1 ST INTERNATIONAL CONFERENCE in MECHANICAL ENGINEERING RESEARCH ( ICMER ) 2011 216 A Numerical Study of Forced Convection Heat Transfer for Staggered Tube Banks in Cross-Flow T. A. Tahseen 1 , M. Ishak 1,2 and M. M. Rahman 1,2 1 Faculty of Mechanical Engineering, University Malaysia Pahang 26600 Pekan, Pahang, Malaysia Phone : +609-424-2246 ; Fax : +609-424-2202 Email: tahseen444@gmail.com; mahadzir@ump.edu.my; mustafizur@ump.edu.my 2 Automotive Engineering Centre, Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia. Abstract: This paper presents the numerical study on the two-dimensional forced convection heat transfer for staggered tube banks in cross flow under incompressible, steady-state conditions. This system is solved on the body fitted coordinates (BFC) using the finite difference method (FDM) for the flow over a bundle of cylindrical tubes. The constant heat flux is imposed on the surface of the tubes as the thermal boundary condition. The type of the arrangement is considered a staggered of tubes. The longitudinal pitch to tube diameter ratios (S T /D) of 1.25, 1.5 and 2 are also considered. Reynolds numbers are varied from 25 to 250 and Prandtl number is taken as 0.71. Velocity field vectors and temperature contours, local and average Nusselt numbers were analysed in this paper. It can be seen that the predicted results are good agreements with previous experimental and numerical results. The obtained results show that the heat transfer rate increases with decreases of the step to the longitudinal tube diameter. The local heat transfer strongly depends on the Reynolds number. It tends to obtain the highest values at the surface opposite to the direction of flow. The heat transfer rate is insignificant in the areas of recycling. Keywords: Forced convection, cylindrical tube, staggered arrangement, body fitted coordinates, finite different method. 1. Introduction The flow of fluids and heat transfer in tube banks represents an idealization of many industrially important processes. Tube bundles are widely employed in cross-flow heat exchangers, the design is still based on empirical correlations of heat transfer and pressure drop. Heat exchangers with tube banks in cross-flow are of great practical interest in many thermal and chemical engineering processes (Incropera and Dewitt, 1996; Buyruk, 2002; Mandhani et al. 2002; Liang and Papadakis, 2007; Kaptan et al., 2008). A two dimensions numerical study pressure drop, heat transfer and incompressible laminar flow for staggered tube arrays in cross- flow (Yuan et al., 1998; Rahmani et al., 2005; Khan et al., 2006; Marchi and Hobmeir, 2007). The low Reynolds number and Prandtl number equal to 0.71 are considered in general (Chang et al., 1989; Wang and Georgiadis, 1996). An experimental study was carried out to investigate heat transfer and flow characteristics from one tube within a staggered tube bundle and within a row of similar tubes. Variation of a local Nusselt number and local pressure coefficients were shown with different blockages and Reynolds numbers (Buyruk et al., 1998; Buyruk, 1999; Matos et al., 2001, 2004). The experimental and numerical study pressure drop and heat transfer