| 喷油压力及背压对丁醇柴油喷雾影响的模拟及验证 |
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| 引用本文： | 吴健,花阳,王站成,徐斌,朱莉莉.喷油压力及背压对丁醇柴油喷雾影响的模拟及验证[J].农业工程学报,2014,30(21):47-54. |
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| 作者姓名： | 吴健 花阳 王站成 徐斌 朱莉莉 |
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| 作者单位： | 河南科技大学车辆与交通工程学院,洛阳,471003 |
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| 基金项目： | 车用生物燃料技术国家重点实验室开放课题（2013019） |
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| 摘 要： | 为深入了解丁醇柴油的喷雾特性,该文根据喷雾可视化试验结果,利用AVL Fire软件建立了耦合喷嘴内流动的丁醇柴油喷雾模型,并依据试验结果证明了模型的准确性。通过该模型研究了喷油压力、背压和掺混比对丁醇柴油喷雾的影响,计算了各种因素对混合燃料的油束发展、喷雾贯穿距、索特平均直径(sauter mean diameter,SMD)、速度场和浓度场的影响。结果表明:随喷油压力和背压的变化,正丁醇体积分数为25%的丁醇柴油混合燃料(记为N25)的油束形态基本不变;随喷油压力的升高,N25的贯穿距增加,SMD减小,油束和环境的卷吸增强,油束中心速度和轴线附近浓度均增加;随背压的升高,N25贯穿距减小,SMD在喷雾初期稍降,喷雾中后期基本不变,油束中心的速度降低,浓度增加;随正丁醇掺混比的增加,贯穿距和SMD均逐渐降低;随环境温度的升高,贯穿距增加,SMD在温度由293.15 K升高后明显降低,而后随温度升高变化不大。该文的研究分析了多种因素对丁醇柴油喷雾的影响,为其作为替代燃料的应用提供了理论支持。
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| 关 键 词： | 燃料 喷雾 模型 正丁醇 柴油 喷油压力 环境背压 数值模拟 |
| 收稿时间： | 9/4/2014 12:00:00 AM |
| 修稿时间： | 2014/10/22 0:00:00 |
Simulation and verification on spray influence of butanol/diesel blends effected by injection pressure and backpressure |
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| Wu Jian,Hua Yang,Wang Zhancheng,Xu Bin and Zhu Lili.Simulation and verification on spray influence of butanol/diesel blends effected by injection pressure and backpressure[J].Transactions of the Chinese Society of Agricultural Engineering,2014,30(21):47-54. |
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| Authors: | Wu Jian Hua Yang Wang Zhancheng Xu Bin and Zhu Lili |
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| Institution: | Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China;Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China;Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China;Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China;Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China |
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| Abstract: | Abstract: Butanol is known as a typical second generation biofuel, and it has many advantages as an alternative fuel for engine. At present, the main studies about butanol concentrate on the combustion and emission characteristics. But the research on the spray characteristics is less. The spray atomization of fuel is a key factor that influences the combustion and emission characteristics of diesel engine. So it is important to research the spray characteristics of butanol and diesel blended fuel in depth. First conduct the spray visualization experiment on the spray test bench of high pressure common rail. Then according to the test results, this paper established nozzle flow model and spray model with the aid of AVL Fire software respectively. The nozzle flow and spray are regarded as an unified whole to research the spray characteristics of butanol and diesel fuel mix, and the calculation result of nozzle multiphase flow is used as the initial and boundary conditions for the spray simulation. Then the accuracy of the model is verified by the contrast of spray penetration and spray image. The influence of injection pressure, environment pressure and blending ratio on spray characteristic of n-butanol/diesel blends was studied by the model. And calculate the influence of various factors on the spray form development, spray penetration, SMD, velocity field and concentration field of blended fuel. In this paper, Nn indicates n-butanol and diesel blended fuel with the volume fraction of n-butanol is n. The results show that with the change of injection pressure and environment pressure, the spray form of blended fuel N25 remain unchanged basically. And the differences of spray form mainly displays in the spray penetration and spray cone angle. With the increase of injection pressure, the spray penetration of N25 increases gradually, and sauter mean diameter (SMD) decreases gradually. Then select two points in the velocity field. By comparing the speed of the two points, it can be seen that the speeds of the two points all increase with the increase of injection pressure. This can indicate that the air entrainment enhances with the raise of injection pressure. And the spray center speed and concentration near the axis all increase, with the increase of injection pressure. According to the results of the research on back pressure, with the increase of environment back pressure, the initial velocity of droplet decreases and resistance increases, so the spray penetration of N25 reduces. And SMD is basically unchanged in middle and later of the spray. Because initial velocity of droplet is reduced, which is not beneficial for the droplet broken. Meanwhile with the increase of backpressure, environment density increase, the interaction of environment and fuel enhance, which make the droplet broken quickly. The spray center speed reduces, concentration near the axis increases. According to the results of the research on blending ratio, with the increase of n-butanol blending ratio, the viscosity and surface tension all decrease, then the droplets is easily broken, which leads to the spray penetration and SMD all reduce, and the atomization becomes better. With the increase of environment temperature, the spray penetration of N25 reduces, and SMD significantly decreases after temperature increased by 293.15 K. And then there is a little change with the temperature increasing. In this paper, the spray model is much closer to the actual situation because of coupling the flow inside the nozzle. This paper researches and analyzes the influence of various factors on spray macroscopic and microscopic characteristics of butanol and diesel blended fuel. So this paper could provide a theoretical support for the application of butanol as an alternative fuel for engine. |
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| Keywords: | fuels spraying models n-butanol diesel injection pressure environment pressure numerical simulation |
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