{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,22]],"date-time":"2025-10-22T18:13:56Z","timestamp":1761156836332,"version":"build-2065373602"},"reference-count":30,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2020,2,5]],"date-time":"2020-02-05T00:00:00Z","timestamp":1580860800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51866007"],"award-info":[{"award-number":["51866007"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Gansu Provincial Natural Science Foundation","award":["17JR5RA092"],"award-info":[{"award-number":["17JR5RA092"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>The generation of longitudinal vortices is an effective method for promoting thermal performance with a relative low-pressure penalty in heat exchangers. The winglet pair can generate symmetrical longitudinal vortices on the cross-section of the channel. The heat transfer and pressure-loss characteristics of a pair of winglet vortex generators with different transverse pitches are numerically studied in this paper. The winglet pair arranged in a common flow up configuration generates a pair of symmetrical longitudinal main vortices with counter-rotating directions. The symmetrical flow structure induces fluid to flow from the bottom towards the top of the channel in the common flow region between the longitudinal vortices. The flow symmetry of the longitudinal vortices and the heat transfer performance are strongly affected by the transverse pitch of the winglet pair owing to the interaction between the longitudinal vortices. The optimal transverse pitch of the studied winglet pair with the best thermal performance is reported. The increments in the vortex intensity and the Nusselt number for the optimal pitch are increased by up to 21.4% and 29.2%, respectively.<\/jats:p>","DOI":"10.3390\/sym12020247","type":"journal-article","created":{"date-parts":[[2020,2,7]],"date-time":"2020-02-07T03:13:27Z","timestamp":1581045207000},"page":"247","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Flow Symmetry and Heat Transfer Characteristics of Winglet Vortex Generators Arranged in Common Flow up Configuration"],"prefix":"10.3390","volume":"12","author":[{"given":"Kewei","family":"Song","sequence":"first","affiliation":[{"name":"School of Mechanical Engineering, Key Laboratory of Railway Vehicle Thermal Engineering of Ministry of Education of China, Lanzhou Jiaotong University, Lanzhou 730070, China"}]},{"given":"Lu","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Key Laboratory of Railway Vehicle Thermal Engineering of Ministry of Education of China, Lanzhou Jiaotong University, Lanzhou 730070, China"}]},{"given":"Yajun","family":"Hu","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Key Laboratory of Railway Vehicle Thermal Engineering of Ministry of Education of China, Lanzhou Jiaotong University, Lanzhou 730070, China"}]},{"given":"Qi","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Key Laboratory of Railway Vehicle Thermal Engineering of Ministry of Education of China, Lanzhou Jiaotong University, Lanzhou 730070, China"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,5]]},"reference":[{"key":"ref_1","unstructured":"Tao, W.Q. (2001). Numerical Heat Transfer, Xi\u2019an Jiaotong University Press. [2nd ed.]."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1480","DOI":"10.1016\/j.ijheatmasstransfer.2004.10.018","article-title":"Impact of leading edge delta-wing vortex generators on the thermal performance of a flat tube, louvered-fin compact heat exchanger","volume":"48","author":"Joardar","year":"2005","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/j.ijrefrig.2007.04.011","article-title":"Heat transfer enhancement by winglet-type vortex generator arrays in compact plain-fin-and-tube heat exchangers","volume":"31","author":"Joardar","year":"2008","journal-title":"Int. J. Refrig."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1156","DOI":"10.1115\/1.2740308","article-title":"A Numerical Study of Flow and Heat Transfer Enhancement Using an Array of Delta-Winglet Vortex Generators in a Fin-and-Tube Heat Exchanger","volume":"129","author":"Joardar","year":"2007","journal-title":"J. Heat Transf."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"295","DOI":"10.1016\/0894-1777(95)00066-U","article-title":"Heat transfer surface enhancement through the use of longitudinal vortices: A review of recent progress","volume":"11","author":"Jacobi","year":"1995","journal-title":"Exp. Therm. Fluid Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"588","DOI":"10.1115\/1.2910910","article-title":"Generation of longitudinal streamwise vortices\u2014A device for improving heat exchanger design","volume":"116","author":"Biswas","year":"1994","journal-title":"Heat Transf."},{"key":"ref_7","first-page":"3","article-title":"Vortices and heat transfer","volume":"77","author":"Fiebig","year":"1977","journal-title":"J. Appl. Math. Mech."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1615\/JEnhHeatTransf.v2.i1-2.60","article-title":"Vortex generators for compact heat exchangers","volume":"2","author":"Fiebig","year":"1995","journal-title":"Enhanc. Heat Transf."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2661","DOI":"10.1016\/j.ijheatmasstransfer.2010.12.040","article-title":"Numerical study of the fin efficiency and a modified fin efficiency formula for flat tube bank fin heat exchanger","volume":"54","author":"Song","year":"2011","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"064502","DOI":"10.1115\/1.2897339","article-title":"Tube transverse pitch effect on heat\/mass transfer characteristics of flat tube bank fin mounted with vortex generators","volume":"130","author":"Liu","year":"2008","journal-title":"J. Heat Transf."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"496","DOI":"10.1504\/PCFD.2008.021327","article-title":"Relationship between heat transfer intensity and absolute vorticity flux intensity in flat tube bank fin channels with Vortex Generators","volume":"8","author":"Song","year":"2008","journal-title":"Prog. Comput. Fluid Dyn."