A Novel Approach for the Prediction of Dynamic Features of Air Release and Absorption in Hydraulic Oils

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Junjie Zhou ◽  
Andrea Vacca ◽  
Bernhard Manhartsgruber
Keyword(s):  
Bulk Modulus ◽  
Saturation Pressure ◽  
Measurement Data ◽  
Fluid Density ◽  
Hydraulic Systems ◽  
Dynamic Features ◽  
Liquid Phases ◽  
Novel Approach ◽  
Fluid Properties ◽  
Computational Fluid Dynamics Cfd

An accurate evaluation of fluid density and bulk modulus is essential for predicting the operation of hydraulic systems and components. Among the models reported in literature to describe fluid properties, of particular success in the fluid power field are the continuous methods that assume the gas and liquid phases to be the same fluid. However, these models are typically based on steady-state equilibrium relations and, consequently, they fail in correctly predicting the dynamic features of both air release and air absorption processes. These phenomena are particularly important for machines based on open-system hydraulic circuits, in which a significant part of the system can operate with a fluid below the saturation pressure. This paper addresses this topic by proposing a novel approach suitable to describe the dynamic features of both vaporization and air release processes. The approach is based on simplified transport equations to evaluate the phase change rate and the air release/dissolve rate. These transport equation are obtained from the well-known theoretical “full cavitation model” previously developed for computational fluid dynamics (CFD). Specific tests were performed to validate particularly as concerns the air release/absorption features using a standard ISO32 mineral oil. Comparisons between model predictions and measurement data are presented for compression/decompression cycles as concerns transient fluid density and bulk modulus, and a good agreement between the two trends is found, showing the potentials of the new approach to describe typical cavitation phenomena in hydraulic systems.

How Bulk Modulus Errors Can Affect Leak Detection

1996 ◽  
Author(s):  
Henry H. Rachford ◽  
Andrew Wike
Keyword(s):  
Bulk Modulus ◽  
Measurement Data ◽  
Leak Detection ◽  
Operating Conditions ◽  
Time Data ◽  
Transient Model ◽  
Property Data ◽  
Wide Range ◽  
Fluid Properties ◽  
On Line

Liquid pipeline operators look to leak detection systems to provide continuous surveillance of their pipelines across a wide range of operating conditions; this is particularly the case for batch pipelines. Operators frequently anticipate that on-line transient modeling systems can satisfy this requirement, which they can, but have little exposure to the on-line measurement data requirements of such systems. There can be a mistaken focus on improving the quality of the real-time data normally available to facilitate pipeline operations, without due regard to providing the measurement data that the model needs. Pipeline operators are normally not concerned with a detailed characterization of fluid properties, other than in the most general sense regarding the susceptibility of adjacent fluids to mix at their interface. This paper illustrates how the lack of reliable fluid property data (specifically, bulk modulus data) can substantially impede the effectiveness of a transient model charged with the task of leak detection.

scholarly journals Distribution characteristics of reservoir fluid properties in Cuu Long basin

2019 ◽  
Vol 19 (1) ◽  
pp. 147-161
Author(s):  
Nguyen Manh Hung ◽  
Hoang Dinh Tien ◽  
Nguyen Viet Ky
Keyword(s):  
Normal Distribution ◽  
Oil And Gas ◽  
Saturation Pressure ◽  
Study Data ◽  
Distribution Characteristics ◽  
Fluid Density ◽  
Reservoir Fluid ◽  
Fluid Properties ◽  
Very High ◽  
Margin Area

Oil and gas have been discovered and produced from Cuu Long basin for more than 20 years however the distribution charateristics according to stratigraphy have not been studied. In this study, data from more than 200 PVT reports of more than 30 discoveries and published reports of previous studies were investigated to find out the distribution characteristics of reservoir fluid properties. The results show that oil and gas in Cuu Long basin mainly follow normal distribution, in some areas they are in redistribution (retrogradation) stage. Saturation pressure, GOR and compressibility are very high at the centre area and rapidly reduce at the margin area, whereas reservoir fluid density is in the inverse trend. Oil and gas have tendency to accumulate in NW-SE direction. Condensate discoveries in Cuu Long basin mainly result from redistribution process except some discoveries in center of basin.

