[Objective] The primary aim of this research is to address the critical issue of potential fires arising from fuel spillage on hot surfaces. This work is vital owing to the inherent risks associated with such scenarios, particularly in industrial environments where accidental contact between flammable liquids and hot surfaces can lead to disastrous outcomes. A comprehensive understanding of the evaporation patterns and heat transfer mechanisms of fuel droplets on heated surfaces is imperative for mitigating these fire hazards. [Methods] By undertaking this investigation, the goal is to provide valuable insights that can inform safety protocols, design considerations, and risk assessment strategies in various industries dealing with flammable substances. Glass heating substrates serve as the foundation for the investigations, allowing us to simulate real-world scenarios in which fuel droplets come into contact with hot surfaces. To maximize the infrared transmittance of the glass, we increase the transmittance film on the quartz glass to 93%-96%. This study encompasses a range of representative fuels, including acetic acid, ethanol, acetone, ethyl acetate, n-heptane, and cyclohexane, to ensure a comprehensive understanding of the diverse fuel properties. In experimental analysis, we employ state-of-the-art infrared imaging technology in conjunction with a robust volume estimation method. This combination of tools enables us to precisely observe and measure the evaporation behavior of the selected fuel droplets. [Results] This study had yielded innovative and noteworthy results that significantly contributed to the current body of knowledge in this field. Unique thermal patterns on the surfaces of different fuel droplets were observed, providing a detailed understanding of the evaporation process. Hydrothermal waves (HTWs) and Bénard-Marangoni (B-M) cells were identified on acetic acid and ethanol droplets, representing a novel finding with implications for the broader understanding of thermal dynamics on liquid surfaces. A particular highlight was the identification of a previously unreported double-vortex thermal pattern on the surface of cyclohexane droplets. This discovery added a layer of complexity to the existing literature, highlighting the complexity and diversity of thermal behaviors in the context of fuel evaporation on heated surfaces. It founded that the contact angle exhibited minimal variation, generally staying within a range of 10 degrees for all six fuels. Consequently, when evaluating the droplet volume using the volume estimation method, it became clear that the liquid was not significantly influenced by changes in the contact angle, and such variations didn't affect the primary results. [Conclusions] In conclusion, this research illuminates the intricate interplay between fuel droplets and hot surfaces, providing crucial insights for fire prevention strategies and safety measures. The observed thermal patterns, including the novel double-vortex pattern, provide a deeper understanding of the underlying mechanisms governing fuel evaporation. This knowledge is instrumental in refining safety protocols, designing effective preventive measures, and informing future research in the broader field of fire safety and risk management. The findings of this investigation underscore the need to consider specific fuel properties and surface characteristics when developing targeted safety strategies for industries dealing with flammable substances. In the future, the goal is to integrate these insights into practical applications, potentially enhancing the safety and resilience of industrial processes involving flammable liquids.
[1] LI Y L, LI S X. Evaporation and ignition of the leaked fuel by a hot plate[J]. Process in Safety Science and Technology Part B, 2002, 3:1311-1316.
[2] AL QUBEISSI M, SAZHIN S S, ELWARDANY A E. Modelling of blended diesel and biodiesel fuel droplet heating and evaporation[J]. Fuel, 2017, 187:349-355.
[3] PINHEIRO A P, VEDOVOTO J M, DA SILVEIRA NETO A, et al. Ethanol droplet evaporation:Effects of ambient temperature, pressure and fuel vapor concentration[J]. International Journal of Heat and Mass Transfer, 2019, 143:118472.
[4] WANG Z W, YUAN B, HUANG Y H, et al. Progress in experimental investigations on evaporation characteristics of a fuel droplet[J]. Fuel Processing Technology, 2022, 231:107243.
[5] ZHANG Y, HUANG R H, HUANG Y H, et al. Effect of ambient temperature on the puffing characteristics of single butanol-hexadecane droplet[J]. Energy, 2018, 145:430-441.
[6] GROSSHANS H, GRIESING M, MÖNCKEDIECK M, et al. Numerical and experimental study of the drying of Bi-component droplets under various drying conditions[J]. International Journal of Heat and Mass Transfer, 2016, 96:97-109.
