Research on film condensation heat transfer at the inside of spiral coil tube

Abstract

In this paper, especially considering the influence of viscous force, gravity and centrifugal force on condensation heat transfer, a theoretical model of laminar flow for film condensation heat transfer of pure steam in the spiral coil tube was presented. The solution method of film thickness and heat transfer coefficient was analyzed theoretically, the condensation heat transfer coefficient in the spiral coil tube under different steam volume flow rates was obtained. In order to verify the correctness of the new correlation, the experimental platform of film condensation heat transfer was designed and built up. Heat transfer measurements were performed for the saturated steam volume flow rate from 2.7 to 5.2 m3/min, and for the cooling water volume flow rate from 1.5 to 7.0 m3/h, and cooling tube wall temperature is 20 °C. The experimental results were compared with the calculation results of the well-known Kang's correlation and the new correlation. The relative error of results between the new correlation and the experiment is within 15%, which verifies the accuracy of the new correlation proposed in this paper. And the new correlation can be used to calculate the heat transfer coefficient of film condensation in the spiral coil tube. In addition, the experimental results show that the condensation heat transfer coefficient increase with the increasement of steam volume flow rate.