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3683","DOI":"10.1016\/j.ijheatmasstransfer.2007.03.031","article-title":"Numerical study on laminar convection heat transfer in a channel with longitudinal vortex generator part B: Parametric study of major influences factors","volume":"51","author":"Wu","year":"2008","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3023","DOI":"10.1016\/j.ijheatmasstransfer.2010.03.026","article-title":"Experimental study of rectangular channel with modified rectangular longitudinal vortex generators","volume":"53","author":"Min","year":"2010","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1016\/j.icheatmasstransfer.2008.10.018","article-title":"Numerical study of fluid flow and heat transfer in a flat-plate channel with longitudinal vortex generators by applying field synergy principle analysis","volume":"36","author":"Tian","year":"2009","journal-title":"Int. Commun. Heat Mass Transf."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2895","DOI":"10.1016\/j.enconman.2011.03.002","article-title":"Impact of delta winglet vortex generators on the performance of a novel fin-tube surface with two rows of tubes in different diameters","volume":"52","author":"Wu","year":"2011","journal-title":"Energy Convers. Manag."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"298","DOI":"10.1016\/j.applthermaleng.2018.01.012","article-title":"Experimental and numerical study and comparison of performance for wavy fin and a plain fin with radiantly arranged winglets around each tube in fin and-tube heat exchangers","volume":"133","author":"Li","year":"2018","journal-title":"Appl. Therm. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/j.ijheatmasstransfer.2018.04.071","article-title":"Effect of winglet location on performance of fin-tube heat exchangers with inline tube arrangement","volume":"125","author":"Naik","year":"2018","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.expthermflusci.2016.11.002","article-title":"Effect of geometric size of curved delta winglet vortex generators and tube pitch on heat transfer characteristics of fin-tube heat exchanger","volume":"82","author":"Song","year":"2017","journal-title":"Exp. Therm. Fluid Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1016\/j.ijthermalsci.2018.11.002","article-title":"Heat transfer characteristics of concave and convex curved vortex generators in the channel of plate heat exchanger under laminar flow","volume":"137","author":"Song","year":"2019","journal-title":"Int. J. Therm. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1016\/j.ijthermalsci.2018.11.009","article-title":"Effects of curved vortex generators on the air-side performance of fin-and-tube heat exchangers","volume":"136","author":"Lu","year":"2019","journal-title":"Int. J. Therm. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/j.ijrefrig.2018.10.021","article-title":"Numerical study of thermal and flow characteristics for a fin-and-tube heat exchanger with arc winglet type vortex generators","volume":"98","author":"Han","year":"2019","journal-title":"Int. J. Refrig."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1054","DOI":"10.1016\/j.ijheatmasstransfer.2018.07.148","article-title":"Analysis on heat transfer and pressure drop of fin-and-oval-tube heat exchangers with tear-drop delta vortex generators","volume":"127","author":"Lu","year":"2018","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1016\/j.applthermaleng.2017.01.106","article-title":"Effect of winglet location on heat transfer of a fin-and-tube heat exchanger","volume":"116","author":"Sarangi","year":"2017","journal-title":"Appl. Therm. Eng."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"041902","DOI":"10.1115\/1.4023037","article-title":"The effectiveness of secondary flow produced by vortex generators mounted on both surfaces of the fin to enhance heat transfer in a flat tube bank fin heat exchanger","volume":"135","author":"Song","year":"2013","journal-title":"ASME J. Heat Transf."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1016\/j.ijheatmasstransfer.2015.10.001","article-title":"Interaction of counter rotating longitudinal vortices and the effect on fluid flow and heat transfer","volume":"93","author":"Song","year":"2016","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1064","DOI":"10.1016\/j.applthermaleng.2016.05.022","article-title":"Quantitative relationship between secondary flow intensity and heat transfer intensity in flat-tube-and-fin air heat exchanger with vortex generators","volume":"103","author":"Song","year":"2016","journal-title":"Appl. Therm. Eng."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1016\/j.ijthermalsci.2016.06.011","article-title":"Effects of longitudinal vortex interaction on periodically developed flow and heat transfer of fin-and-tube heat exchanger","volume":"109","author":"Song","year":"2016","journal-title":"Int. J. Therm. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1016\/j.ijthermalsci.2018.06.011","article-title":"The optimal arrangement of vortex generators for best heat transfer enhancement in flat-tube-fin heat exchanger","volume":"132","author":"Song","year":"2018","journal-title":"Int. J. Therm. Sci."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Song, K.W., Shi, W.N., Wu, X., and Wang, L.B. (2020). Characteristics of flow symmetry and heat transfer of winglet pair in common flow down configuration. Symmetry, 12.","DOI":"10.3390\/sym12020209"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"114343","DOI":"10.1016\/j.applthermaleng.2019.114343","article-title":"Thermo-hydraulic performance optimization of wavy fin heat exchanger by combining delta winglet vortex generators","volume":"163","author":"Luo","year":"2019","journal-title":"Appl. Therm. Eng."}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/12\/2\/247\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T08:55:06Z","timestamp":1760172906000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/12\/2\/247"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,5]]},"references-count":30,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2020,2]]}},"alternative-id":["sym12020247"],"URL":"https:\/\/doi.org\/10.3390\/sym12020247","relation":{},"ISSN":["2073-8994"],"issn-type":[{"type":"electronic","value":"2073-8994"}],"subject":[],"published":{"date-parts":[[2020,2,5]]}}}