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Analysis of the mist lift process for mist flow open-cycle OTEC

Description: Preliminary results are presented of a numerical analysis to study the open-cycle mist flow process for ocean thermal energy conversion (OTEC). Emphasis in the analysis is on the mass transfer and fluid mechanics of the steady-state mist flow. The analysis is based on two one-dimensional models of the mist lift process: a single-group model describes a mist composed of a single size of drops and a multigroup model considers a spectrum of drop sizes. The single-group model predicts that the lift achieved in the mist lift process will be sensitive to the inlet parameters. Under conditions that lead to maximum lift in the model for a single drop size, the multigroup model predicts significantly reduced performance. Because the growth of drops is important, sensitivity of the predicted performance of the mist lift to variations in the collision parameters has been studied.
Date: June 1, 1980
Creator: Davenport, R. L.
Partner: UNT Libraries Government Documents Department

Mist lift analysis summary report

Description: The mist flow open-cycle OTEC concept proposed by S.L. Ridgway has much promise, but the fluid mechanics of the mist flow are not well understood. The creation of the mist and the possibility of droplet growth leading to rainout (when the vapor can no longer support the mist) are particularly troublesome. This report summarizes preliminary results of a numerical analysis initiated at SERI in FY79 to study the mist-lift process. The analysis emphasizes the mass transfer and fluid mechanics of the steady-state mist flow and is based on one-dimensional models of the mist flow developed for SERI by Graham Wallis. One of Wallis's models describes a mist composed of a single size of drops and another considers several drop sizes. The latter model, further developed at SERI, considers a changing spectrum of discrete drop sizes and incorporates the mathematics describing collisions and growth of the droplets by coalescence. The analysis results show that under conditions leading to maximum lift in the single-drop-size model, the multigroup model predicts significantly reduced lift because of the growth of droplets by coalescence. The predicted lift height is sensitive to variations in the mass flow rate and inlet pressure. Inclusion of a coasting section, in which the drops would rise ballistically without change in temperature, may lead to increased lift within the existing range of operation.
Date: September 1, 1980
Creator: Davenport, R.L.
Partner: UNT Libraries Government Documents Department

Ocean energy conversion systems annual research report

Description: Alternative power cycle concepts to the closed-cycle Rankine are evaluated and those that show potential for delivering power in a cost-effective and environmentally acceptable fashion are explored. Concepts are classified according to the ocean energy resource: thermal, waves, currents, and salinity gradient. Research projects have been funded and reported in each of these areas. The lift of seawater entrained in a vertical steam flow can provide potential energy for a conventional hydraulic turbine conversion system. Quantification of the process and assessment of potential costs must be completed to support concept evaluation. Exploratory development is being completed in thermoelectricity and 2-phase nozzles for other thermal concepts. Wave energy concepts are being evaluated by analysis and model testing with present emphasis on pneumatic turbines and wave focussing. Likewise, several conversion approaches to ocean current energy are being evaluated. The use of salinity resources requires further research in membranes or the development of membraneless processes. Using the thermal resource in a Claude cycle process as a power converter is promising, and a program of R and D and subsystem development has been initiated to provide confirmation of the preliminary conclusion.
Date: March 1, 1981
Partner: UNT Libraries Government Documents Department

Development of a Foam OTEC System. Final technical report for Fiscal Year 1979

Description: Research on Development of a Foam OTEC System, as carried out at Carnegie-Mellon University from October 1, 1978 through September 30, 1979, is described. To a brief section summarizing highlights of research results are appended 12 technical reports which detail specific sections of the program. The work described is continuing and a proposal is currently being submitted to provide support in fiscal 1980.
Date: January 1, 1980
Partner: UNT Libraries Government Documents Department