Novel Hydraulic and Aerodynamic Schemes of Coil Type Steam Generator: A Mathematical Model and Experimental Data

Direct-flow steam boilers of the coil type are simple structures in which rather complex processes take place. To study this area, an educational laboratory stand was designed and constructed, which simulates the operation of a boiler of a similar design. In order to optimize the intensification of heat exchange processes in the device, raise its steam capacity, and improve its efficiency, the stand contains hydraulic and aerodynamic circuits for evaluating the movement of the coolant and air flows in the boiler. The proposed mathematical model gave an idea of the nature of the movement of the coolant in a curved pipe. The model takes into account the parameters of the screw channel for a more accurate result. The model can be used to predict the movement of the coolant in such coils with varying degrees of contamination. When designing a laboratory stand, the need for automated control is taken into account. The use of a controller to regulate the rotation speed of the pump motor made it possible to create a virtual desktop with which it is possible to control, regulate, and save all parameters. The results of the first test of the hydraulic system of the stand showed that the nature of movement in the object under study is turbulent, the critical value of the Reynolds number is higher than the generally accepted one due to the occurrence of additional forces in the curved pipe, and the mathematical model can be corrected by amendments for these forces.