Design and CFD-Based Optimization of Multi-Slit Pintle Injector for High Pressure LOx-Methane Rocket Engine

Design and CFD-Based Optimization of Multi-Slit Pintle Injector for High Pressure LOx-Methane Rocket Engine | 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 Research Article Design and CFD-Based Optimization of Multi-Slit Pintle Injector for High Pressure LOx-Methane Rocket Engine Dhakhshit CVS, Abhishek Sharma, MathanKumar S, Biju T Kuzhiveli This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9080973/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Increase in demand for sustainable technologies has accelerated the use of environmentally friendly propellants in rocket propulsion. Liquid oxygen (LOx) and methane (CH₄) have gained attention as a green alternative to hypergolic propellants due to their high performance, non-toxic nature, and in-situ resource utilization potential. Injector plays a key role in governing mixing, combustion efficiency, and stability. Throttling capability is essential for reusable launch vehicles and planetary landers, where precise thrust control is required. Pintle injectors address these needs by offering smooth throttling, reduced combustion instabilities, and reliable operation. This study presents design and analysis of an oxidizer centred pintle injector for a high-pressure LOx-methane engine, with the objective of optimizing the pintle design through CFD simulations. An analytical procedure to design multi-slit pintle injector is presented and combustion modelling at supercritical conditions is carried out to study the influence of key geometric parameters. Flamelet Generated Manifold (FGM) combustion model with the Soave Redlich Kwong (SRK) real fluid EoS is used in a RANS framework. Results show that injector geometry strongly influences mixing behaviour. Variations in annular gap and skip ratio have no substantial impact on mixing performance, whereas pintle geometric parameters play a dominant role in mixing. Decrease in the number of slits leads to improved mixing efficiency. Further, the single row slit configuration enhances mixing even at higher slit numbers as the interaction area between the LOx and methane significantly increases. This work offers systematic insight into pintle injector design optimization for LOx-methane propulsion systems and supports the development of efficient and sustainable rocket engines. LOx-methane Pintle Injector Supercritical Combustion FGM Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 28 Apr, 2026 Reviews received at journal 05 Apr, 2026 Reviews received at journal 28 Mar, 2026 Reviewers agreed at journal 28 Mar, 2026 Reviewers agreed at journal 25 Mar, 2026 Reviewers agreed at journal 24 Mar, 2026 Reviewers invited by journal 23 Mar, 2026 Editor assigned by journal 23 Mar, 2026 Submission checks completed at journal 20 Mar, 2026 First submitted to journal 10 Mar, 2026 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. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9080973","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":611165488,"identity":"1c2e2c82-df30-44d9-9413-cbfe92a560c1","order_by":0,"name":"Dhakhshit CVS","email":"","orcid":"","institution":"National Institute of Technology Calicut","correspondingAuthor":false,"prefix":"","firstName":"Dhakhshit","middleName":"","lastName":"CVS","suffix":""},{"id":611165489,"identity":"e0bd21b0-d4ca-4634-b2a9-30184ff39923","order_by":1,"name":"Abhishek Sharma","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYFACxgYgcQDMegAkePhI0cJsANLCRqRVYC1sEmCSkFr+GcnNHxj+3JE3n3b4WeXXHDsZNgbmh49u4NEicSOxTYKx7ZnhnNtpZrdltyUDHcZmbJyDz5ozB9uA3jnMOEM6wey25DZmoBYeNml8WuTPHAQ57LD9DOn0b8WS2+oJazE43tggwcB2OHGGdI4Z48dthwlrMTze2CaR2HY4GailWJpx23EeNmYCfpE7zP74w4c/h22BDtv48ee2ant+9uaHj/F6HwQSoDQzD5gkpBwZMP4gRfUoGAWjYBSMGAAAuldIdyPWtrgAAAAASUVORK5CYII=","orcid":"","institution":"Indian Space Research Organisation","correspondingAuthor":true,"prefix":"","firstName":"Abhishek","middleName":"","lastName":"Sharma","suffix":""},{"id":611165490,"identity":"5943d9e6-324a-4bf1-b54a-75c99152c3b3","order_by":2,"name":"MathanKumar S","email":"","orcid":"","institution":"Indian Space Research Organisation","correspondingAuthor":false,"prefix":"","firstName":"MathanKumar","middleName":"","lastName":"S","suffix":""},{"id":611165492,"identity":"b125a605-117a-4bbf-8e9a-2df9a083e052","order_by":3,"name":"Biju T Kuzhiveli","email":"","orcid":"","institution":"National Institute of Technology Calicut","correspondingAuthor":false,"prefix":"","firstName":"Biju","middleName":"T","lastName":"Kuzhiveli","suffix":""}],"badges":[],"createdAt":"2026-03-10 08:09:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9080973/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9080973/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105401966,"identity":"6dd347ca-e91c-46ff-b30f-ab1a1d344809","added_by":"auto","created_at":"2026-03-25 15:29:44","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2110056,"visible":true,"origin":"","legend":"","description":"","filename":"PnESubmit.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9080973/v1_covered_046eb7da-7085-4af0-a0f0-60b4a322cfdc.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Design and CFD-Based Optimization of Multi-Slit Pintle Injector for High Pressure LOx-Methane Rocket Engine","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":"propulsion-and-energy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Propulsion and Energy](https://link.springer.com/journal/44270)","snPcode":"44270","submissionUrl":"https://submission.springernature.com/new-submission/44270/3","title":"Propulsion and Energy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"LOx-methane, Pintle Injector, Supercritical Combustion, FGM","lastPublishedDoi":"10.21203/rs.3.rs-9080973/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9080973/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIncrease in demand for sustainable technologies has accelerated the use of environmentally friendly propellants in rocket propulsion. 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