螺旋槽干气密封端面气膜温度场的数值分析

为了解因黏性剪切和压缩膨胀等因素导致干气密封气体流经密封端面时的温度变化,以空气润滑螺旋槽干气密封为研究对象,利用CFD软件的三维数值模拟功能,分别研究了膜厚t、转速n和密封气体压力po对稳态运行时端面气膜温度分布的影响.结果表明:气膜温度沿径向和周向均发生变化,螺旋槽内靠近外径处的气体温度较低.随着膜厚t的增大,气膜的高温区由台区逐渐转移到密封坝区.膜厚t越大,端面气膜的平均温度越低.转速n对于气膜温度的影响明显,随着转速n增大,气膜温度迅速上升.而随着密封气体压力po的增大,泄漏量St逐渐增大,通过泄漏气体带走的热量相应增大,气膜温度相应降低.

Numerical analysis of temperature field of gas film in spiral groove dry gas seal

When the gas flows through the seal faces of a dry gas seal, the temperature of the gas film can vary on the faces because the leaked gas is subject to viscous shear, compression and expansion and so on. Taking an air-lubricated spiral groove dry gas seal as the study model, a three dimensional, steady thermal fluid flow simulation is performed with a commercial CFD software. The effects of film thickness, rotational speed, and sealing pressure on gas film temperature distribution are investigated. The results show that the gas film temperature varies in the radial and circumferential directions, and a lower gas film temperature appears near the inlet of the groove. The higher temperature zone shifts to the dam from the land gradually with the increasing film thickness. The thicker the gas film, the lower the average film temperature. The film temperature is significantly affected by rotational speed. As the rotational speed increases, the gas film temperature rises rapidly. However, an increased sealing pressure reduces the film temperature. The main reason for this is that the gradually increased gas leakage takes more heat with it as the pressure becomes high.