scholarly journals Application of Deep Reinforcement Learning to Predict Shaft Deformation Considering Hull Deformation of Medium-Sized Oil/Chemical Tanker

2021 ◽  
Vol 9 (7) ◽  
pp. 767
Author(s):  
Shin-Pyo Choi ◽  
Jae-Ung Lee ◽  
Jun-Bum Park
Keyword(s):  
Reinforcement Learning ◽  
Reaction Force ◽  
Measurement Data ◽  
System Stability ◽  
Main Bearing ◽  
Shaft System ◽  
Novel Approach ◽  
Design Changes ◽  
Prediction Techniques ◽  
Shaft Deformation

The enlargement of ships has increased the relative hull deformation owing to draft changes. Moreover, design changes such as an increased propeller diameter and pitch changes have occurred to compensate for the reduction in the engine revolution and consequent ship speed. In terms of propulsion shaft alignment, as the load of the stern tube support bearing increases, an uneven load distribution occurs between the shaft support bearings, leading to stern accidents. To prevent such accidents and to ensure shaft system stability, a shaft system design technique is required in which the shaft deformation resulting from the hull deformation is considered. Based on the measurement data of a medium-sized oil/chemical tanker, this study presents a novel approach to predicting the shaft deformation following stern hull deformation through inverse analysis using deep reinforcement learning, as opposed to traditional prediction techniques. The main bearing reaction force, which was difficult to reflect in previous studies, was predicted with high accuracy by comparing it with the measured value, and reasonable shaft deformation could be derived according to the hull deformation. The deep reinforcement learning technique in this study is expected to be expandable for predicting the dynamic behavior of the shaft of an operating vessel.

Effect of Dilution on Acoustic and Transport Properties of Reservoir Fluid Systems and Their Interplay

SPE Journal ◽  
2020 ◽  
Vol 25 (06) ◽  
pp. 2867-2880
Author(s):  
Ram R. Ratnakar ◽  
Edward J. Lewis ◽  
Birol Dindoruk
Keyword(s):  
Measurement Techniques ◽  
Saturation Pressure ◽  
Ultrasonic Pulse ◽  
Acoustic Velocity ◽  
Viscosity Data ◽  
Reservoir Fluid ◽  
Fluid Systems ◽  
Fluid Properties ◽  
Volume Measurements ◽  
Live Oil

Summary Acoustic velocity is one of the key thermodynamic properties that can supplement phase behavior or pressure/volume/temperature (PVT) measurements of pure substances and mixtures. Several important fluid properties are relatively difficult to obtain through traditional measurement techniques, correlations, or equation of state (EOS) models. Acoustic measurements offer a simpler method to obtain some of these properties. In this work, we used an experimental method based on ultrasonic pulse-echo measurements in a high-pressure/high-temperature (HP/HT) cell to estimate acoustic velocity in fluid mixtures. We used this technique to estimate related key PVT parameters (such as compressibility), thereby bridging gaps in essential data. In particular, the effect of dilution with methane (CH4) and carbon dioxide (CO2) at pressures from 15 to 62 MPa and temperatures from 313 to 344 K is studied for two reservoir fluid systems to capture the effect of the gas/oil ratio (GOR) and density variations on measured viscosity and acoustic velocity. Correlative analysis of the acoustic velocity and viscosity data were then performed to develop an empirical correlation that is a function of GOR. Such a correlation can be useful for improving the interpretation of the sonic velocity response and the calibration of viscosity changes when areal fluid properties vary with GOR, especially in disequilibrium systems. In addition, under isothermal conditions, the acoustic velocity of a live oil decreases monotonically with decreasing pressure until the saturation point where the trend is reversed. This observation can also be used as a technique to estimate the saturation pressure of a live oil or as a byproduct of the target experiments. It supplements the classical pressure/volume measurements to determine the bubblepoint pressure.

