Optimal Assembly Problem of Rotor Blades : A Heuristic Approach

Abstract

Consider the optimal assembly problem of assigning blades of different but known momenta to fixed positions of a rotor of circular cross section used in hydroturbine. The assembly has to be such that the resultant imbalance of the rotor after assembly is a minimum and the momenta are more or less uniformly spread over the circular section. When the number of blades and consequently the number of possible permutations is also large , the optimal assembly is difficult to obtain. A few heuristic approaches for the assembly are suggested and the statistical properties for the assembly arc studied under an appropriate data based model (for the distribution of momenta). We compare the performance of the proposed techniques with the optimal arrangement when the number of blades is small. It is also found that the imbalance arising out of the proposed assembly can be predicted with a high degree of accuracy. based only on first a few large momenta spacings when the blade momenta follow sowe standard distributions.