动载对管内沸腾两相流传热特性的影响

Effects of dynamic load on the heat transfer characteristics of two-phase pipe boiling flow

对旋转状态下的单相水及加热单相水至沸腾的两相流进行了对比实验.通过对热耗散、流型、流阻及传热的分析与计算,研究了动载对流体流动与传热的影响.结果表明:过载强烈影响两相流动(尤其是流阻)和热传递方式,增大了流体的流阻和热损失,并削弱了流体的得热能力.动载引起的冲击交混流改变了管壁温度的均匀性和变化规律,即随着过载的增大,在一定范围内,管壁底部温度降低,顶部温度升高.

An experimental investigation was performed comparatively and heat transfer characteristics of single-phase water flow and two-phase to obtain the flow pipe boiling water flow under dynamic toad in present work. By analyzing the effective heat, flow pattern, fluid resistance and heat transfer coefficient of the experimental data, the effects of dynamic load on the flow and heat transfer characteristics of single phase water and two-phase boiling water flow were investigated. The results show that the dynamic load significantly influences the flow characteristic and boiling heat transfer of the two-phase pipe flow. It will enhance the fluid resistance and heat dissipation toward the ambient environment, and also reduce the heat transfer capability of the two-phase boiling flow. The impact mixing flow caused by the dynamic load breaks the uniform and varying properties of the wall temperatures, so the greater the dynamic load, the lower the wall inner bottom temperature, and the higher the wall inner top temperature occurs in a certain extent