针对某船用2.5 MW汽轮机组调节阀门在小开度运行下的非定常气动特性，采用延迟分离涡模拟（DDES）开展了全三维数值模拟。重点评估了阀座表面安装导流凸台对该阀门的阀碟气动力波动和扩压管内非定常蒸汽流场的影响。研究表明：在阀门喉部上游阀座处安装导流凸台后，阀门内部的主要流态从壁面分离流动转变为壁面附着流动，有效降低了阀门内的压力脉动幅值；安装导流凸台可以显著降低阀碟在轴向及侧向上的气动力波动幅值，轴向气动力波动幅值降低约51%，侧向气动力波动降低约34%。

To obtain the unsteady aerodynamic characteristics of the control valve in a 2.5 MW marine steam turbine under small opening condition,threedimensional numerical simulation was carried out by using delayed detachededdy simulation (DDES).The influences of flow guiders installed on the valve seat surface on aerodynamic force fluctuation at valve disc and unsteady steam flow field in diffuser were analyzed emphasisly.Results show that the main flow pattern inside the valve changes from walldetached flow into wallattached flow after adding flow guiders on the valve seat which lies upstream of the valve throat and the pressure fluctuation amplitude in the valve reduces effectively.The fluctuation amplitude of the axial and lateral aerodynamic force on the new valve disc can be significantly reduced by installing flow guiders.The rootmeansquare (RMS) value of the axial aerodynamic force fluctuation is reduced by about 51%,and the lateral one is reduced by about 34%.

TM62

国家自然科学基金（11802177）