Interferometric Deformation Measurement of Elastohydrodynamically Loaded Surfaces

1978 ◽  
Vol 100 (4) ◽  
pp. 508-509 ◽  
Author(s):  
J. Jakobsen ◽  
P. C. Larsen
Keyword(s):  
Contact Area ◽  
Operating Conditions ◽  
Deformation Measurement ◽  
Optical Interference ◽  
Actual Operating ◽  
Pressure Profiles ◽  
Line Contacts ◽  
High Degree ◽  
Sufficient Precision

A method of determining deformations of elastohydrodynamic point and line contacts under actual operating conditions is presented. An optical interference of two beams is applied. The method appears to give a high degree of accuracy and thereby offers the possibility of determining pressure profiles over the contact area with sufficient precision for viscometric purposes.

The behaviour of heavily loaded line contacts with transverse roughness

1999 ◽  
Vol 213 (4) ◽  
pp. 309-320 ◽  
Author(s):  
C. J. Hooke
Keyword(s):  
Surface Roughness ◽  
Full Range ◽  
Numerical Results ◽  
Operating Conditions ◽  
Entrainment Velocity ◽  
Original Surface ◽  
Line Contacts ◽  
Transverse Roughness ◽  
Inlet Length

In heavily loaded, piezoviscous contacts the surface roughness tends to be flattened inside the conjunction by any relative sliding of the surfaces. However, before it is flattened, the roughness affects the inlet to the contact, producing clearance variations there. These variations are then convected through the contact, at the entrainment velocity, producing a clearance distribution that differs from the original surface. The present paper explores this behaviour and establishes how the amplitude of the convected clearance varies with wavelength and operating conditions. It is shown that the primary influence is the ratio of the wavelength to the inlet length of the conjunction. Where this ratio is large, the roughness is smoothed and there is little variation in clearance under the conjunction. Where the ratio is small, significant variations in clearance may occur but the precise amplitude and phasing depend on the ratio of slide to roll velocities and on the value of a piezoviscous parameter, c. The numerical results agree closely with existing solutions but extend these to cover the full range of operating conditions.

THE VALUE OF FINE BUBBLE DIFFUSER TESTING UNDER ACTUAL OPERATING CONDITIONS IN A HIGHLY INDUSTRIAL WASTEWATER

2005 ◽  
Vol 2005 (14) ◽  
pp. 2232-2247
Author(s):  
Michael S. Demko ◽  
Frank Coughenour ◽  
John J. Pacifici ◽  
Sam Jeyanayagam ◽  
David T. Redmon
Keyword(s):  
Industrial Wastewater ◽  
Operating Conditions ◽  
Actual Operating ◽  
Fine Bubble

Use of Horizontal Drift-Flux Models For Simulating Wellbore Flow in SAGD Operations

2021 ◽  
Author(s):  
Mohammad Heidari ◽  
Christopher Istchenko ◽  
William Bailey ◽  
Terry Stone
Keyword(s):  
Flux Flow ◽  
Pressure Drops ◽  
Steam Assisted Gravity Drainage ◽  
Drift Flux ◽  
Pressure Profiles ◽  
Well Model ◽  
Inclination Angles ◽  
Operation Pressure ◽  
Reservoir Simulator ◽  
High Degree

