张美娟,魏衍举,张启霞,陈晟闽
ZHANG Meijuan,WEI Yanju,ZHANG Qixia,CHEN Shengmin

• 1:无锡职业技术学院汽车与交通学院
• 2:江苏大学汽车与交通工程学院
• 3:西安交通大学能源与动力工程学院

摘要(Abstract)：

燃用甲醇可使柴油机实现高效清洁燃烧，燃料的蒸发特性对燃料的混合、着火、燃烧过程影响显著。甲醇十六烷值较低，着火困难，添加正庚烷可提高甲醇燃料的十六烷值。搭建了液滴蒸发试验装置，采用单液滴挂滴测量方法，使用高速摄像机拍摄液滴蒸发图像，基于图像处理技术研究了正庚烷-甲醇液滴的蒸发过程。分析不同正庚烷掺混体积比(0、5%、10%、15%)和环境温度(100～500℃)对液滴蒸发特性的影响。结果表明，正庚烷-甲醇燃料液滴的蒸发特性遵循D~2定律，即液滴直径D与液滴初始直径D_0比值的平方(D/D_0)~2与蒸发时间呈线性关系。液滴相对面积随时间变化近似为一条斜率为负的直线。掺混体积比一定时，液滴蒸发速率随温度增加而增加。当温度从100℃增至500℃后，正庚烷掺混体积比0、5%、10%和15%的液滴单位面积蒸发速率分别增加了543%、639%、896%、556%。温度一定时，不同正庚烷添加剂掺混体积比的甲醇液滴蒸发的变化趋势基本相同。与纯甲醇相比，除200、300℃外，掺混体积比5%的正庚烷使液滴蒸发时间延长。100℃时，随正庚烷掺混体积比增加，液滴蒸发时间缩短；200℃时，随正庚烷掺混体积比增加，液滴蒸发时间延长；其余试验温度下，随正庚烷掺混体积比增加，液滴蒸发时间先延长后缩短。其中，在200、300、400、500℃,正庚烷掺混体积比从5%增至15%后，液滴蒸发时间分别延长了53.9%、17.1%、47.5%、53.1%。
Methanol fueling can make diesel engine achieve efficient and clean combustion. The evaporative properties of the fuel have a significant effect on the mixing, ignition and combustion process. Methanol has a low cetane number, which makes ignition difficult. The cetane number of methanol fuel can be increased by the addition of n-heptane. the droplet evaporation process of n-heptane methanol droplet was studied based on image processing technology by using the single droplet hanging measurement method and high-speed camera to capture the droplet evaporation image. The effects of different n-heptane blending volume ratios(0, 5%, 10%, 15%) and ambient temperatures(100-500 ℃) on the evaporation characteristics of droplets were analyzed. The results show that the evaporation characteristics of n-heptane-methanol droplet followed the D~2 law, which means that the square of the ratio of the droplet diameter D to the initial droplet diameter D_0((D/D_0)~2) is linearly related to the evaporation time. The trend of the relative area of the droplets with time is approximated as a straight line with a negative slope. The evaporation rate of droplets increases with the increase of temperature when the mixing ratio is fixed. The evaporation rates per unit area of droplets is increased by 543%, 639%, 896%, and 556% for 0, 5%, 10%, and 15% n-heptane blending ratios, respectively, when the temperature is increased from 100 ℃ to 500 ℃. The evaporation trends of methanol droplets with different n-heptane additive blending ratios are basically the same when the temperature is certain. Compared with pure methanol, 5% volume ratio of n-heptane prolongs the evaporation time of droplets except at 200 and 300 ℃. At 100 ℃, the droplet evaporation time is shortened with the increase of n-heptane blending ratio, while prolonged at 200 ℃. At the rest of the test temperatures, the droplet evaporation time is prolonged and then decreased with the increase of n-heptane blending ratio. At 200, 300, 400 and 500 ℃, the droplet evaporation time is prolonged by 53.9%, 17.1%, 47.5% and 53.1% when the n-heptane blending volume ratio increases from 5% to 15%, respectively.

关键词(KeyWords)： 柴油机;清洁燃料;甲醇;正庚烷;液滴;蒸发特性
diesel engine;clean fuels;methanol;n-heptane;droplet;evaporation characteristics

Abstract:

Keywords:

基金项目(Foundation): 国家自然科学基金资助项目(52176128,91741110,51776089);; 陕西省重点研发计划资助项目(No.2019ZDLGY15-10);; 江苏省高等职业院校专业带头人高端研修资助项目(2019GRFX111);; 江苏省高校自然科学研究面上资助项目(17KJD470004);; 江苏高校“青蓝工程”资助项目

