Numerical Simulation on Flow Field Characteristics and Cooling Performance Improvement of a Generator Unit

The high performance and lightweight design requirements of generator sets put higher requirements for their cooling system. When the generator unit works, the engine room temperature rises rapidly, and its poor heat dissipation performance directly affects its efficient and normal operation. In this work, a generator unit is taken as the research object, and CFD software STAR-CCM + 11.06 is used to simulate and analyze its flow field characteristics, and the single variable control method is used for finding a way for increasing the total inlet air quantity. Results show that the fan inlet air quantity of the original generator unit is only 40 g/s. The hot air re-circulation of the engine leads to the increase of the air inlet quantity of the motor, which is not conducive to motor cooling. The air quantity can be increased by adjusting the air inlet structure, reducing the air outlet resistance and adding thermal insulation baffle. After adding thermal insulation baffle, the air quantity of generator unit can be increased significantly and the phenomenon of hot air re-circulation can be effectively eliminated. According to the results of single factor analysis, the combination scheme of adjusting the layout of left and right air inlets, increasing the size of muffler cover outlet area and adding baffle to the engine is put forward. After optimization, the total fan inlet air quantity of generator unit is increased to 75.79 g/s. The total air quantity is increased significantly. The hot air re-circulation is fully eliminated by the heat insulation baffle, and the hot air circulation of motor is reduced, which is beneficial to motor cooling. The cell relative velocity magnitude of oil tank, carburetor and igniter is significantly improved. The total air inlet quantity of generator unit increases significantly and the airflow velocity in generator unit rises, which is beneficial to the cooling of generator unit and can ensure its efficient and normal operation. The results of flow field characteristics and cooling performance improvement study of generator unit can provide theoretical guidance for the design and improvement of generator units.