold of a continuous slab caster under the influence of a DC magnetic field (electromagnetic brakes (EMBrs)). The arrangement and geometry investigated here is based on a series of previous experimental studies carried out at the mini-LIMMCAST facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The magnetic field models a ruler-type EMBr and is installed in the region of the ports of the submerged entry nozzle (SEN). The current article considers magnet field strengths up to 441 mT, corresponding to a Hartmann number of about 600, and takes the electrical conductivity of the solidified shell into account. The numerical model of the turbulent flow under the applied magnetic field is implemented using the open-source CFD package OpenFOAM®. Our numerical results reveal that a growing magnitude of the applied magnetic field may cause a reversal of the flow direction at the meniscus surface, which is related the formation of a “multiroll” flow pattern in the mold. This phenomenon can be explained as a classical magnetohydrodynamics (MHD) effect: (1) the closure of the induced electric current results not primarily in a braking Lorentz force inside the jet but in an acceleration in regions of previously weak velocities, which initiates the formation of an opposite vortex (OV) close to the mean jet; (2) this vortex develops in size at the expense of the main vortex until it reaches the meniscus surface, where it becomes clearly visible. We also show that an acceleration of the meniscus flow must be expected when the applied magnetic field is smaller than a critical value. This acceleration is due to the transfer of kinetic energy from smaller turbulent structures into the mean flow. A further increase in the EMBr intensity leads to the expected damping of the mean flow and, consequently, to a reduction in the size of the upper roll. These investigations show that the Lorentz force cannot be reduced to a simple damping effect; depending on the field strength, its action is found to be topologically complex.

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Long-Term Outcomes of Patients with Hydrocephalus Secondary to Tectal Plate Glioma versus Idiopathic Aqueductal Stenosis: Results from a Single Center

Pediatric Neurosurgery ◽

10.1159/000515516 ◽

2021 ◽

pp. 1-11

Author(s):

Hamid Reza Niknejad ◽

Melissa Frederickx ◽

Emiel Salaets ◽

Jurgen Lemiere ◽

Lieven Lagae ◽

...

Keyword(s):

Aqueductal Stenosis ◽

Maximum Diameter ◽

Benign Tumors ◽

Term Outcome ◽

Adequate Treatment ◽

Long Term Outcome ◽

Tectal Plate ◽

The Mean

Introduction: Tectal plate gliomas (TPG) constitute a distinct entity of benign tumors of the brain stem which show an indolent clinical course. Adequate treatment of secondary hydrocephalus is undoubtedly a major factor in the outcome. However, little is known about to what degree the tumor itself determines the long-term outcome of these patients. Methods: We retrospectively analyzed and compared the clinical and radiological data of 16 pediatric TPG patients with data of 12 pediatric idiopathic aqueductal stenosis (IAS) patients treated in our center from 1988 to 2018. For both groups, we assessed the long-term outcome in terms of hydrocephalus management, and for the TPG group, we assessed tumor growth during follow-up. In a separate prospective part of the study, we performed a neuropsychological evaluation in a subgroup of patients using a standardized testing battery, covering intelligence, learning, memory, executive functions, and an inventory on depression. Results: In the TPG group, the mean clinical and radiological follow-up was 84 and 70 months, respectively. On average, the maximum diameter of the tumor increased by 11% (p = 0.031) and the estimated tumor volume with 35% (p = 0.026) on radiological follow-up. The fronto-occipital horn ratio (FOHR) decreased by 23% on average after treatment. In the IAS group, the mean clinical and radiological follow-up was 117 and 85 months, respectively. In this group, the FOHR decreased by 21% on average. Neurocognitive testing revealed significant higher scores in the TPG group on global intelligence (TPG = 109, IAS = 85.5, U = 3, p < 0.01, z = −2.71), performance (TPG= 100, IAS = 85, U = 7, p = 0.03, z = −2.2), and verbal intelligence (TPG = 122, IAS = 91.5, U = 2, p < 0.00, z = −2.87) as well as working memory (TPG = 109.5, IAS = 77, U = 0.5, p = 0.01, z = −2.46). Conclusion: Our results suggest that the long-term outcome in TPG patients is acceptable and that cognition is substantially better preserved than in patients with IAS. This puts the idea of a significant contribution of the tumoral mass to disease outcome on the long term in question. Adequate and prompt management of hydrocephalus is the most important factor in long-term cognitive outcome.

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UCBO Hydraulic Oil and Application on Hydraulic Measurement for Laval Nozzle Throat Diameter

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.667.449 ◽

2015 ◽

Vol 667 ◽

pp. 449-454

Author(s):

Yang Hong ◽

Xiang Zhang ◽

Dong Xiang Shao ◽

Guang Lin Wang ◽

Li Sun

Keyword(s):

Laval Nozzle ◽

Oxidation Stability ◽

Measurement Model ◽

Diameter Measurement ◽

Liquid Pressure ◽

Nozzle Throat ◽

Hydraulic Oil ◽

Temperature Performance ◽

Measurement Principle ◽

Throat Diameter

This paper proposes a hydraulic measurement model for measuring the Laval nozzle throat diameter size. Based on measurement principle of liquid pressure – flowrate, we can get the size of Laval nozzle throat diameter by measuring the fluid flowrate through hydraulic measurement model at the fixed pressure. With good viscosity-temperature performance, low temperature performance and oxidation stability, UCBO aviation hydraulic oil is selected as the measuring medium. In the hydraulic measurement model, the diameter of the mandrel which can be regarded as gauge will directly affect the sensitivity of diameter measurement. Therefore we need to optimize the design of the mandrel of the hydraulic model.

