INTENSIFICATION OF HEAT TRANSFER IN HEAT EXCHANGE EQUIPMENT DURING CONDENSATION OF WATER VAPOR AFTER STEAM TURBINE INSTALLATIONS IN NUCLEAR POWER.

Abstract

The determining parameter that characterizes the intensity of heat transfer in heat exchange equipment is the heat transfer coefficient, the value of which depends on the thermal resistances occurring in the corresponding equipment. Thus, in the heat exchanger-condenser of a steam turbine installation of a nuclear power station, this is the thermal resistance during heat transfer of cooling water in heat exchange tubes and during heat transfer of water vapor condensing in the intertube space. The value of the heat transfer coefficient also depends on the geometric and thermophysical characteristics of the heat heat exchange tubes, on the contamination of the cooling water, on the presence of air in the condensing vapors. According to the proposed scheme of the experimental setup of the "pipe in a pipe" type, calculations of the heat transfer coefficient were performed when using an external transparent glass pipe and an internal metal pipe, which was treated from the outside with a water-repellent coating that provides dropwise condensation of water vapor, as well as without treatment for film condensation. Contamination of the cooling water and the presence of air in the water vapor in both cases of condensation should be the same and as minimal as possible. The analysis of the results of the calculations allows us to draw the following conclusions: the change in the state of the outer surface of the heat exchange tubes increases the heat transfer coefficient during condensation of water vapor almost three times, which ensures an increase in the efficiency of heat transfer (more than 10%), and accordingly allows to reduce the working surface of the heat exchange equipment, which is especially relevant in modern conditions of operation of power equipment, when there is a need for emergency reconstruction of partially destroyed heat exchange equipment. Bibl. 11, Fig. 2.