Inverted Annular Film Boiling Model Analysis

Open Access
Author:
Li, Zhiyu
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 29, 2013
Committee Members:
  • Fan Bill B Cheung, Thesis Advisor
Keywords:
  • heat transfer
  • two-phase heat transfer
  • inverted annular film boiling
Abstract:
ABSTRACT Theoretical and experimental investigations conducted in the field of Inverted Annular Film Boiling (IAFB) have led to considerable developments. The heightened interest in IAFB is also attributed to the increased importance of the same in a variety of practical applications across various industries. The occurrence of critical heat flux prompts an abrupt increase in the wall temperature which is further responsible for a physical burnout of the heated surface. IAFB conditions are usually not present during normal operations in nuclear reactors, but can be encountered in case of an accident following a loss of coolant. Experiments for measuring IAFB are not easy in conventional heat flux controlled systems and as a result different models and experiments need to be conducted. As a part of this thesis, different methods have been discussed for the purpose of conducting experiments. The data has been collected from 10 experiments involving reflood heat transfer performed in The Pennsylvania State University/U.S. Nuclear Regulatory Commission Rod Bundle Heat Transfer (RBHT) Test Facility. Measurements were taken for heater rod temperatures, bundle power, upper plenum pressure, inlet flow rate and inlet subcooling, superheated vapor temperatures in the bundle, liquid carryover, spacer grid temperatures and axial bundle pressure drop. The results obtained from the reflood data were used as a basis for developing and accessing the model. Many theoretical and experimental models have been developed for IAFB, as many heat transfer coefficient correlations have been proposed to predict the experimental data. In this work, all the important theoretical models applicable to IAFB are reviewed and the major correlations for IAFB are evaluated by comparing them with experimental data in order to identify the most optimized correlation.