A general theory of flooding implementing the cuspoid catastrophe

• Main Author: Lafi, Abd Y.
• Other Authors: Reyes, Jose N. Jr
• Language: en_US
• Published: 2013
• Subjects: Nuclear reactors > Fluid dynamics; Catastrophes (Mathematics); Two-phase flow
• Online Access: http://hdl.handle.net/1957/37475

The flooding phenomenon can be defined as the maximum attainable flow condition beyond which the well defined countercurrent flow pattern can no longer exist. Thus the countercurrent flow limit (CCFL) or the flooding limit may be thought of as the flow condition at which the strong interaction between the two phases occurs. Considerable effort has been devoted to understanding and analyzing the flooding transition in many fields. For example; the flooding phenomenon is one of the important phenomena encountered in the safety analysis of light water reactors (pressurized water reactors and boiling water reactors). Accurate predictions of flooding behavior are particularly important in the assessment of emergency core cooling system (ECCS) performance. Currently, the postulated loss-of-coolant accident (LOCA) is considered the design basis accident. A physical understanding of the flooding phenomenon will help assess core refill during the course of a LOCA. Understanding the physical mechanisms of the flooding phenomenon might help establish more reliable equations and correlations which accurately describe the thermal hydraulic behavior of the system. The models can provide best-estimate capability to the design codes used in the evaluation of ECCS performance. The primary concern of this study was to: 1. Understand the physical mechanisms involved in the flooding phenomenon in order to derive a suitable analytical model. 2. Show that the combination of: a. Linear Instability Theory b. Kinematic Wave Theory c. Catastrophe Theory can provide a general model for flooding phenomenon. The theoretical model derived using the aforementioned combination of theories indicates good agreement between the experimental and the predicted values. Comparisons have been made using a large volume of air-water flooding data. === Graduation date: 1991