The steam jet pump (SJP) is mechanically very simple device; however, the physics of the flow through it is very complex. In this paper, the mass, momentum, and energy transfers between the two phases in SJP have been studied by employing experimental, computational, and flow visualization techniques. The experimental, CFD, and visual results were obtained at different operating conditions and for three different lengths of the mixing section. The study is very important in developing understanding of the transport phenomena occurring within the mixing section of SJP under different operating and geometrical parameters. The comparison of experimental and numerical results also validates the direct-contact condensation model used for CFD analysis. © 2017 by Begell House, Inc.