EFFECTS OF NEEDLE LIFT AND FUEL TYPE ON CAVITATION FORMATION AND HEAT TRANSFER INSIDE DIESEL FUEL INJECTOR NOZZLE
EFFECTS OF NEEDLE LIFT AND FUEL TYPE ON CAVITATION FORMATION AND HEAT TRANSFER INSIDE DIESEL FUEL INJECTOR NOZZLE
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DOI：
10.1615/ichmt.2017.cht-7.280
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
S. Zeidi;G. Dulikravich;S. Reddy;Shadi Darvish
中科院分区：
文献类型：
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作者：
S. Zeidi;G. Dulikravich;S. Reddy;Shadi Darvish
本文利用有限元分析软件Ansys-FLUENT，对实际尺寸的柴油机喷油器喷嘴在不同边界条件下的流动进行了模拟和分析。对矩形喷管的数值计算结果与以前的实验数据进行了比较，验证了计算结果的正确性。本研究选用的Schnerr-Sauer空化模型也得到了验证。由于两方程湍流模型与实验数据吻合较好，因此选择了两方程湍流模型。为了减少计算时间，由于该喷管的对称性，只对该喷管的六分之一进行了建模。我们目前的六孔柴油喷油器喷嘴是用不同的针杆升降来建模的，包括30,100和250。综合评价了不同提针方式对质量流量、流量系数和空化长度的影响。这些数值模拟还包括三种不同的燃料，包括一种柴油和两种生物柴油。研究了这些燃料在不同升针高度和不同压差下的行为。为了比较结果，比较了不同边界条件和几种燃料类型下的流量系数、质量流量和空化区长度。还分析了内爆空化气泡中心的极端温度尖峰随时间和初始气泡大小的变化。
In the present study, the flow inside a real size Diesel fuel injector nozzle was modeled and analyzed under different boundary conditions using ANSYS-Fluent software. A validation was performed by comparing our numerical results with previous experimental data for a rectangular shape nozzle. Schnerr-Sauer cavitation model, which was selected for this study, was also validated. Two-equation turbulence model was selected since it had good agreement with experimental data. To reduce the computing time, due to symmetry of this nozzle, only one-sixth of this nozzle was modeled. Our present six-hole Diesel injector nozzle was modeled with different needle lifts including 30 , 100 and 250 . Effects of different needle lifts on mass flow rate, discharge coefficient and length of cavitation were evaluated comprehensively. Three different fuels including one Diesel fuel and two bio-Diesel fuels were also included in these numerical simulations. Behavior of these fuels was investigated for different needle lifts and pressure differences. For comparing the results, discharge coefficient, mass flow rate and length of cavitation region were compared under different boundary conditions and for several fuel types. The extreme temperature spike at the center of an imploding cavitation bubble was also analyzed as a function of time and initial bubble size.