P32-07 超小型ガスタービン用ラジアルタービンの要素研究

概要

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Small-scale radial gas turbines that are composed of a two-dimensional vaned nozzle and a two-dimensional impeller with tip diameter of 40 mm have been designed and fabricated. The designed pressure ratio, mass flow rate, and turbine inlet temperature are, respectively 2.9,30 g/s and 1223K. These turbines are expected to generate an output power approximately of 7 kW at a rotational speed of 2.4×(10)^5 rpm. Preliminary aerodynamic-performance measurements indicated a maximum adiabatic-efficiency of over 75% on the total-to-static basis, which is about 10% lower than that of a conventional three-dimensional radial turbine. In order to improve their aerodynamic performance, the internal flows of the two-dimensional turbines have been investigated in detail by using the three-dimensional Navier-Stokes computations with Baldwin-Lomax turbulence model. From the results of the computations, two major sources have been identified to be primarily responsible for the generation of loss, and therefore they give room for performance improvement : a large-scale separation that takes place at the inlet of the exducer due to the abrupt change in exit flow-angle and a separation that is likely to take place on the suction side of the blade aft passage due to relatively small flow acceleration.
社団法人日本機械学会の論文
2002-06-14