TED-AJ03-623 THE BEHAVIOR OF INVERTED FLOW FILM BOILING DURING THE REFLOOD PROCESS

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概要

• 論文の詳細を見る

• As a nuclear rod bundle rapidly refloods following a postulated Loss of Coolant Accident (LOCA), inverted annular film boiling occurs on the heated surface. Inverted Annular Film Boiling (IAFB) is characterized by a thin vapor film covering the heating surface, which separates the liquid core, which is at or below saturation temperature from the heated surface. IAFB involves convective heat transfer from the hot wall to the vapor blanket and from the vapor to the liquid core. Heat may also be transferred directly from the hot rods to the liquid core by radiation. The heat transfer coefficient associated with this mode of film boiling is high primarily because of the thin vapor layer which separates the heated surface and the liquid core. As the heated bundle refloods, the void fraction changes from near zero to very high values as the flow regime transitions into dispersed fow film boiling. The heat transfer decreases as the void fraction and the vapor content of the flow increases. The models incorporated in Best-Estimate thermal hydraulic codes for the modeling the IAFB region use the modified form of the Bromley equation with the hydraulic diameter as the characteristic length dimension. The hydraulic diameter is a constant and therefore, the heat flux calculated is also a constant for a given pressure, and independent of the location of the quench front. This is contrary to what is expected physically and also observed experimentally. The present effort focuses on developing a more realistic length scale for use in the calculation of the heat transfer coefficient. The Bromley model is used along with the data from the FLECHT-SEASET experiments to obtain the heat transfer coefficient. Unlike what is currently used in the Best-estimate codes, the prediction shows the same trend as the experimental data.

• 社団法人日本機械学会の論文

著者

• Sridharan Arunkumar

  Department Of Mechanical And Nuclear Engineering The Pennsylvania State University

• Hochreiter Lawrence

  Department of Mechanical and Nuclear Engineering The Pennsylvania State University

• Cheung Fan

  Department of Mechanical and Nuclear Engineering The Pennsylvania State University

• Cheung Fan

  Department Of Mechanical And Nuclear Engineering Pennsylvania State University

• Hochreiter Lawrence

  Department Of Mechanical And Nuclear Engineering Pennsylvania State University

関連論文

• TED-AJ03-623 THE BEHAVIOR OF INVERTED FLOW FILM BOILING DURING THE REFLOOD PROCESS
• TED-AJ03-624 Droplet Size and Velocity Measurements in a Heated Rod Bundle

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