Investigation of noncircular orifice supporting baffle longitudinal flow heat exchangers

Owing to the disadvantages of the segmental baffle heat exchanger (SBHE–STHE), a novel type of supporting baffle longitudinal flow heat exchanger is proposed and numerically studied. This equipment includes hexagonal cinquefoil, regular quadrangular, trefoil fillet, and reticulated orifice baffle heat exchangers. The flow and heat transfer performance of the four noncircular orifice supporting baffle longitudinal flow heat exchangers are investigated. Combined sections were fabricated, and local performance characteristics of temperature, pressure, and flow field contours were examined. A composite dimensionless index based on SBHE–STHE is proposed to quickly estimate the comprehensive characteristics of the four supporting baffle longitudinal flow heat exchangers. Results show that the noncircular orifices within the supporting baffle induce jet flow and fluid disturbance. Consequently, periodic pulsating vortices among adjacent supporting baffles are generated, explaining the heat transfer enhancement mechanism. The heat transfer capability of the reticulated orifice baffle heat exchanger is higher than that of the other three orifice baffle schemes and similar to that of the SBHE–STHE. All the comprehensive performance indices of the four noncircular orifice schemes are higher than those of the SBHE–STHE.