Heat transfer is the branch of physics that deals with the study of how heat energy is transferred from one point to another. This can include the study of conduction, convection, and radiation. CFD can be used to simulate and analyze heat transfer processes in a wide range of applications, including HVAC systems, heat exchangers, combustion systems, and electronic cooling. CFD simulations can be used to predict the behavior of temperature, velocity, and thermal gradients, as well as the heat transfer coefficients in a given system. This can be used to optimize the design of heat exchangers and other thermal systems, with the goal of increasing efficiency and reducing energy consumption. Additionally, CFD simulations can be used to study the behavior of multi-phase systems, such as boiling and condensation, which are commonly found in heat transfer applications, and to predict the performance of heat exchangers under different conditions. Overall, CFD is a powerful tool that can provide valuable insights into heat transfer processes, helping to improve the performance and efficiency of thermal systems.