For annular flow in a horizontal pipe

the gravity force resulted in an asymmetric distribution of the liquid film flowing along the pipe wall. Using five parallel-wire conductance probes

time records were collected on local liquid film thickness at five circumferential positions. The liquid upward transport mechanism is very important for predicting the circumferential liquid film thickness distribution in horizontal gas-liquid annular flow. Taking into consideration the pumping action of disturbance waves

the induced secondary flow in the gas flow

entrainment and deposition of droplets a theoretical model of circumferential distribution of liquid film thickness was developed with stress balance and order analysis method. The filmthickness distribution obtained from the model accorded with the experimental data very well.