Thermal Performance Analysis of a Cross-Flow Automotive Radiator under Variable Air and Coolant Flow

Thermal Performance Analysis of a Cross-Flow Automotive Radiator under Variable Air and Coolant Flow | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Thermal Performance Analysis of a Cross-Flow Automotive Radiator under Variable Air and Coolant Flow Sanjay Mitkar This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7946285/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 14 You are reading this latest preprint version Abstract The study examines the thermal performance of a cross-flow automotive radiator typically used in internal combustion engine vehicles, where 8–30 kW of heat must be dissipated under varying operating conditions. Radiator cooling efficiency primarily depends on air velocity (1–6 m/s) and coolant flow rate (0.05–0.3 kg/s), with air-side management exerting the strongest influence. Experimental analysis showed a maximum coolant-side heat transfer rate of 26.25 kW, with Reynolds numbers between 16,650- 2,800 yielding a convective coefficient of 22.49 kW/m²K. On the air side, Reynolds numbers of 217–1,520 correspond to a heat transfer coefficient of 168 W/m²K and a peak heat flow of 23.8 kW. The overall heat transfer coefficient reached 167 W/m²K. Coolant temperatures decreased significantly along the radiator core, with low flow rates achieving large temperature drops (90°C to ~ 64.3°C), while higher flow rates enhanced total heat removal through increased turbulence. Variable air velocity from 1 m/s to 5 m/s markedly improved convective heat transfer, confirming the dominance of air-side effects. System-level analysis highlights that, since pump flow depends on engine speed, variable-speed fan control provides the primary means of adjusting heat rejection in real time, improving thermal efficiency and reducing energy consumption in modern automotive cooling systems. Physical sciences/Energy science and technology Physical sciences/Engineering Physical sciences/Physics Radiator cross flow heat exchanger convective heat transfer coolant Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 29 Dec, 2025 Reviews received at journal 30 Nov, 2025 Reviews received at journal 25 Nov, 2025 Reviews received at journal 24 Nov, 2025 Reviews received at journal 19 Nov, 2025 Reviewers agreed at journal 18 Nov, 2025 Reviewers agreed at journal 16 Nov, 2025 Reviewers agreed at journal 14 Nov, 2025 Reviewers agreed at journal 14 Nov, 2025 Reviewers invited by journal 14 Nov, 2025 Editor assigned by journal 14 Nov, 2025 Editor invited by journal 12 Nov, 2025 Submission checks completed at journal 05 Nov, 2025 First submitted to journal 05 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Flow\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Radiator, cross flow heat exchanger, convective heat transfer, coolant","lastPublishedDoi":"10.21203/rs.3.rs-7946285/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7946285/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe study examines the thermal performance of a cross-flow automotive radiator typically used in internal combustion engine vehicles, where 8\u0026ndash;30 kW of heat must be dissipated under varying operating conditions. Radiator cooling efficiency primarily depends on air velocity (1\u0026ndash;6 m/s) and coolant flow rate (0.05\u0026ndash;0.3 kg/s), with air-side management exerting the strongest influence. Experimental analysis showed a maximum coolant-side heat transfer rate of 26.25 kW, with Reynolds numbers between 16,650- 2,800 yielding a convective coefficient of 22.49 kW/m\u0026sup2;K. On the air side, Reynolds numbers of 217\u0026ndash;1,520 correspond to a heat transfer coefficient of 168 W/m\u0026sup2;K and a peak heat flow of 23.8 kW. The overall heat transfer coefficient reached 167 W/m\u0026sup2;K. Coolant temperatures decreased significantly along the radiator core, with low flow rates achieving large temperature drops (90\u0026deg;C to ~\u0026thinsp;64.3\u0026deg;C), while higher flow rates enhanced total heat removal through increased turbulence. Variable air velocity from 1 m/s to 5 m/s markedly improved convective heat transfer, confirming the dominance of air-side effects. System-level analysis highlights that, since pump flow depends on engine speed, variable-speed fan control provides the primary means of adjusting heat rejection in real time, improving thermal efficiency and reducing energy consumption in modern automotive cooling systems.\u003c/p\u003e","manuscriptTitle":"Thermal Performance Analysis of a Cross-Flow Automotive Radiator under Variable Air and Coolant Flow","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-25 19:37:10","doi":"10.21203/rs.3.rs-7946285/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-29T14:59:42+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-01T02:03:10+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-25T05:20:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-24T14:30:04+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-19T12:54:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"105797166528899173572405411030263754240","date":"2025-11-19T01:31:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"41727306173966529271748765742482472570","date":"2025-11-16T10:43:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"244721974475402135428481707892170288480","date":"2025-11-14T14:56:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"138383118222936089486155480353826282208","date":"2025-11-14T10:53:03+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-14T10:40:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-14T10:37:52+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-12T14:38:27+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-05T07:07:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-11-05T07:04:13+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a7ce20f3-1bb1-4207-bbcf-b1bdbb3815d1","owner":[],"postedDate":"November 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[{"id":58605244,"name":"Physical sciences/Energy science and technology"},{"id":58605245,"name":"Physical sciences/Engineering"},{"id":58605246,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2025-12-29T15:08:34+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-25 19:37:10","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7946285","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7946285","identity":"rs-7946285","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}