水平管气液两相泡状流入口段流速场的实验研究

Velocity Distribution in the Entry Region of a Horizontal Air-Water Bubbly Flow

用热膜测速技术对水平管气液两相泡状流入口段中的液流速度及局部含气率分布进行了研究.实验时液流折算速度为3 5～4 0m/s,气流折算速度为0～0 44m/s.结果表明,在入口段中液流速度随液流折算速度的增加而增加,随气流折算速度的增加而分布更不均匀.含气率随气流折算速度的增加而增加,随液流折算速度增加分布趋于均匀.在本实验范围内,当实验测试段长度与管径比L/D大于109后,液流速度和局部含气率的分布随L/D的变化已不很明显,可认为达到充分发展区域.

An experimental study of the velocity distribution in the entry region of a horizontal air-water bubbly flow was presented, where hot-film anemometry technique was applied to the measurements of local liquid velocities and void fractions, and the superficial liquid velocities were taken as 3.5-4.0 m/s, and the superficial air velocities as 0-0.44 m/s. The experimental result indicates that the liquid velocity near the region increases with the increase of the superficial one, and distributes more asymmetrically. The local void fraction increases with accelerated gas flow and the distribution tends more symmetrical. In the experimental region, where the ratio of the length to diameter L/D is larger than 109, the liquid velocity and void fraction profiles doesn't vary with L/D obviously, which means that a fully developed state is achieved.