Experimental and Numerical Investigation of the Pressure Drop and Heat Transfer Coefficient in Corrugated Tubes

Abstract

Single-structured tubes (SSTs) and cross-structured tubes (CSTs) with helix-based structures are investigated with respect to their heat transfer properties and pressure drop based on the measurements of a non-isothermal gas flow inside the tubes. The examined Reynolds number range corresponds to relevant shell-andtube heat exchanger applications. After a detailed description of the measuring methods used, the test facilities and their validation-appropriate wall geometries with a high potential for heat transfer improvements are discussed. The experimental results show that the Nusselt number can be improved by varying the structure depth and angle of the helix, which can also influence the pressure drop in the tube. Numerical simulations demonstrate that the tangential velocity in the SSTs strongly varies with the structure angle, while the flow inside the CSTs only rotates locally.

Experimental and Numerical Investigation of the Heat Transfer of Honeycomb-Structured Tubes

“…While concave structuring brings significant heat transfer advantages, this does not occur with convex structuring. This behaviour corresponds with the results of [11,12] and confirms the strong dependence of heat transfer on the structuring.…”

“…Further numerical studies [9,10] have shown that an increase in heat transfer performance is associated with structuring. Further possibilities are the use of spirally structured [11] or corrugated [12] tubes. In both cases, the heat transfer coefficient of the structured surface increases significantly compared to a smooth surface.…”

Enhanced heat transfer in tubes based on vascular heat exchangers in fish: Experimental investigation

“…However, single spirally corrugated tubes showed 1.66 times higher Nu value regardless of Re. Moreover, increase in pressure drop, as concluded in [23], depends on the corrugation angle in single spirally corrugated tubes while in cross-spirally corrugated tubes pressure drop rose significantly regardless of the corrugation angle. Pethkool et al, [17] reported up to 300 % higher Nu values for helically corrugated tubes with the increase in friction factor by 1.93 when compared with a smooth tube.…”

“…The Authors also concluded that the combination of the two heat transfer techniques is more effective than each of them separately. Mac Nelly et al, [23] investigated single spirally corrugated and cross spirally corrugated tubes using laboratory air in the Re range 4000 to 20000 with a Prandlt number (Pr) lower than 1. The Authors concluded that Nusselt number (Nu) increases up to 1.88 times in crossspirally corrugated tubes with increasing Re when compared to a straight one.…”

Experimentelle Untersuchung der Tropfenkondensation am chemisch modifizierten Edelstahl‐Drallrohr

“…5a). Auch hinsichtlich des steigenden Druckverlustes beim Drallrohr gilt dies als ein vielversprechendes Ergebnis 16.…”