APPLICATION OF A LOCAL APPROACH FOR EVALUATING TRANSFER PROCESSES IN THERMAL POWER EQUIPMENT

Abstract

It is known that, as a rule, heat carrier flows in the flow path of thermal power equipment are significantly turbulized due to many disturbing factors (increased turbulence, velocity unsteadiness, pressure gradients, local closed separations, etc.). The results of comprehensive studies of transfer processes under complex conditions of interaction between external (increased turbulence) and internal (separation) turbulence effects, typical for heat and power equipment, make it possible to develop measures to improve the thermal efficiency of working surfaces and the coolant supply system. The object of this study is the heat exchange surfaces of power, chemical and electronic equipment, as well as coolant supply systems for the development of energy efficient heat technologies. The purpose of the work is to develop methods for evaluating the transfer processes in thermal power equipment based on local control of thermophysical parameters in characteristic zones of the working environment. Research method - physical modeling of turbulent effects of different nature and processes of heat, momentum and mass transfer using hot-wire, electrocalorimetric measurement methods and thermal mass analogy methods. The studies were carried out in specially made experimental samples of installations that completely reproduce the operating conditions of a full-scale installation in terms of geometric parameters and coolant supply system. The advantage of the work is the local approach, which allows fixing thermophysical parameters in a characteristic zone of the working space. The use of this approach makes it possible to control the most dangerous heat-stressed areas and takes into account the spatial non-uniformity of the temperature field, which is the basis for developing measures to improve the thermal efficiency of working surfaces. The paper considers a generalized study of the local approach application on the examples of assessing the impact of increased turbulence, local closed separations, flow with periodic nonstationarity on the transfer processes in the flow part of heat and power equipment, as well as for developing an effective coolant supply system for the final drying of plant materials.