Study Of Inducers For Low-NPSHR Pumps

Compared with common centrifugal pumps, low-NPSHR pumps have smaller NPSHR and better anti-cavitation capability. Usually, they are used in lower NPSHA conditions such as transporting fluids which are prone to boil away and the like. Thus, they are widely used in many departments such as spaceflight, petrochemical plants, thermoelectricity, fire protection and the like.One of the primary methods to improve cavitation performances of low-NPSHR pumps is to fix inducers at their inlet. Compared with other methods, inducers have these advantages such as simple configuration, ordinary manufacture and installation, low cost, all-purpose character, convenient servicing and replacing, so are more applicable to alteration of a whole suit of pumps.But most technology of low-NPSHR pumps is still in the step of groping. Although people had agreed on increasing the inlet diameter of impeller and the width of leading blade, the detailed selection of these parameters are still under investigation. As for inducer, its design theory and method are still in seeking as yet and there has been no even one monograph. Relative plants have scarcely design capability of themselves, saying nothing of a series of optimization of inducer for reference.Based on study of design theories of inducer, this paper founded a relatively consummate design calculation method of variable-pitch inducer. Its design flow and affairs that should be noticed in the course of design were expatiated by an example. And experimentations indicated that this design calculation method had achieved destined request and got excellent cavitation performances. Furthermore, numerical simulation and calculation analysis of the inner flow of inducer were done in this paper to find out its flow information, which can obtain theoretical foundations for inducer design and matching relationship of structure and energy between inducer and impeller. At last, considering parameters such as size, structure etc, a primary recommended series of variable-pitch inducers according to the proposed method was given for manufacture and farther study.