Performance Chart and Optimum Geometries of Conical Diffusers with Uniform Inlet Flow and Free Discharge

Abstract

To obtain the best performance and optimum geometries for a wide range of diffuser geometries, experiments have been performed on many conical diffusers having uniform inlet flow outside the thin inlet boundary layer and free discharge using air flow. Performance data for diffusers are represented comprehensively in a pressure recovery coefficient and effectiveness chart including optimum geometry lines. A comparison of present results with those in references related to the problems shows that there is appreciable difference among the contours of the performance charts and optimum geometry lines obtained in different investigations conducted under similar inlet and outlet conditions .the present performance chart and optimum lines give approximately average values of the results obtained by other investigators. For geometries of cone angle 2α between 6.8 and 30 degrees, the effectiveness may be expressed with a fair degree of accuracy by the relationship ηp=1-0.0415α when the area ratio is larger than 3.