Comprehensive study of heat transfer during steam condensation

Peter the Great St. Petersburg Polytechnic University, 195251, 29 Politekhnicheskaya st., Saint Petersburg, Russia

^* Corresponding author: zajnullina_er@spbstu.ru

Abstract

This paper presents an experimental study of condensing heat transfer by a complex method that combines the capabilities of gradient heatmetry, temperature measurement, and condensate flow visualization. The experiments carried out during the saturated steam condensation at atmospheric pressure on the cooled outer surface of a vertical tube made of stainless steel. The local heat flux per unit area was measured using a gradient heat flux sensor and calculated using the equation of stationary heat conduction from temperature measurements through a cylindrical wall, the discrepancy between the results did not exceed 11%. The local heat flux ranged from 91 to 152 kW/m² depending on the distance to the upper cut of the tube. The relative uncertainty of the local heat flux measured by the gradient heat flux sensor did not exceed 6%, the relative uncertainty of the values calculated from the readings of thermocouples was about 14.5%. The combined use of gradient heatmetry and temperature measurements made it possible to calculate local heat transfer coefficients with a relative uncertainty of less than 8%. The use of condensate flow visualization revealed different modes of condensate flow over the vertical tube surface.