[7] BHATTACHARYA P, SAMANTA A N, CHAKRABORTY S. Spray evaporative cooling to achieve ultra fast cooling in runout table[J]. International Journal of Thermal Sciences, 2009, 48(9):1741-1747.
[8] KIM J. Spray cooling heat transfer:The state of the art[J]. International Journal of Heat and Fluid Flow, 2007, 28(4):753-767.
[9] DEEGAN R D, BAKAJIN O, DUPONT T, et al. Capillary flow as the cause of ring stains from dried liquid drops[J]. Nature, 1997, 389(6653):827-829.
[10] GARNIER N, CHIFFAUDEL A, DAVIAUD F. Hydrothermal waves in a disk of fluid[M]//MUTABAZI I, WESFREID J E, GUYON E. Dynamics of spatio-temporal cellular structures:Henri Bénard centenary review. New York:Springer, 2006:147-161.
[11] LI Y R, ZHANG L, ZHANG L, et al. Experimental study on prandtl number dependence of thermocapillary-buoyancy convection in czochralski configuration with different depths[J]. International Journal of Thermal Sciences, 2018, 130:168-182.
[12] BÉNARD H. Les tourbillons cellulaires dans une nappe liquide-Méthodes optiques d'observation et d'enregistrement[J]. Journal de Physique Théorique et Appliquée, 1901, 10(1):254-266.
[13] SEFIANE K, MOFFAT J R, MATAR O K, et al. Self-excited hydrothermal waves in evaporating sessile drops[J]. Applied Physics Letters, 2008, 93(7):074103.
[14] GLEASON K, VOOTA H, PUTNAM S A. Steady-state droplet evaporation:Contact angle influence on the evaporation efficiency[J]. International Journal of Heat and Mass Transfer, 2016, 101:418-426.
[15] ZHANG N L, CHAO D F. Flow visualization in evaporating liquid drops and measurement of dynamic contact angles and spreading rate[J/OL]. Journal of Flow Visualization and Image Processing.(2008-02-04)[2023-10-08]. DOI:10.1615/JFlowVisImageProc.v8.i2-3.170.
[16] ZHANG N L, CHAO D F. A new laser shadowgraphy method for measurements of dynamic contact angle and simultaneous flow visualization in a sessile drop[J]. Optics&Laser Technology, 2002, 34(3):243-248.
[17] SEFIANE K, FUKATANI Y, TAKATA Y, et al. Thermal patterns and hydrothermal waves (HTWs) in volatile drops[J]. Langmuir, 2013, 29(31):9750-9760.
[18] BRUTIN D, SOBAC B, RIGOLLET F, et al. Infrared visualization of thermal motion inside a sessile drop deposited onto a heated surface[J]. Experimental Thermal and Fluid Science, 2011, 35(3):521-530.
[19] GHASEMI H, WARD C A. Energy transport by thermocapillary convection during sessile-water-droplet evaporation[J]. Physical Review Letters, 2010, 105(13):136102.
[20] HU H, LARSON R G. Analysis of the effects of marangoni stresses on the microflow in an evaporating sessile droplet[J]. Langmuir, 2005, 21(9):3972-3980.
[21] ZHANG K, MA L R, XU X F. Temperature distribution along the surface of evaporating droplets[J]. Physical Review E, 2014, 89(3):032404.
[22] YANG K, HONG F J, CHENG P. A fully coupled numerical simulation of sessile droplet evaporation using arbitrary lagrangian-eulerian formulation[J]. International Journal of Heat and Mass Transfer, 2014, 70:409-420.
[23] CHEN Y H, HONG F J, CHENG P. Transient flow patterns in an evaporating sessile drop:A numerical study on the effect of volatility and contact angle[J]. International Communications in Heat and Mass Transfer, 2020, 112:104493.
