基于曲面拟合的水泵水轮机全特性曲线的新变换

为了消除由于水泵水轮机全特性曲线的"S"特性所引起的单位流最和单位力矩的多值性和变换后曲线的不均匀性,实现计算机存储数据的连续性,提出了水泵水轮机全特性曲线的新变换方法.该方法引入了导叶相对开度以获得均匀分布的变换曲线,然后利用最小二乘曲面拟合法对其进行曲面拟合,给出了可连续求导的连续性拟合函数.采用此变换方法可以实现在同一过渡过程中全开到全关(或从全关到全开)的各种水力瞬变过程的计算,改善了各种导叶开度工况特别是零开度和小开度工况全特性曲面的拟合精度.

New transformation method for complete characteristic curves of reversible pump turbine based on surface fitting

A new transformation method with a variable of relative guide vane opening was developed to eliminate the multi-numerical values of unit discharge and unit moment and the sharply varied distances between the transformed curves. The transformed curves were fitted by the least square surface fitting, and the fitting functions of continuity were achieved. As a result, the curves can be transformed into series of continuity data, and the precision of the surface fitting can also be improved greatly, especially the modes of small opening and zero opening. The hydraulic transient modes in pumped storage plants can be computed at any opening without extra programs.