10 Matching Results

Search Results

Advanced search parameters have been applied.

Transient compressible flows in porous media

Description: Transient compressible flow in porous media was investigated analytically. The major portion of the investigation was directed toward improving and understanding of dispersion in these flows and developing rapid accurate numerical techniques for predicting the extent of dispersion. The results are of interest in the containment of underground nuclear experiments. The transient one-dimensional transport of a trace component in a gas flow is analyzed. A conservation equation accounting for the effects of convective transport, dispersive transport, and decay, is developed. This relation, as well as a relation governing the fluid flow, is used to predict trace component concentration as a function of position and time. A detailed analysis of transport associated with the isothermal flow of an ideal gas is done. Because the governing equations are nonlinear, numerical calculations are performed. The ideal gas flow is calculated using a highly stable implicit iterative procedure with an Eulerian mesh. In order to avoid problems of anomolous dispersion associated with finite difference calculation, trace component convection and dispersion are calculated using a Lagrangian mesh. Details of the Eulerian- Lagrangian numerical technique are presented. Computer codes have been developed and implemented on the Lawrence Livermore Laboratory computer system. (TFD)
Date: September 1, 1975
Creator: Morrison, F.A. Jr.
Partner: UNT Libraries Government Documents Department

Scoping analysis for radionuclide migration test

Description: The Lawrence Livermore National Laboratory is to conduct an in situ test of radionuclide migration in fractured granite. Radionuclides are to be injected into a fracture in the Climax Stock of the Nevada Test Site, then transported by fluid motion and subsequently withdrawn. The fluid will be injected through a borehole intersecting a near vertical fracture and withdrawn through a second borehole that intersects the fracture directly below the first. The scoping calculations presented here are intended to aid planning this experiment. In the absence of a detailed fracture description, this analysis treats the fracture as the space between parallel flat plates; the flow is a Hele-Shaw flow. The calculations predict the conditions for breakthrough of radionuclides at the outlet hole and describe the subsequent concentration history of fluid flowing from the fracture. The effects of advection, sorption, and geometric dispersion are treated.
Date: January 1, 1982
Creator: Morrison, F.A. Jr.
Partner: UNT Libraries Government Documents Department

Stability of flow from a nuclear cavity. Final report. [GANDLF]

Description: The stability of flow from a nuclear cavity was examined. The flow of interest consists of air and steam at high pressure and temperature moving through a porous medium. The steam condenses at a moving front. The stability of the flow was analyzed using the normal mode method and a program was written to perform the necessary calculations. Results of the computer calculations show that the flow of interest is stable and any instabilities that occur will decay slowly. Stability was influenced by gravity, fluid mobilities, and condensation. It was found that the stabilizing effect of conductivity is only important at negligibly small wavelengths.
Date: July 1, 1977
Creator: Morrison, F.A. Jr.
Partner: UNT Libraries Government Documents Department

Transient high speed gas flow in a gravel stemming column. [BANDICOOT Event]

Description: Transient high speed gas flow up a gravel stemming column was investigated. The results provide an upper bound to the extent of gas pressure propagation in the first several seconds following an underground nuclear test. Application of these results to the LASL BANDICOOT event demonstrate that gas flow through the gravel column cannot explain that vent.
Date: February 9, 1979
Creator: Morrison, F.A. Jr.
Partner: UNT Libraries Government Documents Department

Transient gas or liquid flow along a preexisting or hydraulically-induced fracture in a permeable medium

Description: Similarity solutions are derived for the trasient two-dimensional flow of a gas or liquid along an isolated fracture in a permeable medium. The driving pressure at the fracture inlet is constant, and the confining stress is uniform. Two different cases are considered, pre-existing fractures with uniform aperture as well as hydraulic fractures with a variable aperture proportional to the local overpressure (fluid pressure less confining stress). The evolution of the pressure distribution is described by a set of four asymptotic solutions, each having a self-similar form. At early times the flow in the fracture is turbulent, and Darcian seepage losses into the porous surroundings are negligible. At late times the flow in the fracture is laminar, and seepage losses become a dominant consideration. At intermediate times there are two alternative asymptotes, depending upon physical parameters. The mathematical model also describe the flow along a fracture which is fulled with high-permeability porous material as well as the flow in an assemblage of porous blocks. 19 refs., 10 figs.
Date: May 1, 1985
Creator: Nilson, R.H. & Morrison, F.A. Jr.
Partner: UNT Libraries Government Documents Department

Permeability of granular beds emplaced in vertical drill holes

Description: To determine the permeabilities of granular materials emplaced in vertical drill holes used for underground nuclear tests, an experiment at the USDOE Nevada Test Site (NTS) was conducted. As the hole is being filled, falling material increases pressure above and within the granular beds beneath. When the filling operation starts or stops, a transient pressure response occurs within the beds; measurements of this response in beds of various compositions were made. The permeabilities after emplacement were found by matching analytical predictions of the response to these data. This information is useful in assuring the containment of nuclear tests conducted in such drill holes.
Date: February 23, 1979
Creator: Griffiths, S.K. & Morrison, F.A. Jr.
Partner: UNT Libraries Government Documents Department

Flow of cavity gas along fractures, cable bundles, and grouted cables

Description: Analytical and numerical solutions are presented for gas flow along isolated fractures in permeable media. Two different cases are considered: preexisting fractures with a uniform aperture, as well as hydraulically-driven fractures with a variable aperture which is proportional to the local overpressure (local fluid pressure less confining stress). Results for these two geometries are compared with one another and with results for wedge-shaped and penny-shaped fracture geometries. Application to underground nuclear testing is illustrated by a number of examples including: flow along shock-induced and hydraulically-induced fractures, seepage along single electrical cables surrounded by grout, and flow along a bundle of electrical cables surrounded by granular stemming material. 15 refs., 13 figs.
Date: January 1, 1985
Creator: Nilson, R.H. & Morrison, F.A. Jr.
Partner: UNT Libraries Government Documents Department