CHARACTERISTICS OF CRITICAL HEAT-FLUX IN 2-PHASE THERMOSIPHON - RELATIONSHIP BETWEEN MAXIMUM FALLING LIQUID RATE AND INSTABILITY ON INTERFACE OF FALLING LIQUID-FILM

Critical heat flux in a two-phase thermosyphon is usually dealt with f rom two different ways in a limitation of liquid flow rate falling alo ng a vertical tube: one is a maximum falling liquid rate due to the en velope method, and the other one due to instability of falling liquid film. The difference between the maximum and instability criteria is f irst made clear. The CHF in the thermosyphon is shown to be predicted well by the maximum liquid rate due to the maximum criterion better th an due to the instability criterion. In addition, the comparison impli es that the CHF phenomenon in the thermosyphon is considered to be cau sed when the falling liquid reaches the maximum value rather than when the instability of the falling liquid on the interface is brought abo ut.