Abstract
In commercial aviation industry, reduction of aircraft emissions is an urgent priority. Engine manufacturers in particular have worked long and hard to improve each component of the engine. MEE (More Electric Engine) is a new engine system concept that seeks engine efficiency improvements and emissions reduction in fuel burn and CO2. The key concept of the MEE involves the architecture for the electrical power generation by the engine and changing the power source for accessories from mechanical/hydraulic to a fault-tolerant electric motor. Due to its contribution to fuel burn reduction, electrification of the engine fuel pump system is a primary issue. The MEE motor-driven fuel pump is usually called electric fuel pump. There are several technical challenges for the design of the pump, including high power-weight-ratio and reliability. However, when the electric fuel pump delivers and regulates fuel into the combustor, the motor-driven pump generates much heat especially at high delivery pressure or flow rate, which deteriorates the running condition, life, and safety of the pump and even the engine. Thus, it is an urgent need to take reasonable heat dissipation measures for the motor cooling. Modeling techniques and characteristic study for heat dissipation is indispensable to cooling scheme design and optimization. Heat dissipation of the motor mainly involves heat generation calculation and heat dissipation scheme. It is necessary to minimize the heat generated by the motor loss. On the other hand, it is also necessary to improve the heat dissipation capacity of the motor as much as possible from the perspective of cooling performance. In order to obtain accurate heat dissipation characteristics of a fuel-cooling shell of an electric fuel pump, a multi-physical coupled model is built. The heat dissipation characteristics of the shell are numerically simulated under typical conditions. The results show that the loss of the stator/rotor core increases proportionally with the rotation speed, while the permanent magnet loss increases exponentially with the rotation speed. The temperature distribution of each part of the permanent magnet motor and fuel cooling shell is obtained. The fuel flow rate through the shell directly impacts the heat dissipation intensity, but the dissipation efficiency decreases with the increase of the flow rate. Based on the multi-physical coupled model, the effects of different parameters on the cooling are obtained, which proves the necessity of the model proposed in the paper when characterizing the heat distribution inside the pump.
