Experimental study of the influence of blade height on gas-dynamic characteristics of the nozzle guade vanes of a centripetal microturbine

Abstract

The gas-dynamic characteristics of the nozzle blade ring of the centripetal microturbine were obtained experimentally in the form of dependencies of the velocity coefficient, the flow angle at the outlet of the nozzle guide vane, and the flow deflection angle in the oblique section of the interblade channel on the isentropic flow velocity at the outlet of the cascade. These dependencies were found for different values of the ratio of the height of the nozzle blade rings to the throat of the interblade channels (relative height of the blades) in the range of 0.25 ... 2.15. The error limits of the parameters of the experimental characteristics were determined using the developed method for estimating the errors of indirect measurements. It turned out that the absolute error in determining the velocity coefficient does not exceed 0.015, and the flow angles – 0.5°. It has been established that in the range of 0.85…2.15 the relative height of the blades does not have a significant effect on the type of gas-dynamic characteristics, and in the region of 0.25…0.85 with a decrease in the relative height of the blades the velocity coefficient decreases by up to 0.035, and the flow angles increase by up to 3.0°. A regression dependence is proposed to determine the change in the value of the velocity coefficient