R134a臣卧式螺旋管内流动沸腾换热特性实验研究

对R134a在水平直管和螺旋管内的沸腾换热特性进行了实验研究.在三个不同的蒸发温度(5℃、10℃和20℃),工质R134a的质量流量范围为100～400kg/(m~2·s)和干度范围为0.1～0.8的条件下,实验得到了R134a在水平直管和螺旋管内的沸腾换热系数随其质量流量和干度的变化关系,将水平直管和螺旋管内的沸腾换热特性数据进行了比较,结果显示,在实验条件下,卧式螺旋管的传热系数比直管的平均增加13.7%.

Experimental Investigation on Flow Boiling Heat Transfer of R134a in Helically-coiled Tube

An experiment was conducted to investigate the flow boiling heat transfer of R134a in a horizontal straight tube and a helically-coiled tube at three saturation temperatures (5℃, 10℃ and 20℃) with the refrigerant mass flux of 100-400 kg/(m~2·s), the heat flux of 5-20 kW/m~2, and the vapor quality of 0.1-0.8. The influence of vapor quality, heat flux, saturation temperature, and mass flux of R134a on the boiling heat transfer coefficient in the horizontal straight tube and the helically-coiled tube was obtained. The comparison between our experimental results and the data available in literature shows that the boiling heat transfer coefficients of R134a in the helically-coiled tube were 13.7% greater in average than those in the horizontal straight tube under the experimental conditions.