An evaluation of a design method for mixed flow fans

[摘要] ENGLISH ABSTRACT:Mixed flow fans find application in an operating region between that of axial flow andcentrifugal fans. The candidate investigated the working of these mixed flow fans andformulated a design algorithm. The algorithm was based on work done by previous authors,most of which have tried to modify existing axial flow fan design methods to suit the mixedflow case. A fan was designed, built and tested. Tests showed that the fan did not perform asdesigned, producing a lower pressure rise at a lower flow rate. A five hole probe was used tomeasure the exit flow vector and the results showed that most of the work was done by thelower half of the blade. Based on this discrepancy between the designed and actual fanperformance, a number of changes to the design procedure were recommended. Amongstother things: the use of numerical blade modelling procedures instead of modified cascadecorrelations and the disregard of the Coriolis work in the design of the blade shape.

[发布机构] Stellenbosch University