Implementation of isoconversional pyrolysis kinetics in a finite-element model of charring ablation

Implementation of isoconversional pyrolysis kinetics in a finite-element model of charring ablation | 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 Implementation of isoconversional pyrolysis kinetics in a finite-element model of charring ablation Kalid Kassa, Qasem Ahmed Drmosh, Sheriffdeen Anafi, Suhail Hyder Vattathurvalappil, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8928318/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Constant-parameter Arrhenius models for phenolic-impregnated carbon ablator (PICA) often match surface temperature, yet systematically overstate char recession. This study implements isoconversion kinetics extracted from multi-rate TGA via Flynn–Wall–Ozawa and embedded in UMATHT for PICA, with tabulated activation energy and pre-exponential factor {E(α), A(α)} advanced at integration points and coupled to conduction, pyrolysis-gas enthalpy, radiative and convective exchange with blowing, and mesh motion. Validation against oxy-acetylene tests shows two main improvements: surface-temperature plateaus remain within the measured 2250–2500 K band while avoiding the Arrhenius overshoot, and mid-range predictions fall by 60–120 K toward the data. Recession bias is reduced by ∼ 39%, from up to fourteen-fold overprediction to ∼ 0.7–3.5× the experimental mean (≈ 0.24 mm s−1). Joint interpretation of temperature history, recession-depth kinetics, and heating-rate fields shows a traveling subsurface maximum that weakens with time and reduces char consumption. Because a single convective coefficient cannot match both temperature and recession, boundary closure limits fidelity. Aeronautics and Astronautics Charring ablation Isoconversional kinetics Flynn–Wall–Ozawa (FWO) Multi-rate TGA Phenolic-impregnated carbon ablator Finite element analysis (FEA) Full Text Additional Declarations The authors declare no competing interests. Supplementary Files ABAQUSinputfileandsupportingthermochemicaldataforcharringablationmodelingwithCSVfiles.zip Cite Share Download PDF Status: Posted Version 1 posted 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-8928318","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":594614484,"identity":"af48d325-d360-4b0c-b8da-26264a686086","order_by":0,"name":"Kalid Kassa","email":"","orcid":"https://orcid.org/0009-0003-9901-1593","institution":"King Fahd University of Petroleum and Minerals","correspondingAuthor":false,"prefix":"","firstName":"Kalid","middleName":"","lastName":"Kassa","suffix":""},{"id":594614486,"identity":"de9237f0-eac0-46a7-9a0f-b6c74ab73379","order_by":1,"name":"Qasem Ahmed Drmosh","email":"","orcid":"","institution":"King Fahd University of Petroleum and Minerals","correspondingAuthor":false,"prefix":"","firstName":"Qasem","middleName":"Ahmed","lastName":"Drmosh","suffix":""},{"id":594614487,"identity":"99a398b4-3a7a-4fce-9db7-6a84722def6b","order_by":2,"name":"Sheriffdeen Anafi","email":"","orcid":"","institution":"King Fahd University of Petroleum and Minerals","correspondingAuthor":false,"prefix":"","firstName":"Sheriffdeen","middleName":"","lastName":"Anafi","suffix":""},{"id":594614488,"identity":"dfc5bc9e-e2c3-4857-a7b0-c9ffec830aa5","order_by":3,"name":"Suhail Hyder Vattathurvalappil","email":"","orcid":"","institution":"King Fahd University of Petroleum and Minerals","correspondingAuthor":false,"prefix":"","firstName":"Suhail","middleName":"Hyder","lastName":"Vattathurvalappil","suffix":""},{"id":594614485,"identity":"67d06af9-7721-4b58-a45f-a0671ec532f4","order_by":4,"name":"Abrar H. 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