MODES OF CIRCULATION IN AN INVERTED U-TUBE ARRAY WITH CONDENSATION.

AN EXPERIMENT AND ANALYSIS WERE PERFORMED ON AN INVERTED U-TUBE STEAM CONDENSER (SIMILAR TO A STEAM GENERATOR) TO DETERMINE THE MODES OF FLOW THAT CAN EXIST AS THE RATE OF STEAM FLOW INTO THE CONDENSER IS REDUCED. THE CONDENSER CONSISTED OF FOUR GLASS TUBES CONNECTED TO A COMMON INLET PLENUM AND A COMMON EXIT PLENUM. HEAT-TRANSFER AND FLOW-RATE MEASUREMENTS, AS WELL AS VISUAL OBSERVATIONS WERE MADE. FOUR DIFFERENT MODES OF OPERATION WERE IDENTIFIED. NONCONDENSABLES WERE FOUND TO SUBSTANTIALLY ALTER THE PLENUM TO PLENUM PRESSURE DIFFERENCE AND AID FLOW STABILITY. SATISFACTORY ANALYTICAL DESCRIPTIONS OF THE OBSERVATIONS HAVE BEEN DEVELOPED AS WELL AS APPLICATION OF THE RESULTS TO THE CONDENSING BEHAVIOR OF NUCLEAR STEAM GENERATORS UNDER ABNORMAL OPERATING CONDITIONS.