Development of technology and equipment for profiling of corrugated and ribbed tubes and creation of high-performance heat exchangers

The work is aimed at creation of high-efficiency heat regenerators of gas turbine units (GTU) of the gas transportation system of Ukraine. It is proposed to use highly effective heat exchange surfaces from the tubes of the spiral corrugated profile with high heat and aerodynamic characteristics for heat regenerators GTU, which will ensure a reduction of mass-dimensions by 30- 40% in comparison with heat exchangers made of smooth round tubes and an increase in the KPD GTU from 18-25% to 38-41%. The overall effect of using the development can be up to 25 - 30% of the gas savings used in the gas turbine for pumping. Also, by replacing the round brass tubes with spiral corrugated brass tubes with a diameter of 16 1 mm, lengths of 2 and 4 m, the heat exchangers can be upgraded, which are used in heating and hot water supply systems for buildings of various purposes. In the prototypes of heat exchangers, where the profile tubes are installed, the
heat transfer coefficient increases by 30-50%.
For the manufacture of such tubes, technology and equipment for their metal forming based on the roller spinning process have been developed. Numerical modeling and experimental studies have established the necessary parameters of profiled tubes: the depth h = 1,0-1,5 mm and the step of screw grooves t = 8 ... 12 mm. It is established that such parameters provide cross-border turbulence of a single-phase heat carrier and an increase in heat transfer of about 1.5 times. Since in order to achieve high efficiency of heat exchange it is necessary to artificially turbulize the near-wall layer with a thickness of up to 5% of the tube radius. A model of the heat exchanger is made, consisting of corrugated spiral brass tubes with a pitch of screw grooves of t = 8 mm and a depth of h = 1.0 mm. Spiral corrugated tubes were manufactured using the roller spinning process using a loose material that was poured into the tubes to increase their rigidity.