Research On Static Strength Verification Method For Centrifugal Compressor Impeller

Centrifugal compressor is widely used as energy conversion device in areas such as the transportation, energy and chemical. Some significant accidents caused by the failure of the impellers make people realize the strength verification for impellers should be paid more attention. The complexity of structure and the variability of working condition make impeller verification a challenge for engineers. Some companies mainly committed to compressors have established their own verifying process for impellers. However, there is still no specification which is complete and recognized by most people in the machinery industry presently.This paper mainly studies on those domestic compressors’ impellers and much work has been done aim to establish a feasible and reliable analysis process and a detailed and applicable specification of impellers.The method to establish the finite element model is described in details. There is an argument whether it is essential to build a round front edge on the blade. After the calculations taken on a model with an initial blade and that with a round front edge blade, we can make sure about the necessity of the leading edge’s fillet. Mesh the same model in three densities. Compare those results and find out which way is more reasonable. Propose bilinear simplified stress-strain curves based on the real stress-strain curve. Comparison is made between the multi curve and those three bilinear curves.A new parameter for strength verification-yield area ratio is introduced. Yield area ratio refers to the ratio between the part area of having plastic strain and the total area of the impeller. First, mesh the two type impellers and make them of different element numbers. The calculation shows that the yield area ratio is not sensitive to grid. Then, comparison is taken on different shape impellers using material curves of different tangent modulus. The yield area ratio changes little under a same rated speed when tangent modulus changes beyond expectation. At the last of this paper, relationship between yield area ratio and impeller speed is summarized.