紫外光诱导纳米颗粒胶体微射流碰撞特性（英文）

Impacting dynamics of ultraviolet induced nanoparticle colloid microjet

采用流体力学模拟方法,建立了垂直非淹没射流的计算流体动力学模型,研究了在紫外光诱导纳米颗粒胶体射流中用直径D为500μm的微孔光-液耦合喷嘴进行抛光加工的冲击动力学,分析了非淹没射流条件下光-液耦合喷嘴内、外的流场分布情况及其对工件表面的喷射冲击特征,对紫外光诱导纳米颗粒胶体射流冲击动力学过程进行了理论描述。计算结果表明,在1MPa入射压力时,微孔光-液耦合喷嘴口TiO2胶体的喷射速度约为30m/s,其集束匀速喷射距离约为5mm。在此喷射距离时进行垂直喷射,在胶束与工件表面的冲击射流作用区域,其射流静压最大值分布在射流冲击作用中心,但射流动压及射流合成速度在此区域的截面分布呈"W"形状,射流动压及速度最大值出现在胶体射流束的外环直径约2mm处。

In ultraviolet induced nanoparticle colloid jet machining, the nanoparticle colloid microjet isused to effectively remove the material of the workpiece surface. A computational fluid dynamic model for verti-cal non-submerged jet is established to investigate the impacting hydrodynamics in ultraviolet induced nanoparti-cle colloid jet machining using a micro hole light-liquid coupling nozzle with an outlet diameter of 500 μm. Withthis model, the energy characteristics of fluid field and pressure distributions in the process of ultraviolet in-duced nanoparticle colloid jet machining are computed under the condition of vertical injection. Through numeri-cal investigation, the dynamic response of two-dimensional TiO2 nanoparticle colloid jet impacting on a planesurface is studied. The simulation results indicate that the injection velocity of the TiO2 colloid in the micro-liq-uid coupling nozzle is about 30 m/s when the jet pressure is 1 MPa, and the uniform bundling jet distance is a-bout 5 mm. The static pressure of the nanoparticle colloid jet in the core area is concentrated, therefore the dy-namic pressure and the velocity distribution of the synthetic velocity in the area of the impact of the colloid im-pinging jet is ＂W＂ shaped, and the maximum value is at the 2 mm diameter of the colloid jet.