CAJ | 학술논문

在蒸发温度为5~15℃，工质质量流速变化范围为50~500 kg/(m2?s)，热流密度范围为5~25 kW/m2和干度范围为0.01~0.9的条件下，对R134a在卧式螺旋管内沸腾两相流型及壁温特性进行了实验研究。利用可视化技术对流型进行了观察分析，发现在相同工况条件下，卧式螺旋管上升段和下降段的流型有所不同，特别是形成环状流之前存在明显不同的过渡流型，分别为“波环状流型”和“超大气弹流型”，因此，对上升段和下降段分别建立了流型图。分别获得了卧式螺旋管沿管长和沿螺旋管横截面圆周方向的壁面温度分布特性。壁面温度沿管长呈逐渐降低的趋势；沿横截面圆周方向，最外侧壁温最低，最内侧壁温最高，两侧温度居中。
재증발온도위5~15℃，공질질량류속변화범위위50~500 kg/(m2?s)，열류밀도범위위5~25 kW/m2화간도범위위0.01~0.9적조건하，대R134a재와식라선관내비등량상류형급벽온특성진행료실험연구。이용가시화기술대류형진행료관찰분석，발현재상동공황조건하，와식라선관상승단화하강단적류형유소불동，특별시형성배상류지전존재명현불동적과도류형，분별위“파배상류형”화“초대기탄류형”，인차，대상승단화하강단분별건립료류형도。분별획득료와식라선관연관장화연라선관횡절면원주방향적벽면온도분포특성。벽면온도연관장정축점강저적추세；연횡절면원주방향，최외측벽온최저，최내측벽온최고，량측온도거중。
This paper presented an experimental investigation on flow boiling patterns and wall temperatures of R134a in horizontal helically-coiled pipe. The experiments were carried out at saturation temperature from 5 to 15℃, with the refrigerant mass flux varying from 50 to 500 kg/(m2?s), heat flux varying from 5 to 25 kW/m2, and the vapor quality ranging from 0.01 to 0.9. Through visualization experiment, it can be found that the flow patterns in the rising and declining sections are different under the same conditions. The transition flow patterns before the annular flow are obviously different, which are “wave annular flow” and “super slug flow”, so two different flow pattern figures were proposed for the rising and declining sections, respectively. The wall temperature distribution during flow boiling was experimentally determined. The results show that the wall temperature gradually decreased along the tube; along the cross-section circumference, the outside temperature of the cross section is the lowest, and the inside temperature is the highest.