Influence of Discharge Collecting Chambers on the Efficiency of a Turbogenerator Air Ventilator

Abstract

This paper presents the results of computational-theoretical and experimental studies of a model of discharge collecting channels of a typical centrifugal fan in an air-cooled turbogenerator. An experimental test bench was created and a measurement system was developed to determine losses with different configurations of cooling air discharge channels. It was found that the original design of the turbogenerator fan’s discharge collecting chamber has low aerodynamic efficiency due to high internal losses, which reduce the technical and economic performance of the turbogenerator. One cost-effective way to increase fan performance by reducing losses is through aerodynamic optimization of the collecting chamber contours. Analysis of computational-theoretical and experimental research results of the typical fan collecting chamber design showed that the system of guide ribs has the main influence on loss levels and aerodynamic efficiency, since these ribs simultaneously provide structural rigidity and reliability while forming the flow path geometry. An optimized flow path for the collecting chamber was developed and tested without requiring changes to the overall fan housing dimensions. The improvement in aerodynamic characteristics is associated with modifying the guide rib system design through flow channel reprofiling. The optimization of the fan collecting chamber design increased useful power output by reducing aerodynamic losses in the turbogenerator’s air-cooling system. The design optimization, which ensures smooth increase in flow area with reduced positive pressure gradients in diffuser sections of the flow path, led to a relative efficiency increase of 24% while simultaneously reducing the metal consumption of the air-cooled turbogenerator centrifugal fan collecting chamber structure.