THE ISSUES OF THE GAS-OIL HEAT EXCHANGER FOR HEAT RECOVERY IN GAS TURBINE ENGINE LUBRICATION SYSTEM

Preheating fuel gas in the gas turbine can be carried out in recuperative heat exchangers installed in the lubricating system of gas-turbine engines, in which heat from the heated oil is passed to fuel gas. In such exchangers it is necessary to exclude the possibility of leakage and mixing of fluids and, in case of emergency, to provide emergency shutdown of the machine. To such heat exchangers belong gas-oil heat exchangers, which are made of bimetallic tubes with safe (signaling) channel. Secure channel provides automatic operation of the system in an emergency. The article describes a constructive solution of the gas-oil heat exchangers from bimetallic tubes with safe channel. Bimetallic tubes are used both smooth and finned, with different design of safe channel. Feasibility analysis of the use of smooth and finned bimetallic tubes in gas-oil heat exchangers was performed. It is shown that the bimetallic finned tubes allow increasing the compactness of the heat exchanger and reducing the weight and material cost of the tube bundle. The lack of methods of thermal calculation of heat exchangers with safe channel resulted in the setting of goals for further research, in particular the development of mathematical models, conduction of numerical studies and physical experiments.