AN EXPERIMENTAL STUDY ON EFFERVESCENT ATOMIZATION OF BIO-OIL FUELS
AN EXPERIMENTAL STUDY ON EFFERVESCENT ATOMIZATION OF BIO-OIL FUELS
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生物油燃料泡腾雾化的实验研究
DOI：
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发表时间：
2012
期刊：
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通讯作者：
R. Ravikrishna
中科院分区：
文献类型：
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作者：
Madan Mohan Avulapati;R. Ravikrishna
本文介绍了对麻风树和水黄皮属纯植物油喷雾剂的详细表征工作。这些生物燃料的喷雾特性进行了比较与柴油。研究了不同喷射压力和气液比下的宏观和微观喷雾特性。粒子/液滴成像分析（PDIA）技术沿着直接成像方法用于喷雾表征的目的。由于其较高的粘度，在给定的GLR下，与柴油以及柴油和纯植物油的共混物相比，纯植物油显示出较差的雾化。纯植物油喷雾表现出较低的喷雾锥角相比，柴油和混合物在较低的GLR。然而，在较高的GLR下，差异不显著。在出口孔下游100 mm处的液滴尺寸测量显示Sauter平均直径（SMD）直径随着GLR的增加而减小。对于混合物和纯植物油，观察到SMD的径向变化。纯油显示出更大的变化时，相比的共混物。喷雾不稳定性的特征在于基于图像到图像的平均液滴直径的变化和喷雾锥角的波动。结果表明，与柴油和混合物相比，纯植物油喷雾在较低的GLR下更不稳定。确定了一个临界GLR，在该临界GLR处喷雾变得稳定。喷雾操作的三个制度，即“稳定喷雾”，“脉动喷雾”和“喷雾和不间断的液体射流”被确定在这些纯植物油的注射压力GLR参数空间。出口孔内的两相流成像表明，对于纯植物油，在低GLR下的流动是高度瞬态的，并且观察到泡状、段塞状和环形两相流状态。然而，在较高的GLR喷雾是稳定的，只有环形流制度进行了观察。
This paper presents the work on detailed characterization of effervescent spray of Jatropha and Pongamia pure plant oils. The spray characteristics of these biofuels are compared with those of diesel. Both macroscopic and microscopic spray characteristics at different injection pressures and gas-to-liquid ratio (GLR) have been studied. The particle/droplet imaging analysis (PDIA) technique along with direct imaging methods are used for the purpose of spray characterization. Due to their higher viscosity, pure plant oils showed poor atomization compared to diesel and a blend of diesel and pure plant oil at a given GLR. Pure plant oil sprays showed a lower spray cone angle when compared to diesel and blends at lower GLRs. However, the difference is not significant at higher GLRs. Droplet size measurements at 100 mm downstream of the exit orifice showed reduction in Sauter mean diameter (SMD) diameter with increase in GLR. A radial variation in the SMD is observed for the blend and pure plant oils. Pure oils showed a larger variation when compared to the blend. Spray unsteadiness has been characterized based on the image-to-image variation in the mean droplet diameter and fluctuations in the spray cone angle. Results showed that pure plant oil sprays are more unsteady at lower GLRs when compared to diesel and blend. A critical GLR is identified at which the spray becomes steady. The three regimes of spray operation, namely ``steady spray,' ``pulsating spray,' and ``spray and unbroken liquid jet' are identified in the injection pressure-GLR parameter space for these pure plant oils. Two-phase flow imaging inside the exit orifice shows that for the pure plant oils, the flow is highly transient at low GLRs and the bubbly, slug, and annular two-phase flow regimes are all observed. However, at higher GLRs where the spray is steady, only the annular flow regime is observed.