开架发电机组冷却系统性能评估及结构改进

Performance Evaluation and Structure Improvement of Cooling System of Open Frame Generator Unit

发电机组冷却系统流场分析及冷却性能评估有助于确认冷却系统总流量大小、冷却风量分配比例和冷却风流速分布特性,确保风道流量分配均匀和高温区域冷却良好。以某开架发电机组为研究对象,根据冷却系统设计要点对其冷却系统进行了初始布局结构设计,采用流体分析软件STAR-CCM+搭建了开架发电机组冷却系统流场分析模型。结果表明,缸头风道风量占发动机风道总风量的48.77%,箱体底部风量占比为6.7%,不利于发动机缸头和机油的冷却。通过调整导流罩与散热片间距、风扇罩更改为渐扩线形式、箱体开孔与散热片形状及导流的匹配改动、拉盘开孔增大等方式形成了开架发电机组冷却系统结构改进方案。改进后该机组缸头风道风量占发动机风道总风量的61.83%,箱体底部风量占比为13.04%。缸头风道风量及箱体底部风量基本满足发动机缸温及油温的冷却需求。发动机各风道冷却风速度分布均匀,电机冷却较好,空滤器进风均来源于外界冷却风;消声器表面风速分布均匀,不存在流动死区且靠排气管处风速较大。该发电机组冷却系统可对机组实现较好的冷却,保障机组正常且长时间运行。研究结果可为发电机组冷却系统布局设计及结构改进提供参考。

The flow field analysis and cooling performance evaluation of the cooling system of the generator unit are helpful to confirm the total flowrate of cooling system,the distribution proportion of cooling air volume and the velocity distribution characteristics of cooling air,so as to ensure uniform flow distribution in the air duct and good cooling in the high-temperature area.Taken an open frame generator unit as the research object,the initial layout and structure design of the cooling system are designed according to the key design points of cooling system,and the flow field analysis model of the cooling system of the open frame generator unit is built by fluid flow analysis software STAR-CCM+.The results show that the air volume of cylinder head air duct accounts for 48.77%of the total air volume of engine air duct,and the air volume at the bottom of engine crankcase accounts for 6.7%,which is not conducive to the cooling of engine cylinder head and engine oil.The structural improvement design of the cooling system of the open frame generator unit is formed by adjusting the spacing between the deflector and the heat sink,changing the fan cover to the form of gradually expanding line,changing the matching between the hole opening and the shape of the heat sink and the diversion,and increasing the air inlet area through adding more openings on pull plate.After structure improvement,the air volume of the cylinder head air duct of the unit accounts for 61.83%of the total air volume of the engine air duct,and the air volume at the bottom of engine crankcase accounts for 13.04%.The air volume of cylinder head air duct and the air volume at the bottom of engine crankcase basically meet the cooling requirements of engine cylinder temperature and oil temperature.The cooling air velocity of each air duct of the engine is evenly distributed,and the motor is well cooled,and the air inlet of the air filter comes from the outside fresh cooling air.The air velocity on the muffler surface is evenly distributed.There is no flow dead zone,and the air velocity near the exhaust pipe area is large.The cooling system of the generator unit can realize better cooling of the unit and ensure the normal and long-term operation of generator unit.The research results can provide simulation data support and theoretical reference for the layout design and structure improvement of generator unit cooling system.