Blades manufactured through flank and point milling will likely exhibit geometric variability. Gauging the aerodynamic repercussions of such variability, prior to manufacturing a component, is challenging enough, let alone trying to predict what the amplified impact of any in-service degradation will be. While rules of thumb that govern the tolerance band can be devised based on expected boundary layer characteristics at known regions and levels of degradation, it remains a challenge to translate these insights into quantitative bounds for manufacturing. In this work, we tackle this challenge by leveraging ideas from dimension reduction to construct low-dimensional representations of aerodynamic performance metrics. These low-dimensional models can identify a subspace which contains designs that are invariant in performance -- the inactive subspace. By sampling within this subspace, we design techniques for drafting manufacturing tolerances and for quantifying whether a scanned component should be used or scrapped. We introduce the blade envelope as a computational manufacturing guide for a blade that is also amenable to qualitative visualizations. In this paper, the first of two parts, we discuss its underlying concept and detail its computational methodology, assuming one is interested only in the single objective of ensuring that the loss of all manufactured blades remains constant. To demonstrate the utility of our ideas we devise a series of computational experiments with the Von Karman Institute's LS89 turbine blade.
翻译:通过侧翼和点磨坊制造的刀锋将可能具有几何变异性。在制造一个部件之前,将这种变异性产生的空气动力效应计数已经足够具有挑战性,更不用说试图预测任何服务性降解的放大影响会有多大了。虽然根据已知区域和降解程度的预期边界层特征,可以设计控制容忍带的拇指规则,但我们仍难以将这些洞见转化为制造的定量界限。在这项工作中,我们通过利用从尺寸缩小到构建空气动力性能指标的低维度表示法来应对这一挑战。这些低维模型可以确定一个包含性能不易变的设计的子空间 -- -- 即非活动性子空间。通过在这个子空间内取样,我们设计了设计制造容忍度和量化扫描器的技巧,以在已知区域和降解程度的预期边界层特征为基础,我们把刀片封作为也易于定性视觉化的刀片的计算制造指南。在本文的开头两部分中,我们讨论其基本概念和详细的计算方法。假设一个子空间只对确保所有制造刀片机的用途的单一目标 -- -- 也就是我们制造刀片机的实验室的实验室的计算工具。