Optical fiber sensor

as a new technique in the field of fiber optics

has received more and more attention in the measurement of local parameters in two-phase flow.The mathematical principle of the local instantaneous bubble velocity vector measurement using four-sensor probe was deduced by assuming a plane of symmetry of bubbles normal to the motion

and a new mathematical model was presented.An investigation was conducted for obtaining bubble velocity vector in two-phase flow by using a self-made four-sensor optical fiber probe.By comparing the superficial gas velocity obtained from the new probe method with that measured by flow meter

it was found that average deviation was about 9%

indicating a relatively high metrical precision of the new probe method.A further study indicated that local void fraction and interfacial area concentration(IAC)showed a wall peak or a core peak distribution in the radial direction under different flow conditions.