Eruptive burning of concave PMMA: Effect of curvature and width

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2025-10-07 DOI:10.1016/j.ijthermalsci.2025.110367

Rongwei Bu , Chuangang Fan , Zhenyu Gao , Zengguang Liang , Guanjie Rao , Wenlong Wang , Tong Xu

{"title":"Eruptive burning of concave PMMA: Effect of curvature and width","authors":"Rongwei Bu , Chuangang Fan , Zhenyu Gao , Zengguang Liang , Guanjie Rao , Wenlong Wang , Tong Xu","doi":"10.1016/j.ijthermalsci.2025.110367","DOIUrl":null,"url":null,"abstract":"<div><div>Polymethyl methacrylate (PMMA) is extensively utilized in the design of various architectural structures, including concave configurations. However, its inherent flammability poses a significant potential fire hazard. Investigation of upward flame spread over concave surfaces has been restricted to flame spread parameters, while the associated burning behaviors have not yet been addressed. In this study, 36 groups of fire experiments were performed on 3 mm thick PMMA with varying curvature (denoted by K, 0.52–2.00 m-1) and width (W, 2.5–15.0 cm). The results reveal that the mass loss rate undergoes an eruptive growth when K ≥ 1.41 m-1. By introducing a dimensionless parameter Γ, this burning behavior is quantitatively described using a piecewise power-law correlation between Γ and the Grashof number Grx. The critical occurrence of eruptive burning behavior is identified at Grx ≈ 3 × 107. For Grx < 3 × 107, flame convection mode in the pyrolysis zone is governed by natural convection, whereas forced convection becomes gradually dominant when Grx ≥ 3 × 107. Subsequently, based on this critical threshold, the flame spread model before the occurrence of eruptive phenomenon is developed. This model reflects a power-law relationship between flame spread rate and pyrolysis length, with an average power exponent of 1.24.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110367"},"PeriodicalIF":5.0000,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Thermal Sciences","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1290072925006908","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}

引用次数: 0

Abstract

Polymethyl methacrylate (PMMA) is extensively utilized in the design of various architectural structures, including concave configurations. However, its inherent flammability poses a significant potential fire hazard. Investigation of upward flame spread over concave surfaces has been restricted to flame spread parameters, while the associated burning behaviors have not yet been addressed. In this study, 36 groups of fire experiments were performed on 3 mm thick PMMA with varying curvature (denoted by K, 0.52–2.00 m^-1) and width (W, 2.5–15.0 cm). The results reveal that the mass loss rate undergoes an eruptive growth when K ≥ 1.41 m^-1. By introducing a dimensionless parameter Γ, this burning behavior is quantitatively described using a piecewise power-law correlation between Γ and the Grashof number Gr_x. The critical occurrence of eruptive burning behavior is identified at Gr_x ≈ 3 × 10⁷. For Gr_x < 3 × 10⁷, flame convection mode in the pyrolysis zone is governed by natural convection, whereas forced convection becomes gradually dominant when Gr_x ≥ 3 × 10⁷. Subsequently, based on this critical threshold, the flame spread model before the occurrence of eruptive phenomenon is developed. This model reflects a power-law relationship between flame spread rate and pyrolysis length, with an average power exponent of 1.24.

查看原文本刊更多论文

凹型PMMA的爆发燃烧：曲率和宽度的影响

聚甲基丙烯酸甲酯（PMMA）广泛应用于各种建筑结构的设计，包括凹形结构。然而，其固有的可燃性构成了重大的潜在火灾危险。火焰在凹表面上向上传播的研究仅限于火焰传播参数，而相关的燃烧行为尚未得到解决。本研究采用36组不同曲率（K, 0.52-2.00 m-1）和宽度（W, 2.5-15.0 cm）的3 mm厚PMMA进行了火灾实验。结果表明，当K≥1.41 m-1时，质量损失率呈爆发式增长。通过引入无量纲参数Γ，这种燃烧行为可以用Γ和Grashof数Grx之间的分段幂律相关性来定量描述。在Grx≈3 × 107处确定了喷发燃烧行为的临界发生点。对于Grx <； 3 × 107，热解区火焰对流模式以自然对流为主，而当Grx≥3 × 107时，强迫对流逐渐成为主导。在此基础上，建立了火山爆发前的火焰蔓延模型。该模型反映了火焰蔓延速率与热解长度之间的幂律关系，平均幂指数为1.24。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.