Effects of structure parameters on flow and cavitation characteristics within control valve of fuel injector for modern diesel engine
Effects of structure parameters on flow and cavitation characteristics within control valve of fuel injector for modern diesel engine
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DOI：
10.1016/j.enconman.2016.07.004
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发表时间：
2016-09-15
影响因子：
10.4
通讯作者：
Wu, Xiao-Jun
中科院分区：
文献类型：
--
作者：
Wang, Chao;Li, Guo-Xiu;Wu, Xiao-Jun
穴蚀是柴油机喷油器中的一种常见现象，对喷油器内部流动有很大的影响。然而，迄今为止的研究都集中在喷嘴内的空化特性。其对控制阀开启过程中流量的影响尚不清楚。本文对调节阀内的流动和汽蚀现象进行了数值模拟研究，分析了调节阀结构参数对汽蚀现象的影响详细研究了圆角、密封锥角和出流控制孔结构对缸内流动和汽蚀特性的影响。首先从单次喷油量和喷油持续时间两个方面对三维模型进行了验证，表现出良好的一致性。然后讨论了从片状空化到云雾状空化的发展过程以及空化与压力、速度的关系。数值结果表明，不仅压力的变化是影响空化的重要因素，而且速度的变化也是影响空化的重要因素。流速的增加降低了流场内的压力，加剧了空化的发展。随着空化区域的增大，燃油流动受阻，流速降低。流速的降低抑制了空化的发展。所有这些变化形成一个循环过程。(C)2016爱思唯尔有限公司版权所有。
Cavitation is a common phenomenon in diesel injector and has a strong influence on the internal flow. However, studies so far have focused on cavitation characteristics inside the nozzle. Its influence on the flow during control valve opening remains still unclear. In the paper, a computational study focused on the flow and cavitation phenomena within control valve has been reported and the effects of control valve's structure parameters (including rounded edge, seal cone angle and outflowing control-orifice structure) on the flow and cavitation characteristics have been investigated in detail.Firstly the 3D model has been validated in terms of single injection quantity and fuel injection duration, showing a good consistency. And then, the development from sheet cavitation to cloud cavitation and the relationship between cavitation, pressure and velocity has been discussed. Based on the numerical results obtained, it is shown that not only the variation of pressure but also the velocity is the important factor which affects cavitation. The increase of the flow velocity reduces the pressure within the flow field which can aggravate the development of cavitation. As cavitation region increases, the fuel flow is hindered and the flow velocity decreases. However, the decrease of flow velocity has suppressed the development of cavitation. All of those variations form a cyclical process. (C) 2016 Elsevier Ltd. All rights reserved.