Theoretical foundations of increasing the efficiency of wide-angle diffusers and practical results of new solutions to this problem

Abstract

It is shown theoretically that the efficiency of wide-angle diffusers mainly depends on the method of supplying the working medium to the diffuser channel and on the nature of the interaction of this medium with the subsequent streamlined surface of the diffuser. The first condition is due to those changes in the acting force factors within the wall (boundary layer), which occur during the transition from the inlet confuser channel to the subsequent diffuser, and the second follows from the need to ensure an uninterrupted flow of the working medium moving against the increasing (in the direction of travel) static pressure. The above computational studies of wide-angle diffusers have shown that, subject to theoretically justified conditions, it is possible to ensure uninterrupted flow in flat and conical diffusers with an increase in the opening angle α of their flow path to 20° and with the same degrees of expansion ration to obtain pressure recovery coefficients commensurate with those in diffusers with an angle α = 7°.

Methods for increasing the energy efficiency of fan systems using wide-angle plane diffusers with splitter vanes

“…In [20], the authors perform a theoretical study of flat and conical diffusers proving that, for the case of theoretically justified conditions, that it is possible to ensure a flow without separation at angles up to 20 degrees and static pressure-recovery coefficient, which corresponds to a diffuser with an angle of 7 degrees.…”