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Load Characteristics of Steel and Concrete Tubular Members Under Jet Fire: An Experimental and Numerical Study

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 2 ◽

10.1115/omae2010-20754 ◽

2010 ◽

Author(s):

Jeong Hyo Park ◽

Bong Ju Kim ◽

Jung Kwan Seo ◽

Jae Sung Jeong ◽

Byung Keun Oh ◽

...

Keyword(s):

Cfd Simulation ◽

Numerical Study ◽

Fire Load ◽

Adiabatic Wall ◽

Fire Engineering ◽

Ansys Cfx ◽

Design Values ◽

Computational Fluid Dynamics Cfd ◽

Load Characteristics ◽

Set Up

The aim of this study was to evaluate the load characteristics of steel and concrete tubular members under jet fire, with the motivation to investigate the jet fire load characteristics in FPSO topsides. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) [1]. To obtain reliable load values, jet fire tests were carried out in parallel with a numerical study. Computational fluid dynamics (CFD) simulation was used to set up an adiabatic wall boundary condition for the jet fire to model the heat transfer mechanism. A concrete tubular member was tested under the assumption that there is no conduction effect from jet fire. A steel tubular member was tested and considered to transfer heat through conduction, convection, and radiation. The temperature distribution, or heat load, was analyzed at specific locations on each type of member. ANSYS CFX [2] and Kameleon FireEx [3] codes were used to obtain similar fire action in the numerical and experimental methods. The results of this study will provide a useful database to determine design values related to jet fire.

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A numerical study of the sedimentation of fibre suspensions

Journal of Fluid Mechanics ◽

10.1017/s0022112098002663 ◽

1998 ◽

Vol 376 ◽

pp. 149-182 ◽

Cited By ~ 70

Author(s):

MICHAEL B. MACKAPLOW ◽

ERIC S. G. SHAQFEH

Keyword(s):

Monte Carlo ◽

Steady State ◽

Monte Carlo Simulations ◽

Numerical Study ◽

Point Particle ◽

Hydrodynamic Interactions ◽

Dynamic Simulations ◽

Slender Body Theory ◽

Fibre Suspensions ◽

The Mean

The sedimentation of fibre suspensions at low Reynolds number is studied using two different, but complementary, numerical simulation methods: (1) Monte Carlo simulations, which consider interparticle hydrodynamic interactions at all orders within the slender-body theory approximation (Mackaplow & Shaqfeh 1996), and (ii) dynamic simulations, which consider point–particle interactions and are accurate for suspension concentrations of nl3=1, where n and l are the number density and characteristic half-length of the fibres, respectively. For homogeneous, isotropic suspensions, the Monte Carlo simulations show that the hindrance of the mean sedimentation speed is linear in particle concentration up to at least nl3=7. The speed is well predicted by a new dilute theory that includes the effect of two-body interactions. Our dynamic simulations of dilute suspensions, however, show that interfibre hydrodynamic interactions cause the spatial and orientational distributions to become inhomogeneous and anisotropic. Most of the fibres migrate into narrow streamers aligned in the direction of gravity. This drives a downward convective flow within the streamers which serves to increase the mean fibre sedimentation speed. A steady-state orientation distribution develops which strongly favours fibre alignment with gravity. Although the distribution reaches a steady state, individual fibres continue to rotate in a manner that can be qualitatively described as a flipping between the two orientations aligned with gravity. The simulation results are in good agreement with published experimental data.

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Negative Air Pressure on Wet Cupping in Decreasing Blood Pressures in Hypertensive Patients

Nurse Media Journal of Nursing ◽

10.14710/nmjn.v7i2.15177 ◽

2018 ◽

Vol 7 (2) ◽

pp. 116

Author(s):

Budi Darmawan ◽

Diyah Fatmasari ◽

Rr. Sri Endang Pujiast

Keyword(s):

