Date of Graduation
Statler College of Engineering and Mineral Resources
Mechanical and Aerospace Engineering
This research aims at designing a shell and tube heat exchanger which will drive a turbine operated on supercritical CO2. Hot gases from boiler (simulated using air) at 1500 K is introduced into the shell to heat up the supercritical CO2 at 10 MPa flowing within tubes from 450 K to 1050 K. The design was done using selected shell and tube heat exchanger empirical equations at predefined boundary conditions. The effect of shell and tube diameter on other design parameters was examined. It was observed that the number of tubes, tube external and internal side surface area, volumes of shell and tube, overall surface area and mass of tube material increases as the shell diameter increases from 6 m to 18 m at 2 m interval and this is due to the increase in cross sectional area. The shell length, the number of baffles, overall heat transfer coefficient, the pressure drop in both shell and tube sides all decreases as shell diameter increases at same rate as described previously, and this is attributed to a reduced velocity caused by the increased cross section area of tubes and baffle space. The increase in tube diameter from 0.0092 m to 0.12 m at 0.02 m intervals however leads to an increase in shell length, volume of tube material, number of baffles, shell side pressure drop, tube side pressure drop, overall area of the device ,tube external side surface area and tube internal side surface area. However, the overall heat transfer coefficient, total length of tubes and number of tubes decreases as the tube diameter increases at same rate as described previously. A decision was made on the selected heat exchanger based on fewer tubes, reduced mass of tube materials , low shell and tube pressure drop, and a high heat transfer coefficient. A selected of shell diameter 8 m, shell length 51.62 m, tube diameter 0.102 m, number of tubes 1509 and overall heat transfer coefficient 60.51 W/m2K was considered.
A CFD analysis was conducted using ANSYS 18.1 on the prototype of the selected heat exchanger device. The device was built using the design modeler and it consist of the shell, tubes, air fluid, CO2 fluid and baffles The meshing and naming of unit parts was done while the set-up stage was achieved with the predefined boundary conditions and properties. The temperature distribution and thermal analysis of the heat exchanger was reported.
Adenuga, Kehinde Oluwatobi, "Design of a Heat Exchanger for a Supercritical CO2 Turbine System" (2021). Graduate Theses, Dissertations, and Problem Reports. 8151.