Special Aspects of Designing High Temperature Plate Heat Exchangers for Small Gas Turbine Engines

Abstract

An increase in the fuel efficiency of small-sized gas turbine engines can be achieved by regenerating the heat of the turbine exhaust gases. A rational layout solution in this case is a turboshaft scheme, where the effective power is generated on the shaft of a free turbine, and the turbine exhaust gases are released into the environment without doing useful work. When creating a turboshaft engine with heat recovery, the concept of developing engine family on the base of unified gas-generator was considered. The concept involves the development of a modular system, where the addition or exclusion of individual large units allows changing the type of engine at minimal cost. The article presents the layout solution of a small-sized turboshaft gas turbine engine with heat recovery, developed on the basis of a unified gas-generator and using a gearbox to transfer effective power to a propeller or a rotor. A plate heat exchanger module with a corrugated heat exchange surface for a small-sized turboshaft gas turbine engine has been designed. The heat exchange matrix was developed using a complex techniques of computer-aided design, calculation and manufacture of plate heat exchangers. Some design features of high-temperature plate heat exchangers are identified, the most important of which is the non-uniformity of temperature fields in the heat exchange matrix. Taking into account the non-uniformity of temperature fields, the heat exchanger module is a collapsible structure allowing the replacement of the heat exchange matrix and providing compensation for thermal expansion of the heat exchanger elements. The designed plate heat exchanger module for a small turboshaft gas turbine engine will be manufactured and tested on the bench