作者(Author): 张美娟,魏衍举,张启霞,陈晟闽
ZHANG Meijuan,WEI Yanju,ZHANG Qixia,CHEN Shengmin

DOI: 10.13226/j.issn.1006-6772.21082001

参考文献(References)：

• [1] 崔普选.煤制甲醇技术发展评述[J].现代化工，2020,40(5):4-9.CUI Puxuan.Review on development of coal-to-methanol technologies[J].Modern Chemical Industry,2020,40(5):4-9.
• [2] 危红媛，姚春德，潘望，等.预喷油量对DMCC发动机燃烧和排放的影响[J].内燃机学报，2018,36(5):401-407.WEI Hongyuan,YAO Chunde,PAN Wang,et al.Effect of pilot injection quantity on combustion and emission characteristics of DMCC engine[J].Transactions of CSICE,2018,36(5):401-407.
• [3] 王辉，辛强之，姚安仁，等.船用柴油机应用柴油/甲醇二元燃料的性能特性研究[J].柴油机，2019,41(1):1-6,35.WANG Hui,XIN Qiangzhi,YAO Anren,et al .Performance study about marine engines with diesel-methanol dual fuel[J].Diesel Engine,2019,41(1):1-6,35.
• [4] 魏远文，黄海波，田维，等.甲醇用作柴油替代燃料的研究进展[J].农机化研究，2007(5):202-204,209.WEI Yuanwen,HUANG Haibo,TIAN Wei,et al.The study progress of methanol used as alternative diesel fuel[J].Journal of Agricultural Mechanization Research,2007(5):202-204,209.
• [5] 马力，仇性启，郑志伟，等.高温气流中液滴蒸发影响因素的数值研究[J].石油化工，2013,42(8):58-62.MA Li,CHOU Xingqi,ZHENG Zhiwei,et al.Numerical research on influencing factors of droplet evaporation in high temperature airflow[J].Petrochemical Technology,2013,42(8):58-62.
• [6] 段小龙，仇性启，李大树，等.高温气流中双液滴蒸发过程实验研究[J].工业加热，2014,43(1):1-4.DUAN Xiaolong,CHOU Xingqi,LI Dashu,et al.Experimental study on double-droplets evaporation in high temperature gas flow[J].Industrial Heating,2014,43(1):1-4.
• [7] 费舒波，齐运亮，李雁飞，等.高温高压下机油液滴蒸发特性的数值模拟[J].内燃机学报，2019,37(2):114-121.FEI Shubo,QI Yunliang,LI Yanfei,et al.Simulation for oil droplet evaporation under high-temperature and high-pressure conditions[J].Transactions of CSICE,2019,37(2):114-121.
• [8] 赵宇炜，杨龙滨，葛坤，等.不同来流温度下单液滴燃烧的数值模拟[J].燃烧科学与技术，2014,20(1):78-83.ZHAO Yuwei,YANG Longbin,GE Kun,et al.Numerical simulation of impacts of gas flow temperature on combustion characteristics of single droplet[J].Journal of Combustion Science and Technology,2014,20(1):78-83.
• [9] FITRIANA L ,NUGROHO R A A ,SAPUTRO H ,et al.The basic investigation of evaporation rate and burning temperature of various type of liquid fuels droplet[J].Materials Science and Engineering,2018,3434(3):1-4.
• [10] FENG M,WANG N,LI J,et al.Study on unsteady evaporation of n-heptane droplet in a heated tube[J].International Journal of Heat and Mass Transfer,2018,122(7):539-556.
• [11] BAEK S W,KIM H,CHANG D.A single n-heptane droplet behavior in rapid compression machine[J].International Journal of Heat & Mass Transfer,2014,69(2):247-255.
• [12] BANERJEE R.Numerical investigation of evaporation of a single ethanol/iso-octane droplet[J].Fuel,2013,107(9):724-739.
• [13] 李云风，王磊，王志成.采用幅度相移键控调制的分层空间调制算法[J].西安交通大学学报，2018,52(8):117-123.LI Yunfeng,WANG Lei,WANG Zhicheng.A Layered spatial modulation algorithm based on amplitude/phase-shift keying[J].Journal of Xi′an Jiaotong University,2018,52(8):117-123.
• [14] 梅莲，王忠，刘帅，等.煤液化柴油掺混甲醇柴油机试验研究[J].煤炭转化，2018,41(5):38-44,51.MEI Lian,WANG Zhong,LIU Shuai,et al.Study on engine fueled with mixture of coal liquefied diesel and methanol[J].Coal Conversion,2018,41(5):38-44,51.
• [15] 李瑞娜.甲醇/生物柴油混合燃料雾化及着火过程的研究[D].苏州：江苏大学，2016.
• [16] ZHU J L,LI R N,WANG Z,et al .Experimental research on the disruptive evaporation and the motion characteristics of secondary droplets for emulsified biodiesel with a suspended droplet configuration[J].ACS Omega,2021,6:17848-17860.
• [17] WANG J,WANG X,CHEN H,et al.Experimental study on puffing and evaporation characteristics of jatropha straight vegetable oil (SVO) droplets [J].International Journal of Heat and Mass Transfer,2018,119:392-399.
• [18] MEI D Q,SUN C,LI L C,et al.Evaporation characteristics of fuel sessile droplets with nanoparticles[J].Energy Sources Part A Recovery Utilization & Environmental Effects,2018,41(6):677-688.
• [19] GAN Y,QIAO L.Evaporation characteristics of fuel droplets with the addition of nanoparticles undernatural and forced convections[J].International Journal of Heat and Mass Transfer,2011,54:4913-4922.
• [20] 李健.平面被动式微混合器内混合特性研究及其在纳米颗粒制备中的应用[D].北京：北京工业大学，2013.