scholarly journals Return Flight

1999 ◽  
Vol 121 (12) ◽  
pp. 62-64 ◽  
Author(s):  
Peggy Chalmers
Keyword(s):  
Flight Control ◽  
High Performance ◽  
Development Work ◽  
Flight Control System ◽  
Complex Interactions ◽  
System A ◽  
Physical Testing ◽  
Fluid Properties ◽  
Computational Fluid Dynamics Cfd ◽  
Thrust Control

This article focuses on the fact that using computational fluid dynamics (CFD) and design of experiments (DOE) software, researchers are in pursuit of aircraft fluidics thrust control without moving component parts. Fluidics’ performance is dictated by complex interactions among approximately two dozen geometric and fluid properties. These complex interactions probably proved overwhelming to early researchers seeking a stable, reliable rocket flight control system. A major advantage of DOE is that it allows all the parameters to vary simultaneously. A single permutation, on the other hand, varies one parameter at a time and cannot deal with interactions among the fixed parameters. There is still more development work to be done, but indications are that CFD and DOE are leading Lockheed Martin to a promising design. Physical testing reinforces the belief that a fluidic nozzle can achieve the performance levels required. The technology that never got off the ground in the early rocket era may find itself flying high in the next generation of high-performance tactical aircraft.

Application of CFD in Designing Spacers: A Novel Approach

2000 ◽  
Author(s):  
Vahid Jalili ◽  
Mayur K. Patel ◽  
Christopher Bailey
Keyword(s):  
Experimental Data ◽  
Optimum Size ◽  
Large Area ◽  
Optimum Time ◽  
Actual Length ◽  
Inlet Velocity ◽  
Biomedical Device ◽  
Novel Approach ◽  
Computational Fluid Dynamics Cfd ◽  
Inlet Boundary Condition

Abstract The aim of this paper is to report on a novel approach used in designing spacer (a biomedical device used to aid inhalation of the drug). The Computational Fluid Dynamics (CFD) technique has been around for some years, but to date has not been used in designing spacers. In the present study the commercial CFD engines used were FLUENT-5.1.1 and PHOENICS. The study covered a large area taking into account various parameter changes such as the inlet boundary condition i.e. changing the velocity at inlet, varying the jet angle at entry to the spacer and the actual length of the spacer. The results were possible were compared to the experimental data available and generally the comparison was good. The findings from this research have highlighted, that there is an optimum size of 6cm and inlet velocity of 30m/s which result in an increased efficiency. It was also found that there is an optimum time of 0.4 sec. For which the highest drug concentration appears to be present.

scholarly journals High Order Volumetric Directional Pattern for Video-Based Face Recognition

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Almabrok Essa ◽  
Vijayan Asari
Keyword(s):  
State Of The Art ◽  
Directional Pattern ◽  
High Order ◽  
Dynamic Textures ◽  
Dynamic Features ◽  
Novel Approach ◽  
Variation Patterns ◽  
Directional Variation ◽  
Video Based Face Recognition ◽  
Information Dynamic

Describing the dynamic textures has attracted growing attention in the field of computer vision and pattern recognition. In this paper, a novel approach for recognizing dynamic textures, namely, high order volumetric directional pattern (HOVDP), is proposed. It is an extension of the volumetric directional pattern (VDP) which extracts and fuses the temporal information (dynamic features) from three consecutive frames. HOVDP combines the movement and appearance features together considering the nth order volumetric directional variation patterns of all neighboring pixels from three consecutive frames. In experiments with two challenging video face databases, YouTube Celebrities and Honda/UCSD, HOVDP clearly outperformed a set of state-of-the-art approaches.

