Development and performance efficiency study of birotary low-flow turbines with rotating nozzle set

. Introduction (problem statement and relevance). For further development of low-flow turbines (LFT) used, in particular, in aerial vehicles (AV), increase in their efficiency and specific power is required. This paper presents the results of experimental studies of LFT designs known as birotary with the rotating nozzle set (RNS). The main advantage of the specified turbines is provision of compactness and high efficiency of corresponding power units.

 The purpose of the study is to select new promising design schemes or arrangements of LFT with contrarotating spools and to obtain characteristics of such turbines in different operation modes.

 The methodology consists in development of models of birotary turbines (BT) and corresponding experimental units; development of the experimental study algorithm; creation of the measurement and experimental data processing procedures.

 Scientific novelty and results. The paper has considered principally new design schemes of LFT, namely the birotary turbines (BT) with the rotating nozzle set (RNS) created on the basis of turbine stages designed by the Leningrad Polytechnic Institute (LPI) intended for low-power turbines and low flow rate of the working medium. In order to conduct the experimental studies of the BT, the methods and algorithm of experimental data processing have been developed. Following the study results, recommendations were formulated, which allowed improvement of the design and increase in the efficiency of the BT.

 Practical significance. According to the data obtained, conclusions were made on prospects of development of BT for AV from the point of view of the internal EF (efficiency factor) and weight and dimensional parameters.

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