Thermal Design and Performance Prediction of a Shell Condenser for Closed-Cycle Underwater Vehicles

The shell condenser is a key component for the underwater vehicles. To study its heat transfer performance and flow characteristics and to design a more efficient structure, a mathematical model is generated to simulate condensation inside the straight and helical channels. The model combines empirical correlations and MATLAB based on an iterative algorithm. Here, quality is used as a sign of the degree of condensation. The computational model is verified by comparison of simulations and experiments. Several cases are designed to reveal the effects of the initial condition. The inlet temperature varies from 160 to 220°C and the inlet mass velocity ranges between 133 and 200 kg/m²·s. The results show that the inlet temperature and mass velocity significantly affect flow and heat transfer in the condensation process. In addition, comparisons of the straight channel and helical channel with different Dh/R indicate that the heat transfer capability of the helical channel is obviously better than that of the straight channel, and the heat transfer coefficient and total pressure drop increase with the decrease of Dh/R. This study may provide useful information for performance prediction and structure design of shell condensers, and provide a relatively universal computational model for condensation in channels.