Abstract The paper examines new horizontal drift-flux correlations for their ability to accurately model phase flow rates and pressure drops in horizontal and undulating wells that are part of a Steam-Assisted Gravity Drainage (SAGD) field operation. Pressure profiles within each well correlate to the overall performance of the pair. SAGD is a low-pressure process that is sensitive to reservoir heterogeneity and other factors, hence accurate simulation of in situ wellbore pressures is critical for both mitigating uneven steam chamber evolution and optimizing wellbore design and operation. Recently published horizontal drift-flux correlations have been implemented in a commercial thermal reservoir simulator with a multi-segment well model. Valid for horizontally drilled wells with undulations, they complement previously reported drift-flux models developed for vertical and inclined wells down to approximately 5 degrees from horizontal. The formulation of these correlations has a high degree of nonlinearity. These models are tested in simulations of SAGD field operations. First, an overview of drift-flux models is discussed. This differentiates those based on vertical flow with gravity segregation to those that model horizontal flow with stratified and slug flow regimes. Second, the most recent and significant drift-flux correlation by Bailey et al. (2018, and hereafter referred to as Bailey-Tang-Stone) was robustly designed to be used in the well model of a reservoir simulator, can handle all inclination angles and was optimized to experimental data from the largest available databases to date. This and earlier drift-flux models are reviewed as to their strengths and weaknesses. Third, governing equations and implementation details are given of the Bailey-Tang-Stone model. Fourth, six case studies are presented that illustrate homogeneous and drift-flux flow model differences for various well scenarios.

The Impact of Electric Hybrid Compressor to Make Transport Environmentally Friendly

2013 ◽  
Vol 391 ◽  
pp. 207-212
Author(s):  
Maciej Bajerlein
Keyword(s):  
Energy Consumption ◽  
Operating Conditions ◽  
Vehicle Speed ◽  
Suspension Systems ◽  
Actual Operating ◽  
Vehicle Operation ◽  
Total Energy Balance ◽  
The Impact ◽  
Road Emission ◽  
Speed Engine

This paper presents the investigations, whose aim was to determine the influence of the operation of electric and mechanical compressors on the energy consumption of city buses in public transport. The tests were performed on pneumatic systems used in city transit vehicles whose underlying component is a compressor generating pressure for the brake and suspension systems. Owing to the application of a portable analyzer - SEMTECH DS the emissions (with a secondly resolution) of CO, HC, NOx, CO2 in the exhaust gases were measured. The on-road emission tests were performed in the actual operating conditions in SORT driving tests. These tests reflect the actual vehicle operation in a real task through preset procedures of their realization and measurements determining the energy consumption and exhaust emissions or the influence of the vehicle accessories and all variables (vehicle speed, engine load, acceleration or distance covered) on the total energy balance. The on-road tests were performed on a runway of the Bednary airstrip in Poland.

Ambient Condition Effects on NOx and CO Emissions From Process Heaters

2008 ◽  
Author(s):  
Wesley R. Bussman ◽  
Charles E. Baukal
Keyword(s):  
Atmospheric Pressure ◽  
Ambient Air ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Ambient Conditions ◽  
Fuel Gas ◽  
Natural Draft ◽  
Actual Operating ◽  
Wide Range ◽  
Pollution Emissions

Because process heaters are typically located outside, their operation is subject to the weather. Heaters are typically tuned at a given set of conditions; however, the actual operating conditions may vary dramatically from season to season and sometimes even within a given day. Wind, ambient air temperature, ambient air humidity, and atmospheric pressure can all significantly impact the O2 level, which impacts both the thermal efficiency and the pollution emissions from a process heater. Unfortunately, most natural draft process burners are manually controlled on an infrequent basis. This paper shows how changing ambient conditions can considerably impact both CO and NOx emissions if proper adjustments are not made as the ambient conditions change. Data will be presented for a wide range of operating conditions to show how much the CO and NOx emissions can be affected by changes in the ambient conditions for fuel gas fired natural draft process heaters, which are the most common type used in the hydrocarbon and petrochemical industries. Some type of automated burner control, which is virtually non-existent today in this application, is recommended to adjust for the variations in ambient conditions.

