Geometric characteristics of the pipe in pipe type device with a screw heat exchange element

Abstract

To increase the thermal and hydrodynamic efficiency of tubular apparatuses, it is necessary to develop new designs of heat-exchange elements, which are distinguished by high thermal efficiency, manufacturability and low cost of production. In the work, it is proposed to use screw pipes as heat-exchange elements of tubular heat exchangers, since they have a higher degree of surface development compared to smooth-tube elements. The manufacturing technology of such pipes can be carried out in the cold state by the method of rotational forging (rotational compression), which is one of the varieties of the forging process and implemented on special rotary forging machines. To determine the heat transfer coefficients in the screw heat exchange elements mounted a special experimental setup. The main part of the installation is a pipe-in-pipe type heat exchanger, the heat exchange element of which is made in the form of a screw pipe. A experimental research technique has been developed, and the results of physical experiments on heat transfer, as is known, are generalized by criterion equations in which an equivalent diameter is used as a characteristic size. In this regard, the authors proposed a method for calculating the basic geometric characteristics of a screw heat-exchange element, and also obtained formulas for calculating the equivalent diameter of the pipe and annular space in a tube-in-pipe apparatus with a screw heat-exchange element. The results of this work can be used in the calculations and design of new promising heat exchange equipment.