Biofuels ( IF 2.1 ) Pub Date : 2019-11-27 , DOI: 10.1080/17597269.2019.1693180 Joanne Lim 1 , N.A. Razak 1 , Nurul Musfirah Mazlan 1
Abstract
Spray characteristics and transient behaviour of alternative fuel droplets at different spray cone angles, injection pressures and droplet diameters are presented, using a simple spray evaporation model. The model only considers drag force acting on the droplet. Radiation heat transfer during the evaporation process is neglected. The model incorporates temperature-dependent fuel properties, drag coefficient and Reynolds number for robustness. It is tested for alternative fuels, namely Jatropha Bio-synthetic Paraffinic Kerosen (JSPK), Camelina Bio-synthetic Paraffinic Kerosene (CSPK) and biodiesel, while Jet-A is used for comparison. The transient behaviour of fuel droplets is visualised through a time-history of the normalised squared diameter. Changes in the particles’ temperature, mass, density, velocity and heat transfer coefficient over time are observed. Moreover, penetration of the fuels at different spray cone angles, injection pressures and droplet diameters is compared. Among the tested fuels, biodiesel is found to have the farthest penetration due to its high vapour pressure. Notably, increasing spray cone angle reduces penetration length. A similar trend is observed when injection pressure is increased. However, at constant injection pressure, increasing droplet diameter increases spray cone angle and spray penetration. To obtain optimum penetration, therefore, a larger cone angle should be used for fuel with high density and vapour pressure, and vice versa.
中文翻译:
使用简单蒸发模型评估替代燃料在不同喷雾锥角和喷射压力下的喷雾穿透力
摘要
使用简单的喷雾蒸发模型,介绍了替代燃料液滴在不同喷雾锥角、喷射压力和液滴直径下的喷雾特性和瞬态行为。该模型仅考虑作用在液滴上的阻力。蒸发过程中的辐射传热被忽略。该模型结合了与温度相关的燃料特性、阻力系数和雷诺数,以提高鲁棒性。它测试了替代燃料,即麻风树生物合成石蜡煤油 (JSPK)、Camelina 生物合成石蜡煤油 (CSPK) 和生物柴油,而 Jet-A 用于比较。燃料液滴的瞬态行为通过归一化平方直径的时间历程可视化。粒子温度、质量、密度的变化,观察随时间变化的速度和传热系数。此外,比较了燃料在不同喷射锥角、喷射压力和液滴直径下的渗透。在测试的燃料中,发现生物柴油由于其高蒸气压而具有最远的渗透。值得注意的是,增加喷雾锥角会减少穿透长度。当注射压力增加时观察到类似的趋势。然而,在恒定的喷射压力下,增加液滴直径会增加喷雾锥角和喷雾穿透力。因此,为了获得最佳渗透,对于高密度和蒸汽压的燃料,应使用较大的锥角,反之亦然。由于蒸汽压高,生物柴油被发现具有最远的渗透。值得注意的是,增加喷雾锥角会减少穿透长度。当注射压力增加时观察到类似的趋势。然而,在恒定的喷射压力下,增加液滴直径会增加喷雾锥角和喷雾穿透力。因此,为了获得最佳渗透,对于高密度和蒸汽压的燃料,应使用较大的锥角,反之亦然。由于蒸汽压高,生物柴油被发现具有最远的渗透。值得注意的是,增加喷雾锥角会减少穿透长度。当注射压力增加时观察到类似的趋势。然而,在恒定的喷射压力下,增加液滴直径会增加喷雾锥角和喷雾穿透力。因此,为了获得最佳渗透,对于高密度和蒸汽压的燃料,应使用较大的锥角,反之亦然。