【摘要】 在压力p=12~32MPa,质量流率G=741~2294 kg/(m~2·s),内壁热负荷q(28)200~870 k W/m~2的参数范围内,以水为工质,对水平倾角25°的倾斜上升光管的传热特性进行了试验研究。试验结果表明:浮力作用是倾斜管传热的重要影响因素。热负荷对传热具有多重影响。在亚临界压力区,质量流率增量具有界限值,其影响与垂直管中的界限质量流率有所不同。在近临界压力区,增大质量流率或降低热负荷能推迟传热恶化的发生;宏观对流作用可以改善恶化后的传热。在超临界压力区,超临界水的物性变化作用不能减小倾斜管的周向不均匀性。更多还原

【Abstract】 Heat transfer characteristics of an inclined smooth tube with upward flow was experimentally investigated under the parametric range of pressure from 12~32MPa, mass flux from 741~2294kg/(m2·s), inner wall heat flux from 200~870k W/m2. The working medium was water. The inclination angle was 25° from the horizon. Experimental results show that buoyancy force plays an important role in heat transfer of the inclined tube. Multiple impacts of heat flux on heat transfer are observed. At subcritical pressures, a critical value in mass flux increment is detected, which exhibits distinguish influence to the critical mass flux observed in the vertical tube. At near critical pressures, heat transfer deterioration can be delayed by increasing mass flux or reducing heat flux; post-deterioration heat transfer conditions can be improved by the macroscopic convection. At supercritical pressures, sharp variation of thermal physical properties of supercritical water shows little contribution to the reduction of circumferential non-uniformity of the inclined tube.更多还原