CHOICE OF THE PARAMETERS OF TWISTED TAPES FOR HEAT TRANSFER INTENSIFICATION IN THE CHANNELS OF THE POWER EQUIPMENT COOLING SYSTEM

Abstract

The paper presents the results of analyzing the efficiency of heat removal processes in the channels of the power equipment cooling system. The processes of heat transfer in the ventilation ducts of the cooling system for traction motors of diesel locomotive power plants are considered. The feasibility of using artificial intensification of heat transfer processes in the ducts with the help of spiral tapes is analyzed. Convective heat transfer intensifiers of this type are characterized by a significant increase in heat transfer coefficients, ease of manufacture, and low material consumption. Such devices can be used both in the design of new units and in the modernization of existing heat exchange equipment. The efficiency of intensification of heat transfer processes was evaluated by the level of reduction in the power of cooling system fans. The estimates were made assuming the same heat transfer coefficients in the channels with spiral strip inserts and in the channels without inserts. The length of the spiral tapes and the channel is the same. The effect of finning of the channel surface by the inserts was not taken into account. Known criterion equations were used to calculate the convective heat transfer coefficients and hydraulic resistance. It is shown that, despite the increase in hydraulic resistance coefficients and pressure losses in the channels of the air cooling system, the use of spiral tapes due to a noticeable decrease in the speed and, consequently, the cooling air consumption provides a reduction in fan power in a wide range of geometric parameters of spiral tapes while ensuring the required temperatures of equipment elements. The influence of the temperature of the walls of the cooling system channel on the required fan power when using artificial heat transfer intensifiers in the form of spiral tapes is estimated. Recommendations for the selection of geometric characteristics of spiral tapes are proposed, at which, taking into account the values of the channel wall temperature, a decrease in the power of the cooling system fans should be expected.