【摘要】 在亚临界及近临界压力下,对Φ32×3mm 不锈钢倾斜上升光管(倾角α=20°)及垂直上升光管中水的沸腾传热特性进行了试验研究。试验参数范围:压力 p=13~21.5MPa,质量流速 G=600~1200kg/(m2s),内壁热负荷 q=200~600kW/m2。试验结果表明:倾斜管比垂直管更容易发生第一类传热恶化(DNB),但倾斜管发生 DNB 后的壁温飞升峰值低于垂直管;倾斜管与垂直管类似,增加质量流速可以提高临界热负荷,在近临界压力区比亚临界压力区更容易发生DNB。提出了对超临界锅炉设计有重要参考价值的倾斜管临界热负荷、垂直管及倾斜管最小传热系数的计算关联式。更多还原

【Abstract】 At sub-critical and near critical pressures, the boiling heat transfer characteristics of water in the inclined upward smooth tube of the inclined angle of α=20° and the vertical upward smooth tube with the diameter of Φ32×3mm were researched experimentally. The tests were performed at p=13~21.5MPa, G=600~1200kg/(m2s) and q=200~600kW/ m2。The results show that the departure from nucleate boiling (DNB) occurs more easily in the inclined tube than in the vertical tube, and that the peak wall temperature after DNB on the inclined tube is lower than that on the vertical tube. An increase of the mass velocity can increase the critical heat flux in the inclined tube, which is similar to that in the vertical tube. DNB occurs more easily in near critical pressure region than in sub-critical pressure region. The equation of the critical heat flux on the inclined tube and the equations of the minimum heat transfer coefficients on both tubes have been provided and can be used as a reference in the design of supercritical pressure boilers.更多还原