Конверсия авиационного турбореактивного двухконтурного двигателя в установку для выработки пиковой электроэнергии

Abstract

The paper is aimed at considering the aircraft engine conversion into peak or short-used energy unit, which is relevant for the task of developing the northern regions of the Russian Federation. The three-shaft turbojet engine with a twelve-stage compressor and a four-stage turbine is adopted as an aircraft engine under consideration. The afterburner with a block of jet nozzles is removed from the gas generator module, and a heating chamber is set at the outlet of the by-pass duct to raise electric power of engine and not complicate the construction by the presence of a mixing chamber. In addition, the heating chamber serves to equalize the total pressure and flow temperature in the section before the free turbine and allows the use of a short adapter between the gas generator module and the free turbine, which reduces the loss of total pressure. Then a free turbine and a diffuser with an exhaust device are installed. The output shaft of the power turbine is connected by means of a coupling to an alternating current (a. c.) generator or other special load. To find the parameters of the plant, a calculation was made in which the initial data were taken, namely a gas temperature in front of the turbine of 1530 K (the gas temperature in front of the turbine is reduced by 100 K in order to prolong the engine life; therefore, the gas temperature before the turbine was 1630 K); air flow of 364 kg/s; bypass ratio of 1.36 (the ratio of the air flow passing through the bypass duct to the air flow entering the core). As a result, it consumes 0.296 kg / (kWh) (fuel-aviation kerosene) and a power capacity of 78.5 MW. For the received value of capacity the ТЗФП-80-2У3 a. c. electric generator has been chosen as the load. As a result, the power plant, equipped with a converted engine and electric generator, has an electric power of 77.3 MW and an efficiency of 27.8%. To assess the effect of introduced preheating chamber on the parameters of the gas turbine engine, a calculation was performed with no heating chamber, and it was obtained that the introduction of a heating chamber in the bypass duct to heat the bypass duct airflow from 402 K to 967 K, reduces the engine efficiency by 2%, but increases its power by 79% - from 43.8 MW to 78.5 MW. Due to the sufficiently high gas temperature, the converted engine has a relatively short lifetime. On the contrary, the free turbine has a longer life, and therefore there is no need to manufacture a free turbine for each converted engine. For an approximate evaluation of the free turbine life before the overhaul of the engine hot section, the maximum stress at the root of the working blade was calculated. For temperature values of 1000 K and stress of 242 MPa it is possible to create a turbine with a lifetime of over 30,000 hours.