A new configuration of bend tubes for compound optimization of heat and fluid flow

• Pressure drop and entropy generation is investigated numerically.
• It is shown that there is an optimal design of partially curved tubes.
• Pressure drop and entropy generation are minimized.
• Partially curved tubes are superior than customary fully curved tubes.

Curved pipes constitute essential components in engineering systems such as heat exchangers, and process pipelines. In curved pipes with 180° bends, the excess pressure drop, and the excess entropy generation (through heat and fluid flow) bring forth serious penalties. To overcome these difficulties a new partially curved pipe will be examined in this paper. It consists of three straight pipe segments connected with two 90° bends. The pressure drop and entropy generation are determined numerically for several configurations of ‘partially curved’ pipes when the fluid flow is laminar, viscous and incompressible. It is shown that the new curved pipe is advantageous because the pressure drop and entropy generation are considerably reduced when implementing the optimum layout, compared to the standard case of a fully curved section with 180° bend. As an added value, it is shown that the new optimum partially curved pipes are almost independent of Reynolds and Prandtl numbers.