基于STAR-CCM+的发电机组流场分析及结构改进

发电机组高性能和轻量化的设计需求对其冷却系统提出了更高的要求。发电机组散热效果好可保证机组在最佳温度下工作，确保机组稳定可靠运行。为评估一款发电机组散热性能，基于CFD分析方法，采用流体分析软件STAR-CCM+对该发电机组进行流场分析，并依据流场分析结果针对性地提出结构改进方案。结果表明，发电机组原结构缸头出风直接吹向油箱底部，消声器表面无风流经，整机散热存在风险。通过添加缸头导风罩和消声器通风罩的方法改善了发电机整机散热性能:油箱底部表面速度降低明显，消声器处冷却风量从28.91 g/s提升至135.78 g/s，风量提升明显，消声器表面平均风速约4.04 m/s。温度实测结果表明，机组额定功率运转120 min，改进后机组的油箱底部和电机顶部温度降低了38 ℃和17 ℃。研究结果可为发电机组散热性能评估及结构改进提供参考。

Flow Field Analysis and Structure Improvement of Generator Unit Based on STAR-CCM+

The design requirements of high performance and lightweight of generator unit put forward higher requirements for its cooling system. The generator unit has good cooling performance, which can ensure the generator unit to work at the best temperature and ensure the stable and reliable operation of generator unit. In order to evaluate the cooling performance of a generator unit, based on the CFD analysis method, the fluid analysis software STAR-CCM+ was used to conduct the flow field analysis of generator unit, and the structural improvement design was put forward according to the flow field analysis results. The results showed that the air from the cylinder head of the original structure of the generator unit was directly blown to the bottom of oil tank, there was no air flow on the surface of the muffler, which was a cooling risk for generator unit. The cooling performance of generator was improved by adding cylinder head air guide cover and muffler ventilation cover. The surface velocity at the bottom of oil tank was significantly reduced, and the cooling air quantity at the muffler was increased from 28.91 g/s to 135.78 g/s. The average air velocity on the muffler surface was about 4.04 m/s. The experimental temperature results show that when the generator unit operates at rated power for 120 min, the temperature at the bottom of oil tank and the top of motor at the state of improved generator unit was reduced by 38 ℃ and 17 ℃. The research results can provide theoretical guidance for the evaluation of cooling performance and structural improvement of generator units.