异型分压阀口节流槽节流特性研究

Studies on the Throttling Performance of Non-circumferential Throttling Port

异型分压节流槽在分散节流阀口压降集中,减小阀口空化剧烈程度方面具有非常重要的意义。通过分析U型和V型分压节流阀口各自通流截面的水力直径D h,得出了U型节流槽和V型节流槽通流能力方面的差异。通过两种节流槽节流特性的研究发现:对于U型节流槽,当处于较大阀口开度时,其通流能力受到限制,会出现通流性能饱和现象;而对于V型节流槽,其水力直径D h与阀口开度X具有较好线性关系,并且其流量可控性要好于U型节流槽。另外从异型节流阀口的特点出发,推导了适用于分压节流阀口的空化特性计算公式,并在此基础上发现当阀口体积流量Q方向相反时,在阀口过流截面上的空化特性是有差异的;当液流体积流量Q从较大过流截面A1流向相对较小的过流截面A2时,在节流主要截面A2附近的空化指数σ要明显大于当体积流量翻转时在A2附近的空化指数;并从理论上解释了该现象的产生原因。

Relative to circular throttling port, partial pressure throttling groove is significant for releasing pressure drop contraction in throttling port, and decreasing cavitation probability. For typical non-circumferential throttling ports U groove and V groove, their flow abilities（hydraulic diameters） were studied, and it was observed that for U groove, the flow ability is limited under a larger opening, as actual flow ability is depend on minor hydraulic diameter and it is a fixed value; for V groove, hydraulic diameters has a good linear relationship with port opening that means V groove has a wider flow range than U groove does, in other words, V groove is easier to obtain stable smaller flow rate; based on classic cavitation index, new-form cavitation index calculation formula, which is applicable to partial pressure throttling port, was deduced, and the cavitation indexes of U groove and V groove were calculated respectively, and it was found that whether U or V groove, for different flow directions cavitation indexes are different; when fluid flows from the larger section AI to section As cavitation index near section A2 is remarkly larger than that when fluid reversal. At last, this phenomena was theoretically explained.