The Nozzle Guide Vane Problem

Abstract

The nozzle guide vane problem addresses the issue of maximizing the number of aircraft gas turbine engine nozzles that can be assembled, within strict specifications, from an inventory of nozzle guide vanes. Past research efforts have decomposed this problem into two related problems: (1) the assignment of nozzle guide vanes in inventory to a nozzle, and (2) the uniform sequencing of the vanes that have been assigned to a nozzle. Both of these problems have been shown to be NP-hard. Consequently, to obtain an efficient system that may be used effectively in a real-time manufacturing environment, we developed heuristic procedures and showed them to be effective in solving these problems. We describe the nozzle guide vane problem in detail and trace some of the developments in measurement technology that fostered the realization of the problem and facilitated the use of operations research techniques to solve it. We then develop a procedure for the uniform sequencing of a heterogeneous set of vanes within a nozzle. Empirically, the procedure is shown to be effective and requires a computational effort that is acceptable for practical implementation in a real-time manufacturing environment. This procedure, combined with those from past research, has been designed into a system that has been successfully implemented in practice. We use an actual vane inventory to demonstrate the use of the system, and discuss some short term benefits and expected long term benefits that have been and may be realized through the use of the system.