Blood Pressure ◽

Repeated Measures ◽

Community Health Centers ◽

Intervention Group ◽

Air Pressure ◽

Control Group ◽

P Value ◽

Decrease Blood Pressure ◽

Blood Pressures ◽

The Mean

Background: Wet cupping, furthermore mentioned cupping, decreases blood pressures through the level of negative air pressures added by hydrostatics filtration pressure to reinforce the power of fluids filtration in capillaries. However, an appropriate negative air pressure to decrease blood pressure remains an uncertainty.Purpose: This study aimed to analyze negative air pressure differences on cupping in decreasing blood pressures in hypertensive patients.Methods: This is a quasi-experimental design conducted in three Community Health Centers in Langsa City, Aceh, Indonesia. The samples were 36 hypertensive males with age from 45 to 55, who were randomly stratified into two groups with cupping pressures 400 mbar (n=18) as the control group; and 540 mbar (n=18) as the intervention group. The cupping session was performed to each group on T1 (alkahil) point and in the middle line of both shoulders blade points. The systolic blood pressure (SBP) and diastolic blood pressures (DBP) were measured by validated automatic sphygmomanometer. The follow-up periods were one week and two weeks. The data were then analyzed by repeated measures ANOVA.Results: Cupping pressure of 400 mbar decreased the mean of SBP and DPB with a p-value of 0.450 and 0.026, respectively after two weeks of intervention. Meanwhile, cupping pressure of 540 mbar decreased the mean of SBP and DBP with a p-value of 0.006 and 0.057, respectively. Tests of within-subjects resulted in the p-value of 0.250 (SBP) and 0.176 (DBP) after two weeks of intervention. There were no significant differences in SBP and DBP between the intervention group and the control group.Conclusion: The cupping pressure between 400 mbar and 540 mbar could reduce blood pressure; however, the cupping pressure of 540 mbar yielded greater effect in decreasing blood pressure than the 400 mbar. Negative air vacuum pressure loads on cupping to decrease blood pressure should be considered between 400 to 540 mbar, and further studies are needed.

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Pipeline embolization device treatment of internal carotid artery terminus aneurysms

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2018-014312 ◽

2018 ◽

Vol 11 (5) ◽

pp. 485-488 ◽

Cited By ~ 5

Author(s):

Amit Pujari ◽

Brian Matthew Howard ◽

Thomas P Madaelil ◽

Susana Libhaber Skukalek ◽

Anil K Roy ◽

...

Keyword(s):

Carotid Artery ◽

Internal Carotid Artery ◽

Internal Carotid ◽

Treatment Strategies ◽

Maximum Diameter ◽

Class Iii ◽

Pipeline Embolization Device ◽

Proximal Internal Carotid Artery ◽

The Mean

BackgroundThe pipeline embolization device (PED) is approved for the treatment of large aneurysms of the proximal internal carotid artery (ICA). Its off-label application in treating aneurysms located specifically at the ICA terminus (ICA-T) has not been studied.MethodsWe conducted a retrospective chart review of patients from 2011 to 7 treated with PEDs. Out of 365 patients, 10 patients with ICA-T aneurysms were included. Patient demographics, procedural information, follow-up imaging, and clinical assessments were recorded.ResultsMean age was 46.9 years (± 8.8), and 6 (60%) patients were women. The mean maximum diameter of the aneurysms treated was 14.7 mm (± 10.7) and the mean neck diameter was 9.3 mm (± 6.6). Reasons for presentation included six incidental findings, one acute subarachnoid hemorrhage (SAH), and three patients with prior SAH. Kamran–Byrne Occlusion Scale scores for the treated aneurysms were as follows: three class IV (complete obliteration), four class III (<50% filling in both height and width for fusiform aneurysms or residual neck for saccular aneurysms), one class II fusiform aneurysm, 1 class 0 saccular aneurysm (residual aneurysm body), and one not classified due to pipeline thrombosis. Two clinically asymptomatic complications were noted: one patient who had a small distal cortical SAH post PED and one patient whose stent was found to be thrombosed on follow-up angiogram. All patients were seen in follow-up, and no patients were found to have worsening of their pre-procedure modified Rankin Scale score.ConclusionThe PED has potential for treating ICA-T aneurysms not amenable to conventional treatment strategies. Further studies are warranted to confirm the long term outcomes.

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Numerical Study on the Effect of Bend Angle on Turbulent Flow through Oscillating Bend

Chemical Product and Process Modeling ◽

10.2202/1934-2659.1436 ◽

2009 ◽

Vol 4 (1) ◽

Author(s):

Elham Ameri ◽

M Nasr Esfahany

Keyword(s):

Numerical Study ◽

Bend Angle ◽

Curvature Radius ◽

Primary Flow ◽

Mean Velocity ◽

Contour Map ◽

Curved Pipes ◽

Flow Through ◽

The Mean ◽

Turbulent Air Flow

The effect of the bend angle on the unsteady developing turbulent air flow through oscillating circular-sectioned curved pipes with the various angles of 180°, 135° and 90° was investigated numerically. The bends had a diameter of 106 mm and a curvature radius ratio of 6.0 with long, straight upstream and downstream sections. Results of the mean velocity and static pressure were obtained at a Reynolds number of 31200 and at various longitudinal stations. The velocity of the primary flow was illustrated in the form of contour map and vector diagram. From the inlet plane of the three oscillating bends to the angle of 45°, the velocity fields in 180°, 90° and 135° bends are similar. The high velocity regions, however, occur near the upper and lower parts in 90° and 180° bends, respectively.

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