The effect of five different bottom gas blowing scheme on flow characteristics of liquid steel and inclusions removing from steel in tundish has been studied by using 1: 3 water model-testing for a 40 t tundish to measure the flow field of liquid in tundish for 6 strands billet casting. Results show that the residence time of liquid in tundish is prolonged by gas blowing at injection flow area to decrease the turbulence intensity

while gas blowing at injection flow area is available to break the bubbles to form disperse small bubbles

promote inclusions floating up and get best inclusions removing effect ； the gas blowing at area between near flow nozzle and med. flow nozzle is available to improve flow characteristics

at this situation the flow condition of liquid is best but the inclusion removal at near nozzle area is lower ； and the gas blowing at area between med. flow nozzle and far flow nozzle is not an idea location to effectively improve the flow field.