scholarly journals Multiphase Flow Effects in a Horizontal Oil and Gas Separator

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2116 ◽  
Author(s):  
Michael Frank ◽  
Robin Kamenicky ◽  
Dimitris Drikakis ◽  
Lee Thomas ◽  
Hans Ledin ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Petroleum Industry ◽  
Oil And Gas Industry ◽  
Fluid Mixture ◽  
Gas Industry ◽  
Liquid Phases ◽  
Industry Applications ◽  
Computational Fluid Dynamics Cfd ◽  
Gas Separator ◽  
Flow Effects

An oil and gas separator is a device used in the petroleum industry to separate a fluid mixture into its gaseous and liquid phases. A computational fluid dynamics (CFD) study aiming to identify key design features for optimising the performance of the device, is presented. A multiphase turbulent model is employed to simulate the flow through the separator and identify flow patterns that can impinge on or improve its performance. To verify our assumptions, we consider three different geometries. Recommendations for the design of more cost- and energy-effective separators, are provided. The results are also relevant to broader oil and gas industry applications, as well as applications involving stratified flows through channels.

Scaling of the Hydroelastic Response of Flexible Lifting Bodies in Transitional and Turbulent Flows

2013 ◽  
Author(s):  
Antoine Ducoin ◽  
Yin Lu Young
Keyword(s):  
Turbulent Flows ◽  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Full Scale ◽  
Stress Distributions ◽  
Viscous Effects ◽  
Scaling Methods ◽  
Fluid Properties ◽  
Computational Fluid Dynamics Cfd ◽  
Hydroelastic Response

The objective of this research is to derive and validate scaling relationships for flexible lifting bodies in transitional and turbulent flows. The motivation is to help the design and interpretation of reduced-scale experimental studies of flexible hydrofoils, with focus on the influence of viscous effects on the hydroelastic response. The numerical method is based on a previous validated viscous FSI solver presented in [1]. It is based on the coupling between a commercial Computational Fluid Dynamics (CFD) solver, CFX, and a simple two-degrees-of-freedom (2-DOF) system that simulates the free tip section displacement of a cantilevered, rectangular hydrofoil. To validate the scaling relations, sample numerical results are shown for three geometrically similar models: full scale, 1/2 scale and 1/10 scale. On the fluid side, although the effects of gravity and compressibility are assumed to be negligible, three different methods of scaling the velocity are considered: Reynolds scaling, Froude scaling, and Mach scaling. The three scaling methods produce different velocity scales when the fluid properties and gravitational constant are the same between the model and prototype, which will lead to different scaling for the material properties. The results suggest that by applying Mach scaling (which does not mean the flow is compressible, but simply requires the relative inflow velocity and fluid properties to be the same between the model and the prototype) and Re ≥ 2 × 106, the same material as the full scale could be used, which will lead to similar stress distributions, in addition to similar strains, and hence similar hydroelastic response and failure mechanisms. However, if Re ≤ 2 × 106 and Mach scale is used, a viscous correction is required to properly extrapolate the experimental results to full-scale.

Ink Jet Deposition of Ceramic Suspensions: Modeling and Experiments of Droplet Formation

2000 ◽  
Vol 624 ◽  
Author(s):  
N. Reis ◽  
B. Derby
Keyword(s):  
Driving Voltage ◽  
Concentrated Suspensions ◽  
Cfd Modelling ◽  
Particulate Suspensions ◽  
Ink Jet ◽  
Fluid Properties ◽  
Printing System ◽  
Modeling And Experiments ◽  
Computational Fluid Dynamics Cfd ◽  
Ceramic Suspensions

ABSTRACTWe have successfully printed green ceramic objects from slurries of Al2O3 dispersed in paraffin wax using a commercial ink-jet printer developed for pattern making (Sanders Prototype MM6PRO). Concentrated suspensions are generally more viscous than the fluids normally passed through ink jet heads. This may alter the response of the printing system to its process parameters, e.g. driving voltage and frequency. We have explored the influence of fluid properties on the ink jet behaviour using Computational Fluid Dynamics (CFD) modelling and a parallel experimental study to determine the optimum printing conditions for particulate suspensions.

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