摘要

The pool boiling heat transfer performance of plain tubes and bronze sintered porous surface tubes immersed in deionized water were studied experimentally at subatmospheric pressures. Experiments were performed at reduced pressures from 3 to 50 kPa and heat flux values from 16.7 to 50 kW/m². The heat transfer coefficients on both plain tubes and tubes with bronze sintered porous surface increase with the heat flux and pressure. The relationship between the heat transfer coefficient, heat flux, and pressure is described by equations. At subatmospheric pressures, the porous surface tube enhanced the boiling heat transfer signifi cantly. A factor for enhanced boiling of water on bronze sintered porous surface tubes was determined. Moreover, the bundle effect at subatmospheric pressures was considered in the present work. The results confirmed that the bundle effect remains in a vacuum and can improve the heat transfer coefficient on plain tubes as well as on bronze sintered porous surface tubes.