Experimental and numerical investigation of flow forces in a seat valve using a damping sleeve with orifices

Abstract

The power of hydraulic piston engines is much affected by the on-off valves which control the fuel injection of the piston assembly. Therefore, the opening time of the seat valve used as the on-off valve is optimized by minimizing the axial flow forces on the spool. A damping sleeve with orifices is proposed to change the valve internal geometry. Experimental and numerical investigations of the flow forces acting on the spool with and without the proposed damping sleeve are carried out to identify the differences in the flow field and to minimize the forces’ effect. The simulated results fit the experimental results well. Both results show that the proposed damping sleeve affects the pressure distribution along the spool cone surface and the jet stream direction significantly. The effects of the orifice’s width, height, and relative sleeve installation positions on the flow field and cavitation are assessed using simulation methods. As a result of the flow field changing, the damping sleeve can reduce the flow forces significantly and even reverse the forces’ direction at the cost of a little flow loss. The opening time of the seat valve can be reduced by 31% to 0.67 ms by using the proposed damping sleeve.

中文概要

目的

液压自由活塞发动机性能受燃油喷射系统开关阀性能限制。本文旨在对开关阀内部结构进行优化,降低液动力,从而提高阀的开启速度。

创新点

1. 提出一种易于安装的带孔阻尼套结构,可以用于改变阀芯表面压力分布和油液射流角,从而降低液动力;2. 建立数值仿真模型,分析阻尼套不同结构和安装参数对液动力和空化的影响。

方法

1. 进行数值模拟,分析阀芯表面压力分布和内部流场分布,并通过实验验证方法有效性和模型准确性;2. 对不同阻尼孔宽度、深度和相对位置下的阀芯液动力和流量损失情况进行对比和分析;3. 对上述不同阻尼孔结构下阀内空化情况进行仿真和对比;4. 建立燃油喷射系统试验台,验证阻尼套对提高阀开启速度的作用。

结论

1. 提出的带孔阻尼套结构可以有效降低阀芯液动力。2. 随阻尼孔的减小,其对液动力的改变作用和节流作用逐渐增强;阻尼孔足够小时液动力反向并逐渐加强。3. 阻尼套对油液的阻碍作用也会改变流场内的空化情况,但空化强度不一定随节流孔的变大而单调变强,其还受相对安装位置影响。4. 带孔阻尼套可以有效降低阀的开启时间。