A new tundish is designed with the aim to produce a swirling flow in a tundish SEN by an economical way of using the steel flow potential as the required power. This design is easily obtained by adding a cylindrical part of the tundish onto a traditional tundish. The results show that a swirling flow in the SEN of the new tundish is successfully obtained, also, that the tangential velocity in the SEN can reach around 1.6ms-1. The installation of weirs in the cylindrical tundish can contribute to stabilize the steel flow at the top of the tundish. However, this reduces the swirling flow intensity in the SEN around 30%. In addition, the possibility of slag entrainment at the top of the tundish is analyzed. The calculated Weber Number is around 5.0 for no weir case and 2.8 for the weir case, which means that the risk of slag entrainment is small. A high value of shear stress is found on the SEN wall due to the swirling flow in SEN. A further investigation shows that a smooth transition of SEN inlet can reduce the maximum shear stress level in the SEN, without decreasing the swirling flow intensity.