Effect of Spacing Between Baffles on the Dynamic and Thermal Behavior of Water in a Shell-and-Tube Heat Exchanger Ahmed Youcef 1* , Rachid Saim 2 1 Research Unit for Renewable Energies in the Saharan Region (URERMS) Renewable Energy Development Center (CDER), Adrar 01000, Algeria 2 Energetic and Applied Thermal Laboratory (E.T.A.P) Faculty of Technology, Abou Bekr Belkaid University, Tlemcen BP 230- 13000, Algeria Corresponding Author Email: a_youcef83@urerms.dz https://doi.org/10.18280/rcma.320307 ABSTRACT Received: 12 May 2022 Accepted: 19 June 2022 A numerical simulation of a turbulent flow of water in three shell and tube heat exchangers equipped with 6, 8, 10 segmental baffles as the working fluid at Reynolds numbers ranging from 24327, 33356, 42569 are performed. The conservation equations of mass, momentum and energy are solved by the finite volume method based on the SIMPLE algorithm for coupling velocity-pressure, the mathematical model k-ε within the Fluent software is used in the different cases presented. The temperature, the velocity, the friction factor, the heat transfer coefficient, the pressure drop in the shell, the total heat transfer rate between the tubes and the fluid, the overall performance factor are studied for the three spacing between baffles. This work contributes largely to the understanding of turbulent flows and also shows the effect of the baffles number on the heat transfer in the heat exchangers. The velocity of flow in the shell increases by 1.49% and 1.62% and 1.73% of the reference velocity. The results show an increase in the outlet temperature, heat transfer coefficient 1.09% and 1.28%, pressure drop 1.7% and 2.82%, the total heat transfer rate 1.08% and 1.18% because of the increase in number of baffles. The results obtained in this study are in good agreement and correspond to the results given by the literature. Keywords: baffle, shell and tube heat exchanger, CFD 1. INTRODUCTION The tubular heat exchangers contain a number of tubes packed in a shell with their axes parallel to that of the shell. The process of heat transfer takes place as a fluid flow into the tubes, while the other fluid flows to the side of the shell through the bundles of tubes. Baffles are used to control the distribution of the shell side flow as well as the improvement of heat transfer. In recent years, shell and tube heat exchangers are widely used in many fields of engineering such as chemical engineering processes, power generation, petroleum refining, refrigeration, air conditioning, the food industry [1]. The shell- and-tube heat exchangers are relatively simple to manufacture, and offer versatile application in comparison with other types of heat exchangers [2], it is reported that more than 30% of the heat exchangers used are of the type shell tube [3]. Among the works carried for this type of heat exchanger, Gao et al. [4]. the authors carried experimental studies on discontinuous helical baffles at different angles 8°, 12°, 20°, 30° and 40° and reported that the performance of the helix angle 40° is the best among those tested. You et al. [5]. developed numerical model a two-section segmental baffle over a Reynolds range from 6813 to 22326 for the shell side, the results of the simulations prove that the flow regime is different and has a better overall thermal performance than the heat exchanger with unique segmental baffles. Wang et al. [6]. carried experimental research on heat exchangers with segmental baffles and the two-section, the model with two sections reported was 20 to 30% more efficient than that of the segmental baffle under the same operating conditions. Ma’arof et al. [7]. Investigates the effects of diverse designs default, angled, perforated and coated for the rate of heat transfer in heat exchanger, the coating on the fins was decreasing the temperature at a much higher margin at all fan speeds. Youcef et al. [8] studied numerically the performance of new type baffles and show that the wing shape serves to promote a complete mixing of the fluid. Youcef et al. [9, 10] in order to understand the effect of the use of baffles in the heat exchanger, a comparative study was presented and show that the heat transfer coefficient and the pressure drop increase by 1, 86% and 21.67%. Youcef et al. [11] studied three baffles inclination angles 10°, 20°, 40°. The results show that the heat transfer coefficient and the pressure drop decreased by 0.983% and 0.992% respectively with increasing inclination. Cucumo et al. [12], show that decrease in pressure drop with increasing helix angle. Dipankar et al. [13], the heat transfer coefficient increases with the increase of velocity. Reducing the baffles spacing has a petal effect on the heat transfer because the increase in the baffles number increases the residence time and the fluid particle trajectory length in the shell therefore a higher heat transfer between the tubes and the fluid consequently a considerable increase in the thermal performance of the heat exchanger, the present study examines numerically in 3D using the FLUENT code, the thermo- Revue des Composites et des Matériaux Avancés-Journal of Composite and Advanced Materials Vol. 32, No. 3, June, 2022, pp. 157-163 Journal homepage: http://iieta.org/journals/rcma 157