Abstract: Under certain specific conditions, a zone of recirculation may be formed in confined jet. Confined jets are often used for tubular reactors, evolution of recirculation will creat backmixing of fluids disturbing reactor performance. The authors of this paper conducted experiments involving recirculation phenomena in confined jets. Factors affecting the occurence of recirculation were studied. The initial and ending points of recirculation were identified. Based on the model for free turbulent round jets, a correlation formula was derived for estimating the initial point of recirculation in confined jets.