Abstract: The flow pattern of liquid phase in the first cell of anaerobic baffled reactor(ABR) was studied in association with laser particle image velocimetry(PIV) under the combined conditions of different inlet flow rates and suspension heights of inlet pipe of the ABR.Flow field data at key section in downward flow area and upward flow area of the reactor were obtained, and the curves of velocity of liquid phase and vorticity intensity vs. suspension height were acquired. Meanwhile, characteristics of relevant flow fields were obtained, including streamline pattern and vorticity field. Results revealed that reasonable suspension height of water inlet pipe was important for the first cell of ABR, for it could ensure good flow pattern, uniform distribution of ABR vortex area, effective prevention of local channel flow and dead zone at liquid phase and stable operation of ABR. According to the experimental results, we suggest the range of suspension height of inlet pipe between 230-530 mm when flow rate is in the range of0.018-0.270 m³/h , and 530 mm when flow rate is in the range of0.558-0.846 m³/h.

Key words: anaerobic baffled reactor, flow pattern of fluid phase, particle image velocimetry, layout of vertical inlet pipe, suspension height