中文摘要：

利用TSI-1268W热膜探头对内径为35mm的水平管内气液两相泡状流的壁面切应力进行了直接测量，得到了进口段不同截面上沿周向不同位置处的壁面切应力数据，通过分析实验段进口段的壁面切应力沿管长的变化来确定进口段的长度．结果表明，液相中加入气泡后增加了壁面切应力数据的离散程度．在实验参数范围内，测量的壁面切应力进口段的长度在52D～65D之间，并且壁面切应力进口段随着液流Reynolds数和截面含气率的增大而增大．液相中加入气泡后在不同的测量角度壁面切应力的变化呈现不同的特征．

英文摘要：

Experiments were carried out to measure the wall shear stress （WSS） of air-water bubbly flow in the entrance region in a horizontal tube I. D. 35 mm with TSI 1268W hot-film probes, and the wall shear stress data at different points in different sections were obtained and used to determine the development length. It was found that the discrete degree of WSS data increased due to introducing bubbles into the liquid. The development length was 52D--65D and increased with increasing liquid Reynolds number and void fraction. Due to the asymmetric distribution of bubbles in the horizontal tube, introducing bubbles made the wall shear stress change differently at different measuring points.