MODELING AND SIMULATION OF CONVECTIVE HEAT TRANSFER CAUSED BY A ROTATING DISK
thesisposted on 05.03.2020, 19:24 by David Ruiz PerezDavid Ruiz Perez
Convective heat transfer due to the rotation of a submerged disk has applications ranging from the design of disk brakes, turbomachinery, and the wheels of a train. Within this study, computational fluid dynamics (CFD) software is utilized to analyze a smooth disk rotating in still fluid. To ensure the physical properties of the situation are captured, the temperature and velocity profiles of the fluid are verified to match the results reported in the literature. For a rotating disk, both temperature and velocity profiles must approach a minimum value of zero at heights far from the surface of the disk and a maximum value near the surface of the disk. By studying the velocity and temperature profiles, an estimate for the proper size of the computational domain within the CFD software is obtained. The size of the computational domain, when too small, can impact the results of the convective heat transfer coefficient due to the boundary disrupting the fluid. Within the CFD software, two methods can be utilized to obtain results for the convective heat transfer coefficient. The methods being, the global rotation method, and the local rotation (sliding) method. A comparison between the two methods and the expected heat transfer coefficient values predicted by correlations found in previous works of literature allows for the validation of the CFD software. Both methods agree with the expected heat transfer coefficient value and show agreement by maintaining a percent difference below three percent for low angular velocities. The global rotation method is best suited for a singular disk rotating in still air. When testing for faster angular speeds, the global rotation method was utilized and maintained low percent differences, below three percent, once an appropriate mesh was established and the turbulent parameters were set correctly. By having results that agree with correlations from previous literature, CFD software, once verified and validated, is a viable option when designing disk brakes, turbomachinery, and the wheels of a train.