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Experimental and Theoretical Studies of Liquid Injection into Vapour-Dominated Reservoirs

Description: We analyze the injection of liquid into a depleted geothermal reservoir using numerical, analytical and experimental techniques. We first investigate the injection of liquid at the base of a uniformly heated reservoir and show how an ascending liquid layer develops. Ahead of the liquid-vapor interface the temperature rises sharply and, for cases in which the permeability is sufficiently high, the vapor is approximately isobaric. The region immediately behind the advancing liquid-vapor interface is approximately isothermal and therefore, the fraction vaporizing is dependent on the reservoir superheat. When the reservoir is overlain by a supercooled zone, some of the vapor produced at the ascending liquid-vapor interface condenses. As a result, the amount of newly formed vapor available for subsequent extraction can be significantly reduced.
Date: January 1, 1995
Creator: Fitzgerald, S.D. & Woods, W.
Partner: UNT Libraries Government Documents Department

Viscous fingers in superheated geothermal systems

Description: In this paper we investigate the physical controls upon the rate of vaporization of liquid as it is injected into a porous layer containing superheated vapor. We develop a simple model of the process and show that if liquid is injected at a relatively high rite, a small fraction of the liquid vaporizes and the porous layer becomes filled with hot liquid. In contrast, at low rates of injection a large fraction of the liquid may vaporize. We also describe a new and fundamental instability that can develop at a migrating liquid-vapour interface if the rite of injection is sufficiently small. This phenomenon is manifest in the form of liquid fingers growing from a liquid-vapour interface and is investigated through the use of analytical, experimental and numerical techniques.
Date: January 1, 1995
Creator: Fitzgerald, S. D.; Woods, A. W. & Shook, M.
Partner: UNT Libraries Government Documents Department

A directory service for configuring high-performance distributed computations

Description: High-performance execution in distributed computing environments often requires careful selection and configuration not only of computers, networks, and other resources but also of the protocols and algorithms used by applications. Selection and configuration in turn require access to accurate, up-to-date information on the structure and state of available resources. Unfortunately, no standard mechanism exists for organizing or accessing such information. Consequently, different tools and applications adopt ad hoc mechanisms, or they compromise their portability and performance by using default configurations. We propose a Metacomputing Directory Service that provides efficient and scalable access to diverse, dynamic, and distributed information about resource structure and state. We define an extensible data model to represent required information and present a scalable, high-performance, distributed implementation. The data representation and application programming interface are adopted from the Lightweight Directory Access Protocol; the data model and implementation are new. We use the Globus distributed computing toolkit to illustrate how this directory service enables the development of more flexible and efficient distributed computing services and applications.
Date: August 1, 1997
Creator: Fitzgerald, S.; Kesselman, C. & Foster, I.
Partner: UNT Libraries Government Documents Department