为了快速预测空冷单元内流动特性，利用经典差分法构造空冷单元离散格式，并求解初始时间内流场的数值解，组成瞬像集合，利用瞬像构造标准POD基，以此为基础建立高精度低维度的降阶外推模型，分析了在入口风速为3和5 m/s，计算时间步长为2时空冷单元内流场特性。结果表明：采用6个自由度降阶外推模型计算时间由362 s缩短为68 s，而最大误差分别为4×10 -6和2×10 -5 m/s，符合计算精度要求，验证了降阶方法的可行性和有效性。

In order to predict the flow characteristics for air-cooled condenser quickly,the classical difference method is used to construct the discrete scheme of the air-cooled condenser,and the numerical solution of the flow field in the initial time is solved to form the snapshots.The standard POD basis is constructed by the snapshots.On this basis,a high -precision and low-dimensional reduced-order extrapolation model (ROEM) is established.The presented ROEM is applied to analyze the flow field characteristics in the air-cooled unit at computation time step of 2 and under the conditions of 3 m/s and 5 m/s inlet wind speeds.The numerical computations illustrate that the calculation time of the 6 DOF reduced order extrapolation model is shortened from 362 s to 68 s,and the maximum errors are 4×10-6 m/s and 2×10-5m/s,respectively,which meets the requirement of calculation accuracy and implies the feasibility and effectiveness of the reduced-order extrapolated algorithm.Furthermore,the ROEM provides a more reliable method for real-time prediction and control of the internal flow field for the aircooled condenser of the air-cooled island.

TK124；TK264

国家自然科学基金(51706066)