Авіаційно-космічна техніка та технологія (Aug 2020)
INVESTIGATE OF TURBINE PART AND COMPRESSOR PART OF TURBO-COMPRESSORS WITH GENERAL IMPELLER FOR ENGINES AND POWER PLANTS
Abstract
To develop engines and power plants, the issues of improving engines through the use of a new type of turbomachines – turbo-compressors with general impeller (TCG) have been considered. There is another name for this type of turbomachine – a single-disk turbo-compressor (STC), although for bladed machines it is not the disk that is important, but the entire impeller. For example, a diagram of the simplest small-sized gas turbine engine using TCG is shown. For the systematization of relatively efficient TCG schemes, a classification has been developed and is given in the article, of possible schemes for a turbocharger with a common impeller. To implement one or another flowing pattern in the impeller, it is necessary to select the appropriate shape of the impeller blades and the location of the nozzle, exhaust, suction and discharge channels relative to each other. Depending on the direction of movement of the gas flows, turbo-compressors with a common impeller may have two flow patterns in interscapular impeller space – direct-flow and counter-flow. If the directions of the gas and airflow coincide to the axis of rotation of the impeller, then the flow pattern in the TCG is direct-flow, with opposite flow flows it is countercurrent. For carrying out the enlarged gas-dynamic calculation of TCG, formulas are given that make it possible to calculate the circumferential force arising on the blades of the impeller in the compressor and turbine working channels of the TCG. Also, formulas are given, with correction factors, for calculating the power factor of the compressor part and the load factor of the turbine part. In the process of computational and experimental studies, the characteristic of the compressor part of the TCG experimental model was obtained. If the ratio of the grating width to the average diameter of the working channel is overestimated, it is necessary to supplement the formula for calculating the compressor power factor with a correction factor. The test results of the compressor part of the TCG experimental model showed good agreement between the calculated and experimental values. Studies have shown that a turbocharger with a common impeller can be used as of gas turbine engines and in a turbo-supercharging system of a capacity internal combustion engine with not high supercharging.
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