Experimental and numerical investigation of heat transfer in a concentric heat exchanger

In this study, the effect of four different types of turbulators placed inside the pipe entrance in a concentric (nested) heat exchanger on heat transfer and pressure drop has been investigated experimentally and numerically. For this purpose, an experimental system of heat exchanger was established in which air passed through the inner tube as hot fluid whereas water passed through the outer pipe as cold fluid. Some experiments have been conducted under the same and opposite directional parallel flow conditions in order to investigate the effect of turbulators that are produced as unperforated and perforated in different positions on heat transfer. Exergy analysis of system has been made.The basic governing equations have been solved under steady-state, three-dimensional and turbulent flow conditions using ANSYS Fluent code program which is a computer program based on finite volume method in numerical study. Different levels of air flow ( 7, 8, 9, 10, 11 and 12 m3/h ) have been obtained from the results of numerical analysis. Also, temperature, velocity and pressure distributions have been obtained as a result of the numerical analysis.Experimental and numerical results have been compared and found to be in harmony with each other. When the research data was analysed, it became clear that maximum heat transfer happens in the inner, outer wing and body perforated turbulators.