Enhanced filmwise condensation of ethanol

• Main Author: Wong, Nicole Hui Shi
• Other Authors: Ho Jin Yao
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/167199
• Institution: Nanyang Technological University

This report presents a study on the enhancement of filmwise condensation of ethanol. The objective of the research is to improve the thermal efficiency of condenser tubes using novel geometrical design with the aim of implementing them in industrial heat exchangers. Experiments were carried out to assess the heat transfer performance of ethanol during condensation on specially designed 3D-printed tubes, i.e., Designs 1, 3, 4 and 5. An experimental setup that was developed consists of a vacuum chamber to conduct the experiment with pure vapor and under steady-state conditions. The test was carried out at a steady pressure with varying flow rates of water as the cooling fluid flowed through the internal channel of the tube. The results show that Design 4, with outward curvatures and a sharp edge at the bottom, exhibited the highest condensation heat transfer coefficient, with a 75% enhancement percentage compared to the conventional circular tube. Moreover, in comparison to Design 3 and Design 1, which consists of inward curvatures and rounded tip at the bottom, Design 4 shows a 72% and 112% increase in condensation heat transfer coefficient performance respectively. However, further investigation was conducted to evaluate the uncertainty in this experiment, revealing other factors that may have impacted the accuracy and reliability of the results. In this study, the main chamber pressure was set at 35 kPa as it was found by the preceding student to be safe to operate, the results were repeatable and reliable, thereby establishing it as the optimum pressure for data collection and calculation. The specifically designed tubes facilitated the flow of condensate away from the surface, enhancing the rate of condensation heat transfer.