Inaug.-diss.--Basel.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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During a loss of coolant accident in a pressurised water reactor, emergency core cooling water is introduced via the downcomer annulus. The water may have to penetrate or overcome steam formed in the vessel due to the depressurisation. A typical counter-current flow situation can be created and dependent on the relative flow rates water may be prevented from reaching the reactor core with serious consequences. This,thesis considers the events leading up to this occurrence in a vertical, 54.75 mm diameter, 1 m long, stainless steel tube, to represent and provide a basic understanding of the situation occurring during a loss of coolant accident. Results are presented for air-water and steam-water flows with emphasis on the experimental and theoretical studies of the steam-water flow situation where direct contact heat transfer occurs. The air-water flooding data are shown to be well represented by a Wallis type flooding correlation. The steam-water flooding data are found to lie above the corresponding air-water data with their characteristic dependent on the water inlet subcooling. The percentage of the air/steam flow extracted with the water flow at the bottom porous sinter was found to exert a negative effect on the flooding phenomena. A theoretical model was developed to predict the liquid film thickness along the tube, and agreement with the experimental results demonstrated. A second theoretical model was developed to evaluate the temperature across the liquid film and along the test tube and from this model, the effective turbulent diffusivity was evaluated, leading to an estimate of the turbulent viscosity of the film under conditions in which substantial condensation took place. A semi-empirical model based on a linear stability analysis of a uniform liquid film and a counter-current flow of steam, was developed and modified for accelerating film flows. This model is shown to be capable of dealing with the steam-water flooding situation since reasonable agreement with the air-water flooding data is obtained. A modified Wallis type flooding correlation based on the experimental data, and accounting for non-equilibrium effect on flooding, is presented and discussed. A visualisation technique was developed and used to determine the flooding location in the section.

Master thesis is dealing with the issue of condensate creation and removal from the Nesher Ramle steam turbine during start-up and steady state. At the beginning a preliminary calculation of heat balance and the turbine itself is done. It is followed by description and design of drainage system supplemented by calculation of the steam flow through the orifices. Steam flow calculation was done via S. D. Morris, Pavelek with Kalčík and Ambrož, all three methods were compared. The main goal is the theoretical calculation of the amount of condensate created during start-up which is influenced by its initial state from which it is started. Three default states are considered, cold, warm and hot. In the last chapter the comparison of theoretical calculation with the measured data on real turbine is done and it is supported by the evaluation of the data from the measurement of the steam turbine at steady state on maximum power and half power. From the steady state analysis, percentage of water flow to expander from the total amount of condensate formed in the turbine were obtained.

The dissertation analyses a possibility to install a steam turbine for steam reduction in the heating plant with a combined cycle, Červený Mlýn. In the first part of this work the constituent parts of Červený Mlýn plant are briefly described. Basic information is included about two considered solutions to the steam turbine for steam reduction. Then the thermic diagram of the whole heating plant and the heat exchanger station itself is presented. On the basis of the given values of the heat required in the hydrothermal system, duration of the steam flow through both variants of the steam turbine for steam reduction is determined. The thermodynamic calculation of the steam turbine for steam reduction is aimed at determination of the power output and its comparison with the power outputs of the steam turbines for steam reduction considered. In the economical profitability calculation, basic economical quantities are given for both the solutions and the more suitable solution is recommended.