Heat transfer characteristics of steam condensation flow in vacuum horizontal tube

Abstract

The heat transfer characteristics of steam condensation flow in a vacuum horizontal long tube were studied experimentally when the saturation temperature varies from 50 to 70°C,mass flow rate is no more than 11 kg/(m 2 •s) and temperature differences between steam and cooling water are 3, 5 and7°C respectively. The results of experiments indicate that the steam temperature decreasesand the condensation temperature difference decreases first and then increases along the flow direction. The effects of mass flow rate and total temperature difference on temperature distribution are also discussed in the paper. The condensation heat transfer coefficient increases first and then decreases along the flow direction. The heat transfer coefficient increases with mass flow rate in most cases, but may decrease in the first section at high mass flow rate. The heat transfer coefficient also increases with saturation temperature and decreases with condensation temperature difference. The heat transfer rate decreases along the flow direction and increases with mass flow rate.

Numerical study of steam condensation inside a long, inclined, smooth tube at different saturation temperatures

“…shows the comparison between the present numerical results and the experimental data of Wang et al[17]. The presented results are for the horizontal tube at the operating condition of G = 6.6 kg/m 2 s, and at the two saturation temperatures of 50°C and 70°C.…”

“…3. Comparison between the numerical results of this study and the experimental data from Wang et al [17] for the condensation heat transfer coefficient along the horizontal tube. Fig.…”

“…Wang et al [17] investigated the steam condensation inside a long, 8 m, horizontal smooth tube. They studied the effects of saturation temperature, steam mass flow rate, and temperature differences, between steam and cooling water on the condensation 7 heat transfer coefficient.…”

“…The computational domain was an 18-mm inner diameter circular smooth tube with a length of 7200 mm. The tube has already been used by Wang et al[17] for the experimental study of steam condensation. The following boundary conditions were assumed for all the simulations:1.…”

“…The presented results are for the horizontal tube at the operating condition of G = 6.6 kg/m 2 s, and at the two saturation temperatures of 50°C and 70°C. In this case, the imposed negative heat flux on the tube wall varied from 400 W/m to 700 W/m along the length of the tube[17]. The tube was divided into four sections, and the reported values for the heat transfer coefficients were the average values of each section.…”