Open Access

ARTICLE

LAMINAR FLOW HEAT TRANSFER IN HELICAL OVAL-TWISTED TUBE FOR HEAT EXCHANGER APPLICATIONS

Scott Wahlquist^a, Amir Ali^a,b,*, Su-Jong Yoon^c, Piyush Sabharwall^c

a Idaho State University, Pocatello, Idaho, 83209, USA
b Center for Advanced Energy Studies (CAES), Idaho Falls, Idaho, 83401, USA
c Idaho National Laboratory, Idaho Falls, Idaho, 83415, USA
* Corresponding Author Email: amirali@isu.edu

Frontiers in Heat and Mass Transfer 2022, 18, 1-8. https://doi.org/10.5098/hmt.18.35

Abstract

The heat transfer performance of a novel tube configuration that combines the swirling velocity induced by oval-twisting and secondary flow generated by a helical geometrical flow path is presented. The Nusselt number (Nu) and friction factor (f) are compared for the laminar flow regime (Re = 250- 2000) under isothermal wall conditions. Under the same flow and boundary conditions, the oval-twisted helical tube increased the Nu and slightly increased the f over the circular helical tube. The best performance with the highest Nuand lowest f occurs at the coil curvature ratio (d_h/D) of 0.17. The quantified enhancement performance factor (h) shows a 46 - 56% increase for the oval-twisted helical tube over the circular helical tube with d_h/D = 0.17. Correlations for the Nu and f are developed and agreed with the numerical results: ± 6% and ± 5% for the Nu and f, respectively.

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Keywords

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