@Article{hmt.18.35,
AUTHOR = {Scott Wahlquist, Amir Ali, Su-Jong Yoon, Piyush Sabharwall},
TITLE = {LAMINAR FLOW HEAT TRANSFER IN HELICAL OVAL-TWISTED  TUBE FOR HEAT EXCHANGER APPLICATIONS},
JOURNAL = {Frontiers in Heat and Mass Transfer},
VOLUME = {18},
YEAR = {2022},
NUMBER = {1},
PAGES = {1--8},
URL = {http://www.techscience.com/fhmt/v18n1/52466},
ISSN = {2151-8629},
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 (<i>Nu</i>) and friction factor (<i>f</i>) are compared for the laminar flow regime (<i>Re</i> = 250-
2000) under isothermal wall conditions. Under the same flow and boundary conditions, the oval-twisted helical tube increased the <i>Nu</i> and slightly 
increased the <i>f</i> over the circular helical tube. The best performance with the highest <i>Nu</i>and lowest <i>f</i> occurs at the coil curvature ratio (<i>d<sub>h</sub>/D</i>) 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 
<i>d<sub>h</sub>/D</i> = 0.17. Correlations for the <i>Nu</i> and <i>f</i> are developed and agreed with the numerical results: ± 6% and ± 5% for the <i>Nu</i> and <i>f</i>, respectively.},
DOI = {10.5098/hmt.18.35}
}