Post-dryout heat transfer for vertical narrow annular channel

This investigation is conducted with deionized water flowing through a narrow annular channel heated electrically on the outside and inside under pressures of 1.5 MPa and 3.0 MPa and at high temperature. The post-dryout forced convective heat transfer was examined experimentally. The results show that the heat transfer behaviors in the annular gap are dissimilar to that in the convectional macro channels or tubes. Based on the experiment data, the Groeneveld equation and Polomik equation were developed. A heat transfer equation using the ratio of the bigger heat flux on inside and outside tube with their sum was developed. The calculated results for low flow rate are compatible to the experiment data.