助走域における流動特性

垂直管内気液二相流に関する研究 (第1報)

抄録

This paper presents an experimental investigation of an axial developing process of bubble and slug flow patterns for airwater mixtures upward flowing. The experiments were carried out in a transparent aclylic plastic pipe of 39.6 mm diameter and 5.66 m length. To investigate the effect of inlet conditions on the flow characteristics four air injectors were used and void properties such as bubble transit frequency, void fraction, bubble transit length and bubble velocity were measured by electrical resistivity probe technique up to the axial position of 100 pipe diameters from the air injector. Also axial pressure distributions were measured.
The results are as follows: It is difficult to examine the entrance region by the pressure gradient in bubble and slug flow patterns because the static pressure changes monotonously. In the flow conditions of transition from bubble to slug flow patterns the flow properties of entrance region depend on inlet conditions. In the case of slug formation at just near air injectors the developing process is independent of inlet conditions and the flows develop at the axial position of 80 to 100 pipe diameters.