A study on flow between parallel disks for cooling

摘要

The size of the motor depends on the required electrical and mechanical characteristics, temperature rise limit. As torque increases, heat generation increases. In order to solve this problem, it is necessary to cool the motor with high efficiency. Air cooling methods are often used for many methods of cooling. In this cooling method, cooling is performed using air. Therefore, complicated equipment is unnecessary. So, the structure of the motor can be simplified. There is also an advantage that the product can be produced at low cost. However, as the number of iron cores inside the motor increases, sometimes motor breaks out. Furthermore, when miniaturization and weight reduction are intended, the power loss density increases and the temperature rise limit of insulation becomes a problem. Because the experiment is expensive, it is important to observe the cooling state of the iron plate by highly accurate simulation. Under these circumstances, we have developed a solid-fluid heat coupling simulation method in this research. By applying this method, it is possible to find the optimum operating state of the motor. In the conventional calculation method, the temperature of the fluid / solid interface is calculated by using the thermal conductivity calculated by the harmonic mean of each. However, when this calculation method is used, many lattice points are required in order to obtain the temperature of the interface with high accuracy. Also, it is impossible to calculate the discontinuity of temperature at the interface. Therefore, in this study, we calculate the thermal conductivity in each phase by using the thermal conductivity of each fluid and solid, and calculate the temperature of the interface by simultaneous heat flux condition between fluid solids. By using this calculation method, there is an advantage that it is possible to accurately obtain the temperature of the interface even with a small number of grids. Also, even in the heat transfer phenomena of solids and fluids having any shape, it is possible to calculate the strict interface temperature based on the heat conduction ratio. Using this calculation method, we report numerical simulation results by inserting a plurality of plates inside a concentric double cylinder to form a gap.