[24] 唐甜,石万元.固定接触角蒸发液滴内Marangoni对流数值模拟[J].工程热物理学报, 2017, 38(4):792-799.TANG T, SHI W Y. Marangoni convection in evaporating sessile droplet with constant angle by numerical simulation[J]. Journal of Engineering Thermophysics, 2017, 38(4):792-799.(in Chinese)
[25] LU G, DUAN Y Y, WANG X D, et al. Internal flow in evaporating droplet on heated solid surface[J]. International Journal of Heat and Mass Transfer, 2011, 54(19-20):4437-4447.
[26] WANG T S, SHI W Y. Influence of substrate temperature on Marangoni convection instabilities in a sessile droplet evaporating at constant contact line mode[J]. International Journal of Heat and Mass Transfer, 2019, 131:1270-1278.
[27] WANG T S, SHI W Y. Transition of Marangoni convection instability patterns during evaporation of sessile droplet at constant contact line mode[J]. International Journal of Heat and Mass Transfer, 2020, 148:119138.
[28] 李晶.座滴图像求解界面张力计算方法的研究[J].中南矿冶学院学报, 1989, 20(5):562-567.LI J. A study of computation method and program for calculating interfacial tension by curve fitting to the picture of sessile drop[J]. Journal of Central South Institute of Mining and Metallurgy, 1989, 20(5):562-567.(in Chinese)
[29] HUBER M L. NIST thermophysical properties of hydrocarbon mixtures database (SUPERTRAPP), version 3.2[M]. Gaithersburg:National Institute of Standards and Technology Standard Reference Database, 2007.
[30] MOFFAT R J. Describing the uncertainties in experimental results[J]. Experimental Thermal and Fluid Science, 1988, 1(1):3-17.
[31] SMITH M K, DAVIS S H. Instabilities of dynamic thermocapillary liquid layers. Part 1. Convective instabilities[J]. Journal of Fluid Mechanics, 1983, 132:119-144.
[32] TRUSKETT V N, STEBE K J. Influence of surfactants on an evaporating drop:Fluorescence images and particle deposition patterns[J]. Langmuir, 2003, 19(20):8271-8279.
[33] 叶爽,李友荣,吴春梅,等.加热基底上附壁液滴蒸发动力学实验研究[J].工程热物理学报, 2021, 42(10):2625-2632. YE S, LI Y R, WU C M, et al. Experimental study on evaporation dynamic of sessile droplet on heated substrate[J]. Journal of Engineering Thermophysics, 2021, 42(10):2625-2632.(in Chinese)
[34] YE S, ZHANG L, WU C M, et al. Experimental investigation of evaporation dynamic of sessile droplets in pure vapor environment with low pressures[J]. International Journal of Thermal Sciences, 2020, 149:106213.
[35] GIRARD F, ANTONI M, FAURE S, et al. Evaporation and marangoni driven convection in small heated water droplets[J]. Langmuir, 2006, 22(26):11085-11091.
[36] SOBAC B, BRUTIN D. Thermocapillary instabilities in an evaporating drop deposited onto a heated substrate[J]. Physics of Fluids, 2012, 24(3):032103.
[37] JOSYULA T, WANG Z Y, ASKOUNIS A, et al. Evaporation kinetics of pure water drops:Thermal patterns, marangoni flow, and interfacial temperature difference[J]. Physical Review E, 2018, 98(5):052804.
[38] CHEN P, HARMAND S, OUENZERFI S, et al. Marangoni flow induced evaporation enhancement on binary sessile drops[J]. The Journal of Physical Chemistry B, 2017, 121(23):5824-5834.
[39] KITA Y, ASKOUNIS A, KOHNO M, et al. Induction of marangoni convection in pure water drops[J]. Applied Physics Letters, 2016, 109(17):171602.
[40] GATAPOVA E Y, SEMENOV A A, ZAITSEV D V, et al. Evaporation of a sessile water drop on a heated surface with controlled wettability[J]. Colloids and Surfaces A:Physicochemical and Engineering Aspects, 2014, 441:776-785.
[41] SOBAC B, BRUTIN D. Thermal effects of the substrate on water droplet evaporation[J]. Physical Review E, 2012, 86(2):021602.
