在CFD平台软件OpenFOAM上,用数值模拟的方法分析了变截面毛细流道中的毛细流动行为。该数值方法利用流体体积比函数(volume of fluid,VOF)来跟踪流体流动前沿界面,再用连续表面张力模型(continue surface force,CSF)来描述毛细驱动力。...在CFD平台软件OpenFOAM上,用数值模拟的方法分析了变截面毛细流道中的毛细流动行为。该数值方法利用流体体积比函数(volume of fluid,VOF)来跟踪流体流动前沿界面,再用连续表面张力模型(continue surface force,CSF)来描述毛细驱动力。VOF和CSF方法的结合使得毛细驱动力的求解能适应截面的变化。分别用该数值方法和解析方法对变间距平行平板间毛细流动进行了分析,发现两者的分析结果一致性较好。基于VOF和CSF的数值方法有望进一步应用于更复杂流场中的毛细流动分析。展开更多
The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-...The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-feed machine.In order to develop such a machine,3D-modeling and machine simulations were performed and a twin wheel creep-feed grinding machine was manufactured.Furthermore,the axisymmetric precision of the machined workpieces through practical machining was evaluated and the quality of the continuous dressing effect of the developed machine was established.In addition,experimental considerations for a proper dresser-to-wheel speed ratio and proper feed rate of the dresser were carried out.As a result,a twin wheel creep-feed grinding machine with continuous dressing is developed through machine simulation,manufacturing and performance evaluation.Optimum condition for the dresser feed rate is 0.3μm/rev.In cases of large dressor-to-wheel speed ratio,grinding efficiency can be enhanced,but the surface roughness shows a conflicting trend.Developed twin wheel creep-feed grinding machine has satisfactory appraisal with regard to surface roughness,flatness,and parallelism.Satisfactory surface roughness below 0.1μm can be obtained for the blade of aircraft.However,in order to perform precise machining,it is necessary to improve the structure of the twin wheel creep-feed grinding machine.展开更多
文摘在CFD平台软件OpenFOAM上,用数值模拟的方法分析了变截面毛细流道中的毛细流动行为。该数值方法利用流体体积比函数(volume of fluid,VOF)来跟踪流体流动前沿界面,再用连续表面张力模型(continue surface force,CSF)来描述毛细驱动力。VOF和CSF方法的结合使得毛细驱动力的求解能适应截面的变化。分别用该数值方法和解析方法对变间距平行平板间毛细流动进行了分析,发现两者的分析结果一致性较好。基于VOF和CSF的数值方法有望进一步应用于更复杂流场中的毛细流动分析。
基金Work supported by the Second Stage of Brain Korea 21 Project
文摘The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-feed machine.In order to develop such a machine,3D-modeling and machine simulations were performed and a twin wheel creep-feed grinding machine was manufactured.Furthermore,the axisymmetric precision of the machined workpieces through practical machining was evaluated and the quality of the continuous dressing effect of the developed machine was established.In addition,experimental considerations for a proper dresser-to-wheel speed ratio and proper feed rate of the dresser were carried out.As a result,a twin wheel creep-feed grinding machine with continuous dressing is developed through machine simulation,manufacturing and performance evaluation.Optimum condition for the dresser feed rate is 0.3μm/rev.In cases of large dressor-to-wheel speed ratio,grinding efficiency can be enhanced,but the surface roughness shows a conflicting trend.Developed twin wheel creep-feed grinding machine has satisfactory appraisal with regard to surface roughness,flatness,and parallelism.Satisfactory surface roughness below 0.1μm can be obtained for the blade of aircraft.However,in order to perform precise machining,it is necessary to improve the structure of the twin wheel creep-feed grinding machine.
