ARTICLE:

• NUMERICAL INVESTIGATION OF THE EFFECT OF BAFFLE ORIENTATION AND BAFFLE CUT ON HEAT TRANSFER AND PRESSURE DROP OF A SHELL AND TUBE HEAT EXCHANGER  download article

Wolfgang Heidemann
Institute of Thermodynamics and Thermal Engineering, University of Stuttgart, Germany

Koorosh Mohammadi
Institute of Thermodynamics and Thermal Engineering, University of Stuttgart, Germany

Hans Muller-Steinhagen
Institute of Thermodynamics and Thermal Engineering, University of Stuttgart; and Institute of Technical Thermodynamics, German Aerospace Centre, Stuttgart, Germany

ABSTRACT

The commercial CFD code FLUENT is used to obtain the effect of baffle orientation and baffle cut as well as viscosity of the working fluid on the heat transfer and pressure drop of a shell and tube heat exchanger in the domain of laminar and turbulent flow. The shell and tube heat exchanger considered follows the TEMA standards and consists of 660 plane tubes with fixed outside diameter which are arranged in a triangular layout. Different baffle orientations as well as different baffle cuts are considered. No leakage flows are taken into account. For the numerical investigations the heat exchanger is subdivided into eight different flow sections such as the inlet zone, six intermediate flow sections located between adjacent baffles and the outlet zone. In order to determine the effect of viscosity on heat transfer and pressure drop, simulations are performed for three different working fluids in the range of 0.7 to 206 for the Prandtl number. For each baffle orientation, baffle cut and working fluid, simulations are performed using different flow velocities at the inlet nozzle. Heat transfer and pressure drop are reported as overall Nusselt number (Nu) and Karman number (Nk), respectively, which are defined similar to VDI Wärmeatlas (2002), section Gh. Results for all geometrical variations show that Nk is proportional to Re² and Nu is proportional to Re^{0.6−0. 8}. Simulation results for the inlet region show that the horizontal baffle orientation produces up to 20% higher pressure drop than the pressure drop in vertical baffle orientation. The results also show that the Nusselt number for horizontal baffle orientation is approximately 15% to 52% higher than the Nusselt number for vertical orientation.

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