ДОСЛІДЖЕННЯ ВПЛИВУ ПОЛОЖЕННЯ ТРУБКИ В ПУЧКУ ТРУБ КОЖУХОТРУБЧАСТОГО ТЕПЛООБМІННИКА НА ПРОЦЕС ТЕПЛОВІДДАЧІ

Abstract

The paper is concerned with an issue of liquid distribution in the diametrical bank tubes of the shell and tube heat exchanger. The experimental-theoretical approach for the research has been applied. The data on the determination of velocities of the heated liquid through the pipes of the heat exchanger have been obtained and processed. The research was carried out at the created experimental factory. Water at a temperature of 20 ºС has been supplied to the tubes. The temperature of the water has been maintained by a thermostat. The temperature at the outlet of the tube has been measured with a thermocouple element. Water (heat conductor,) at a temperature of 60, 80 or 95 ºС has been circulating in the outside of tubes space. The temperature of the water has been maintained by pumping it through a thermostat. The velocities of the heated liquid in the diametric bank tubes have been determined, which differed considerably depending on the position of the tube. Consequently, the results of the research obtained have discovered the significant deviations of such parameters as the liquid temperature at the outlet of the apparatus, tube wall temperature and heat transfer coefficients between the tube and heated liquid. The distribution insert has been used, in order to match the above-mentioned indicators. The distribution insert is a disk with the optimized holes. The alignment of the liquid velocities through the tubes of the diametric bank has been observed, which has consequently led to the uniform heating of both the central and side tubes. The study outcome has proven to be the solution to prevent the overheating of the peripheral tubes. Thus, the generation of a uniform field of velocities for the heat transfer agent through the tubes of the shell and tube heat exchanger contributes to the uniform heating of both central and peripheral tubes, and increases the heat transfer coefficient in the side tubes. The conclusion has been drawn that the reason for the failure or heat transfer low efficiency in the peripheral tubes of the shell and tube heat exchanger is the nonuniform distribution of liquid velocities in different tubes and as a consequence, the low heat transfer coefficient in those tubes where the velocity is low.