Investigation of Squeeze Film Damper Forces Produced by Circular Centered Orbits

1978 ◽  
Vol 100 (1) ◽  
pp. 15-21 ◽  
Author(s):  
E. Feder ◽  
P. N. Bansal ◽  
A. Blanco
Keyword(s):  
Aircraft Engine ◽  
Analytical Investigation ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Oil Viscosity ◽  
Pressure Transducers ◽  
Pressure Distributions ◽  
Pressure Profiles ◽  
Force Components ◽  
Type Pressure

This paper presents the results of an experimental and analytical investigation of the dynamic forces generated by a squeeze film bearing damper constrained to move in circular centered orbits. These orbits were mechanically produced in a specially designed, end sealed, test rig. Aircraft engine damper geometry and operating conditions were simulated. The effect of journal speed, oil viscosity, inlet pressure, and eccentricity ratio on the damper performance was studied. The pressure distributions about the journal were measured for each test condition by high-response diaphragm-type pressure transducers. These pressure profiles were numerically integrated to determine the force components of the squeeze film. Experimental results were compared to an analysis which is summarized in this paper and included the effects of inlet and cavitation pressures. The “long bearing theory” was found to be reasonably accurate in predicting the shape and magnitude of the pressure distribution. Considerable emphasis was directed to the study of the circumferential pressure distributions between 180 deg and 360 deg since aircraft engine dampers generally operate in this region. For the cavitated film (i.e., pressure distributions less than 360 deg), accurate prediction of the damper forces was found to be critically dependent on the effect of inlet and cavitation pressures.

Traction in EHL Line Contacts Using Free-Volume Pressure-Viscosity Relationship With Thermal and Shear-Thinning Effects

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Punit Kumar ◽  
M. M. Khonsari
Keyword(s):  
Free Volume ◽  
Elastohydrodynamic Lubrication ◽  
Approximate Equation ◽  
Shear Thinning ◽  
Operating Conditions ◽  
Limiting Shear Stress ◽  
Line Contacts ◽  
Traction Coefficient ◽  
Simulation Results ◽  
Volume Equation

This paper investigates the traction behavior in heavily loaded thermo-elastohydrodynamic lubrication (EHL) line contacts using the Doolittle free-volume equation, which closely represents the experimental viscosity-pressure-temperature relationship and has recently gained attention in the field of EHL, along with Tait’s equation of state for compressibility. The well-established Carreau viscosity model has been used to describe the simple shear-thinning encountered in EHL. The simulation results have been used to develop an approximate equation for traction coefficient as a function of operating conditions and material properties. This equation successfully captures the decreasing trend with increasing slide to roll ratio caused by the thermal effect. The traction-slip characteristics are expected to be influenced by the limiting shear stress and pressure dependence of lubricant thermal conductivity, which need to be incorporated in the future.

scholarly journals Numerical Modeling of Foam Drilling Hydraulics

2007 ◽  
Vol 4 (1) ◽  
pp. 103 ◽  
Author(s):  
Ozcan Baris ◽  
Luis Ayala ◽  
W. Watson Robert
Keyword(s):  
Drilling Fluid ◽  
Operating Conditions ◽  
Drilling Fluids ◽  
Drilling Mud ◽  
Lost Circulation ◽  
Pressure Profiles ◽  
Drilling Operations ◽  
Parametric Studies ◽  
Bit Life ◽  
Foam Drilling

The use of foam as a drilling fluid was developed to meet a special set of conditions under which other common drilling fluids had failed. Foam drilling is defined as the process of making boreholes by utilizing foam as the circulating fluid. When compared with conventional drilling, underbalanced or foam drilling has several advantages. These advantages include: avoidance of lost circulation problems, minimizing damage to pay zones, higher penetration rates and bit life. Foams are usually characterized by the quality, the ratio of the volume of gas, and the total foam volume. Obtaining dependable pressure profiles for aerated (gasified) fluids and foam is more difficult than for single phase fluids, since in the former ones the drilling mud contains a gas phase that is entrained within the fluid system. The primary goal of this study is to expand the knowledge-base of the hydrodynamic phenomena that occur in a foam drilling operation. In order to gain a better understanding of foam drilling operations, a hydrodynamic model is developed and run at different operating conditions. For this purpose, the flow of foam through the drilling system is modeled by invoking the basic principles of continuum mechanics and thermodynamics. The model was designed to allow gas and liquid flow at desired volumetric flow rates through the drillstring and annulus. Parametric studies are conducted in order to identify the most influential variables in the hydrodynamic modeling of foam flow. 

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