Experimental investigation of thermal and hydraulic performance of carbon nanotube reinforced polymer fins in compact heat exchanger / Mohammed Hamood Hezam Al-shameri

Faculty of Mechanical and Automotive Engineering Technology

Thesis (Master of Science) -- Universiti Malaysia Pahang – 2025

Includes bibliographical references

At the present time, the significance of fiber-reinforced polymer (FRP) material in fins-and-tube heat exchangers (HEs) has become a critical matter in the thermal industrial sector. This is primarily due to its advantages, such as its lightweight nature, ease of manufacturing, and superior resistance to environmental conditions when compared to metal materials. The utilization of fiber-reinforced polymer fins-and-tube heat exchangers has generated considerable interest among numerous researchers, given their pivotal role in various thermal engineering systems. Several factors, including fin material, number of fins, tube diameter, air velocity, and others, directly influence the performance of fin-and-tube heat exchangers. However, the use of fiber-reinforced polymer fins in fin-and-tube heat exchangers has not been thoroughly examined, highlighting the need for a comprehensive study. Additionally, there is a lack of research on optimizing processes and geometric parameters for achieving the best heat exchanger performance. Thus, the objective of this research was to design and manufacture fins using carbon nanotube-reinforced polymer material and subsequently integrate them with copper tubes to create a fully functional heat exchanger unit. Additionally, the aim was to assess the performance of the carbon nanotube-reinforced polymer fins by analyzing various geometric parameters and investigating their thermal and flow characteristics. A series of experiments were carried out to evaluate the influence of the geometric parameters and processes on the thermal-hydraulic performance between the tube bundles. The range of the parameters considered in the study were number of fins 0, 6, 8, 12 fins, tube diameter 6.5, 8, 9.5mm, inlet air flow velocity from 2.4 to 3.6 m/s, and inlet temperature 40, 60, and 80 °C. The experiments were carried out using the wind tunnel available at the Faculty of Mechanical and Automotive Engineering, UMPSA. The wind tunnel was equipped with a blower of capacity 50 W, flow straightener, test section, and measuring sensors. The compact fin-and-tube heat exchanger was created by crafting carbon nanotube reinforced polymer fins in a foundry lab, combining them with copper tubes, all through a meticulous manufacturing process. Temperature, velocity, and pressure measurements were recorded at various positions in the test section as well as before and after the test section. The experiment analysis used heat transfer coefficient, pressure drop, and thermal performance index to evaluate the thermal-hydraulic performance of carbon nanotube reinforced polymer fin heat exchangers. The major findings showed that carbon nanotube reinforced polymer fins have a positive impact on the heat transfer enhancement. However, the results of the experimental analysis revealed that increasing the number of fins from 0 to 6, 8, and 12 fins increased the convective heat transfer coefficient by 6%, 10.77%, and 17%, respectively. While the pressure drop increased by 5.8%, 7.4%, and 9% with increasing the number of fins from 0 to 6, 8, and 12 fins, respectively. In conclusion, the successful construction of a compact heat exchanger with carbon nanotube-reinforced polymer fins has been achieved. It has been determined that augmenting the number of fins is advantageous in improving heat transfer efficiency. However, it should be noted that there is a trade-off, as increasing the fin count leads to an elevated pressure drop, necessitating higher pumping power.