STUDY ON HEAT TRANSFER OF HIGH-PRESSURE STEAM-WATER TWO-PHASE MIXTURE IN HELICAL COILS

摘要

Experiments of steam-water two-phase boiling heat transfer in a vertical helically-coiled tube were carried out in high-pressure water test loop of Xi'an Jiaotong University. The coil was constructed from lCrl8Ni9Ti stainless steel tube with 3800mm length, 20mm O.D. and 16mm I.D. Its helix diameter is 1300mm, and helix angle is 3.65°. The experimental conditions covered in tests are: pressure p=4-19 MPa, mass velocity G=400-1400 kg/(m~2 ·s), inner wall heat flux q=100-700 kW/m~2. Wall temperature profiles along the tube length and around the tube perimeter were recorded. On the bases of these data, the critical qualities of CHF and convection heat transfer coefficients were obtained. A general correlation for predicting the heat transfer coefficients was derived. The correlation is in good agreement with the experimental data.