一种新型矿用高速抢险泵冷却循环回路的设计方法

Design of cooling circuit of new mine high speed rescue pump

为满足煤矿透水发生时快速救援的要求,提出1种新型体积小、流量大、扬程高的矿用高速抢险泵。其机组采用上机下泵的一体化结构,电机为大功率高速湿式电机。在同等流量、扬程的情况下,与同类产品相比,矿用高速抢险泵长度减少了31%,重量减少了51.2%。以矿用高速抢险泵1250 kW规格为例,对矿用高速抢险泵的冷却循环回路进行了设计研究。结合变频高速电机内部结构,提出正、逆2种循环形式的冷却循环回路。基于SST k-ω湍流模型和总热传输模型,通过求解三维N-S方程及能量方程,对2种循环回路的内部流场和温度场进行了数值模拟分析。模拟结果表明,正、逆循环回路总压降分别为109.95和107.83 m。2种循环回路形式下,最低压力区域均出现在推力盘底部,其中逆循环回路最低压力为-107.03 kPa,远大于正循环回路中最低压力-1584.2 kPa;最高温升区域出现在径向滑动轴承液膜表面,正、逆循环回路中最高温度值为56.26和57.17℃,差值为0.91℃。从避免汽蚀发生的方面考虑,样机最终采用了逆循环回路的设计方式,通过实验验证了矿用高速抢险泵样机的水力性能与电机温升特性。实验结果表明,其水力性能符合设计求;且性能实验中,电机腔内最高温度为51.25℃;寿命实验中,电机腔温度在50.34~51.15℃内波动;电机腔温升符合要求并满足1250 kW规格高速抢险泵变频高速电机的散热需要。该研究可为大功率高速抢险泵循环回路的设计提供借鉴。

To meet the requirements of rapid rescue when mine water flooding occurs,a new type of mine high speed rescue pump with small volume,large flow and high head was proposed in this paper.The whole structure was a combination of upper motor and lower pump.With the same flow rate and head,the length and weight of the prototype were reduced by 31% and 51.2% compared with the pump in the current market.Taking the 1250 kW series as an example,according to the current structure of the variable frequency high speed motor,two cooling circuits were proposed which included the positive and reverse circuits.Based on the k-ωturbulence model and the total heat transfer model,the internal flow field and temperature field of the two circulating loops were numerically simulated by solving the three-dimensional N-S equation and energy equation.The numerical simulation results showed that:it was found that the pressure drop were 109.95 m in the positive circuit and 107.83 m in the reverse circuit.In the respect of pressure distribution,the lowest pressure region appeared at the bottom of the thrust plate in the both circuits.However,in terms of the lowest pressure in the circuit,the value for positive circuit was-1584.2 kPa which was much smaller than that in the reverse circuit with the value of-107.03 kPa.In the respect of tem-perature field,the highest temperature always appeared at the film of the bearing.In the positive circuit,the temperature was 56.26℃,which was 0.91℃ less than 57.17℃ in the reverse circuit.Considering avoiding cavitation,the reverse circuit was adopted for cooling.Finally,the hydraulic performance and temperature rise characteristics in the motor chamber of the pump designed by reverse circulation loop were verified by experiments.The experimental results showed that the hydraulic performance of the pump accorded with the design conditions.In the performance,the highest temperature in the motor chamber was 51.25℃;in the life test,the temperature varied from 50.34℃ to 51.15℃.The temperature range could meet the cooling requirements for the variable frequency high speed motor of 1250 kW.