摘要
目前，普遍认为蒸发段内工质的流动型式依次为单相液流、弹状流、泡状流及环状流．通过可视化试验和壁温测量，分析了蒸发段工质的流动规律，发现在保证热管工作的条件下，其蒸发段工质的流动型式除单相液流和泡状流外，还存在有一种称之为飞溅降膜流的流型，它对热管的蒸发换热有很大的影响．试验表明，在飞溅降膜区内汽泡夹带液滴向上飞溅的频率及高度均与热流密度有关，当热流密度ｑ≥２０ｋｗ／ｍ￣２，频率稳定在ｆ＿０＝０．８Ｗ２４Ｈｚ（ｔｖ＝１００℃）时，飞溅高度保持在蒸发段有效长度的４２％～５０％．分离式热管的这种流动特性是确定其合理充液率及传热特性的重要依据．
In recent years,many researchers are interested in separate heat pipes for their variousadvantages. The now patterns in evaporators were generally defined as single-phase liquidnow,slug now,bubble flow and annular flow. In this paper,a simulated evaporator of separate type thermosyphon is set up by heating a silica glass tube. According to the observationand experimental data,it is found that besides some flow patterns mentioned above,there isan unstable splash dowmwards flowing liquid film region in the top of the evaporator if theefficiency and reliability of heat pipes ace ensured. And the frequency and height that bubblesentraining water droplets splash upward depend on heat fluxes. When heat fluxes q>20kW/m2,the frequency is stable at f=0. 824 Hz(t=100 ℃ ),the splash height is 42 % ～50%of the efficient length of the evaporator. The splash flow is a special flow pattern in the separated type heat pipe evaporator and is an important basis for determining the optimum fillingcondition and heat transfer characteristics of heat pipes.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
1996年第5期117-121,共5页
Journal of Xi'an Jiaotong University
