The influence of the impeller inlet blades on the efficiency of the blower

Designing a leading edge in an radial impeller of DA200 blower, one-dimensional method was used, which assumes constant value of absolute velocity along the height of the impeller blade cm(r) = const. This method makes design calculations much easier and enables selection of the right blade angle and, at the same time, assumes the condition of ruled surface, which considerably facilitates the production of impellers with the use of a milling method. Consideration of one-dimension model of flow contributes to the occurrence of differences between the actual flow angle and blade angle, which may lead to the deterioration of the compression process. Unfortunately, distribution of velocity right before the impeller additionally influences, e.g., the confusor shape of the inlet sleeve and cap. The latter two factors may influence the efficiency of the blower as well as shift the maximum efficiency into the area of positive and negative angles of the inlet whirl. The obtained results will be presented in this study.