Abstract: This paper develops a three-dimensional model of the closed engineroom heat exchanger by using the Pro/E software. Based on the obtained numerical model，the shell-side turbulent flow and heat transfer characteristics of the examined heat exchanger is analyzed with the aid of the Computational Fluid Dynamics（CFD）software Fluent. Particularly，by taking the shell-side pressure drop，the total heat transfer rate，and the flow rate as three comprehensive indicators，the field of velocity，temperature，and pressure of the heat exchanger under different baffle nick heights and numbers are investigated. The results show that as the segmental baffle number increases，the pressure drop at the shell-side rises and the outlet temperature drops；meanwhile，when the baffle nick height increases，the pressure drop decreases and the outlet temperature increases.