侧载和管径对管内沸腾两相流性能影响实验

Experiment on the effects of side load and pipe diameter on the characteristics of boiling two-phase pipe flow

为研究飞行过程中侧向载荷对不同管径内沸腾两相流流动和传热的影响,在自行搭建的实验平台上做了多次实验.通过对实验段内流体的压差、雷诺数、孔隙率、热流密度及传热系数等参数数据的处理分析,研究了侧载和管径对管内沸腾两相流性能的影响.结果表明,动载越大,管内压差越大,管外散热越强,流体流量越小,空隙率越低,流体得热的热流密度越低.动载荷加强了单相流的表面传热系数;但对于沸腾两相流有一个先抑制再增强最后削弱的过程.管径对雷诺数、压差、孔隙率、散热能力等也有显著的影响,较小的管径流动阻力较大,而换热能力则有所提升.

Serial experiments were conducted to obtain the flow and heat transfer characteristics of boiling two-phase pipe flow under different diameters and side load.By analyzing the measured parameters such as pressure drop,Reynolds number,void fraction,heat flux and heat transfer coefficient in the test pipe,the effects of side load and pipe diameter on the characteristics of boiling two-phase flow were studied.The results show that the greater the side load,the higher the pressure drop,the heat dissipation,and the lower the flow rate,the void fraction and the heat flux.Dynamic load increases the heat transfer coefficient for single-phase water flow.However for boiling two-phase flow,with the increase in side load,the heat transfer coefficient decreases somewhat first,then increases and finally decreases again.Pipe diameter also has great influence on Reynolds number,pressure drop,void fraction and heat dissipation.The pipe with smaller diameter has a larger flow resistance,and good heat exchange ability.