n.回流；逆流
This would create an air gap to eliminate any possible backflow. 这将产生一个气隙以消除任何可能的回流。
In the event of negative supply pressure such contaminated fluids will not backflow to the supply source by backsiphonage. 万一存在这种污染流体的反压力，则要避免由于反虹吸而回流到供应水源中。
Furthermore, the main reason of the axial backmixing of the liquid is the liquid backflow which induced by the reverse flow of the bubbles. 计算结果表明，在逆流操作中液相轴向返混主要是由于气泡的逆向运动诱导产生的液相回流引起的。
