scholarly journals Modeling Studies of Multiphase Fluid and Heat Flow Processes in Nuclear Waste Isolation

1988 ◽  
Vol 127 ◽  
Author(s):  
Karsten Pruess
Keyword(s):  
Heat Flow ◽  
Unsaturated Zone ◽  
Waste Package ◽  
Flow Problems ◽  
Saturated Formations ◽  
Flow Effects ◽  
And Performance ◽  
Multiphase Fluid ◽  
Water Saturated ◽  
Physical Phenomena

ABSTRACTMultiphase fluid and heat flow plays an important role in many problems relating to the disposal of nuclear wastes in geologic media. Examples include boiling and condensation processes near heat-generating wastes, flow of water and formation gas in partially saturated formations, evolution of a free gas phase from waste package corrosion in initially water-saturated environments, and redistribution (dissolution, transport, and precipitation) of rock minerals in non-isothermal flow fields. Such processes may strongly impact upon waste package and repository design considerations and performance.This paper summarizes important physical phenomena occurring in multiphase and nonisother-mal flows, as well as techniques for their mathematical modeling and numerical simulation. Illustrative applications are given for a number of specific fluid and heat flow problems, including: ther-mohydrologic conditions near heat-generating waste packages in the unsaturated zone; repository-wide convection effects in the unsaturated zone; effects of quartz dissolution and precipitation for disposal in the saturated zone; and gas pressurization and flow effects from corrosion of low-level waste packages.

NMR Technique for Multiphase Fluid Study Involving Melting Phenomena

1999 ◽  
Author(s):  
Q. Ni ◽  
J. D. King ◽  
Y.-X. Tao
Keyword(s):  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Melting Rate ◽  
Analysis Method ◽  
Image Analysis Method ◽  
Equilibrium Conditions ◽  
Multiphase Fluid ◽  
Physical Phenomena ◽  
Non Destructive ◽  
Good Agreement

Abstract Nuclear magnetic resonance (NMR) sensors are used to determine the time variation of solid mass for a packed ice bed in an experiment of convective melting under non-thermal equilibrium conditions. The paper describes the basic experimental technique for NAFTM apparatus and feasibility for determining the solid volume fraction and ultimately the melting rate. The NMR technique provides an effective, non-destructive method for multiphase fluid study where phase change is one of the important physical phenomena. The results show a good agreement of data obtained by the NMR method with those from image-analysis method.

scholarly journals Lift force for cylindrical and elliptical Coandă aircraft design

2018 ◽  
Vol 7 (4.13) ◽  
pp. 137
Author(s):  
Mohd Faisal Abdul Hamid ◽  
Azmin Shakrine Mohd Rafie ◽  
Ezanee Gires ◽  
Abd. Rahim Abu Talib
Keyword(s):  
Lift Force ◽  
Control Volume ◽  
Aircraft Design ◽  
The Body ◽  
Viscous Effect ◽  
Extended Version ◽  
Volume Analysis ◽  
Flow Effects ◽  
And Performance ◽  
Rotary Wing

Small aerial vehicles possess advantages in terms of size and accessibility in performing a variety of tasks. Presently, their design and performance is dependent on variations of conventional aerodynamic configurations (fixed- and rotary-wing). A disadvantage for these configurations is the aerodynamic potential between the mainstream airflow and the body surfaces are not fully utilized. To solve this issue, the Coandă effect is proposed whereby a high-velocity jet is blown tangentially over a curved surface to increase circulation and lift. Prior to the costly approach (experimental and numerical), an analytical formulation (via control volume analysis) to predict the aerodynamic Coandă lift force of the design concept is developed. This is an extended version of the existing mathematical formulations, capturing viscous flow effects. It is also pertinent for circular and elliptical-shaped designs. The results obtained show that the total lift force is dependent on the jet velocity, outflow angle, dimensions of the jet slot, the projected surface area, and the viscous effect. The approach has demonstrated how this modelling technique is effective in calculating the lift force for cylindrical and elliptical Coandă aircraft design.   

Vp/Vs in unconsolidated oil sands: Shear from Stoneley

Geophysics ◽  
1987 ◽  
Vol 52 (4) ◽  
pp. 502-513 ◽  
Author(s):  
Brian E. Hornby ◽  
William F. Murphy
Keyword(s):  
Heavy Oil ◽  
Oil Sands ◽  
Waveform Analysis ◽  
The Core ◽  
Full Waveform ◽  
Fluid Saturation ◽  
Saturated Formations ◽  
Compressional Mode ◽  
Water Saturated ◽  
Compressional Velocity

The SDT-A sonic tool was tested in a borehole in the Orinoco heavy oil belt, eastern Venezuela. The sonically slow reservoir consists of unconsolidated quartz sand interbedded with shale. Full‐waveform analysis yields both compressional and shear slownesses. We calculated the shear‐wave slowness from the Stoneley slowness; compressional and Stoneley slownesses were determined using modified semblance techniques. The compressional velocity is relatively fast in the heavy oil pay zone compared to the remainder of the well. Heavy oil (8 API) possesses a finite rigidity at sonic frequencies, and the rigidity of the hydrocarbon adds to the stiffness of the poorly consolidated sand. The sand would not otherwise yield such a high velocity. Compressional and shear velocities of samples from eight whole cores were measured in the laboratory, and the core velocities were found to be consistent with the logs. Especially encouraging is the agreement of the laboratory shear with the shear log derived from Stoneley. The ratio of the compressional‐to‐shear velocities, [Formula: see text], is sensitive to fluid saturation and rock fabric. The oil sands have a [Formula: see text] of less than 2.5. The shales in the well have a [Formula: see text] of greater than 2.5. We found that water‐saturated formations are governed by Biot’s theory, while oil sands are better described by scattering theory. A third arrival has been identified as a leaky compressional mode trapped in the borehole. The velocity of the mode is dominated by the slowness of the borehole mud.

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