Experimental study of a bidirectional impulse turbine in a steady gas flow

Background and Objectives: The bidirectional impulse turbine can be used to generate electricity from the energy of sea waves or to convert acoustic energy into electrical energy in thermoacoustic generators. Materials and Methods: In this paper, an experimental study of the characteristics of a bidirectional turbine in a constant gas flow was carried out. The experiments were carried out with a fixed and freely rotating turbine rotor. The outer diameter of the turbine blades is 44 mm. The average gas velocity at the turbine inlet was measured using a Venturi tube and an anemometer. Measurements were made for the dependence of the pressure drop across the nozzles and the turbine rotor on the cross-sectional mean gas velocity at the turbine inlet. Results: It is shown that with an increase in the rotor speed, the pressure drop across the inlet nozzle apparatus decreases, while on the rotor and the outlet nozzle apparatus it increases. The proportion of the parasitic pressure drop at the outlet nozzle apparatus in the pressure drop across the entire turbine increases with an increase in the rotor speed. At a rotor speed of 7000 rpm, the parasitic pressure drop was 15% of the pressure drop across the entire turbine. It was shown that in a constant gas flow, the investigated turbine has a degree of reaction from 0.61 to 0.84.