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Browsing by Author "Warren, Jeffery Howard"

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    Design analysis of a drilled geothermal well
    Warren, Jeffery Howard (Virginia Polytechnic Institute and State University, 1974)
    An insulated coaxial pipe for a 50,000 ft drilled geothermal well was designed, in order to remove heat from the earth's crust by the circulation of water through a single well. The design took into consideration means of insulating and supporting the inner pipe, thermal expansion, the large hydrostatic pressures involved, and a feasible means of installing the ten mile pipe. A thermodynamic analysis of the aboveground power generation system, including a once-through steam generator, condenser, circulating pumps, and a feed-water heater system, was made in order to obtain the maximum thermal efficiency. The drilled geothermal power generation equipment is different from that of conventional fossil or nuclear-fired equipment in that the water temperature arriving at the wellhead is continuously varying due to the removal of heat from the earth's crust. Due to the fact that the earth is a poor conductor of heat, continuous operation of the well results in the water at the wellhead falling below an acceptable power generation temperature after a relatively short time period. Therefore, intermittent operation of several wells in staggered fashion using the same aboveground power generation equipment is required. A determination of the well operating characteristics including optimum mass flow and well cut-on and cut-off temperatures was made. From this a justifiable well cost was determined in order to provide geothermal electrical power and process heat at a reasonable cost.
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    A prediction of polymer wear using polymer mechanical properties and surface characterization parameters
    Warren, Jeffery Howard (Virginia Tech, 1976-08-15)
    Polymers were slid on rough hard steel surfaces with normal loads which caused full penetration (real and apparent areas equal) and partial penetration (real less than apparent area). Wear data for polyvinylchloride (PVC) and polychlorotrifluoroethylene (PCTFE) was obtained on a pin-on-disk machine using neutron activation analysis A (NAA). Observations of the wear process were made in the scanning electron microscope (SEM) both before, during, and after the wear experiment. It was observed that these polymers along with Nylon 6-6 tend to wear in discrete sites rather than continuous films. At these discrete sites the polymer shears at an angle which is dependent on the mechanical properties of the polymer and on the asperity angle. There appears to be a minimum shear angle beyond which no wear occurs.