过热蒸汽下分级机主轴系统热态特性的数值模拟

过热蒸汽气流磨是一种新型的粉体加工设备,由于其工质过热蒸汽温度较高,在系统运行时需对与其配套的分级机的轴承进行冷却,其冷却要求为保证轴承温度维持在75℃以下及避免过度冷却,使粉碎腔中轴段的温度高于100℃,保证粉碎腔中不出现冷凝现象。为寻求一种有效的冷却方法,以四川绵阳流能粉体设备有限公司某型号过热蒸汽分级机为原型建模,利用有限元分析软件ANSYS,对其在自然冷却、水冷轴承座和油循环冷却三种条件下主轴系统的温升进行了数值模拟分析。通过模拟结果得：在自然冷却的条件下,分级机上下轴承温升较快,发热非常严重,轴承外圈最高温度分别达到145℃和177℃,超过普通轴承的极限使用温度;在采用水冷轴承座时,运行约45分钟,分级机主轴系统温度达到平衡,上下轴承外圈温度最高不超过33℃和46℃,同时粉碎腔中轴段的最低温度高于100℃;在采用油循环冷却时,运行约80分钟,主轴系统温升达到平衡,上下轴承外圈温度不超过43℃和56℃,且粉碎腔中轴段表面温度最低温度高于100℃。由以上结果可看出水冷轴承座和油循环冷却两种方式均能满足冷却要求,但油循环冷却造价昂贵,且油液密封困难,而水冷轴承座这种方式简单易行,故建议采用水冷轴承座这种方式对主轴系统进行冷却。

The thermal-state study on classifier's spindle system on the condition of superheated steam

Superheated steam jet mill is a new kind of powder processing equipment,because of the high temperature of the superheated steam,cooling for the bearings of classifer which matched this machine is needed.Requirements for cooling are： to ensure the temperature of bearings below 75℃;to avoid Excessive cooling and make the temperature of shaft segment in the grinding cavity was above 100℃.To ensure condensation won＇t appear in the grinding cavity.In order to seek a effective way to cool down the temperature of the bearings of classifier.In this paper,a certain type of superheated steam classifier of Mianyang Liueng powder equipment.ltd in Sichuan was used as an foundation to build finite element model,the temperature distribution of spindle system of classifier was simulated on the condition of air cooling,water cooling and oil-circulation cooling Using finite element analysis software ANSYS,Through the simulation results： on the condition of natural cooling,the temperature increased quickly,and the maximum temperature of the outer ring of the upper and lower bearing reached respectively 145℃ and 177℃,which has exceeded the normal working limit of general bearing;on the condition of water cooling,the temperature of the spindle system reached equilibrium after 45 minutes.The maximum temperature of the outer ring of the upper and lower bearing reached respectively 33℃ and 46℃ and the minimum temperature of shaft segment in the grinding cavity was above 100 ℃;3.on the condition of oil-circulation cooling,the temperature of the spindle system reached equilibrium after about 80 minites.The maximum temperature of the outer ring of the upper and lower bearing reached respectively 43 ℃ and 56 ℃ and the minimum temperature of shaft segment in the grinding cavity was above 100 ℃.Thus we draw a conclusion that both water cooling and oil-circulation cooling can satisfy the requirement of superheated steam jet mill.but the cost of oil-circulation cooling is high compared with water cooling and it＇s difficult to realize oil sealing,so the latter is advised.