Study on leakage characteristics and parameter influence of pump-out spiral groove oil-gas seal

doi:10.11949/0438-1157.20230234

Abstract

Abstract:

Taking the pump-out spiral groove oil-gas seal as the research object, the two-phase Reynolds model for solving the flow field of oil-gas seal was established based on the continuity equations of oil and gas phase, respectively. The flow field distribution of the oil-gas sealing medium is obtained by using the finite volume method to discretize and program the solution. The calculation accuracy and efficiency of commercial software VOF model, single-phase Reynolds model and two-phase Reynolds model in solving the flow field of oil-gas seal were compared and analyzed. The effects of operating parameters such as seal gap, oil-gas ratio, rotational speed, medium pressure, and seal ring size on the flow field and steady-state performance of the oil-gas seal were studied, and the near-zero leakage characteristics of the oil-gas seal and its key influencing factors were discussed. The results show that the proposed two-phase Reynolds model method is a high precision and efficient numerical method for calculating the flow field of oil-gas seal. It has the approximate accuracy with the commercial software VOF model, while the calculation time is reduced by one order of magnitude. The medium leakage characteristics and near zero leakage pressure differential of oil-gas seal are mainly affected by the seal clearance, rotational speed and seal ring width. It is expected to achieve zero leakage of oil-gas through the reasonable value of the above-mentioned parameters.

Key words: gas-liquid flow, numerical simulation, optimal design, oil-gas face seal, turbocharger

摘要：

以泵出型螺旋槽油气密封为研究对象，基于油相和气相连续性方程推导并建立了油气密封流场求解的双相雷诺模型，采用有限体积法离散和编程求解获得了油气密封介质流场分布，对比分析了商用软件VOF模型、单相雷诺模型和双相雷诺模型在求解油气密封流场中的计算精度和效率，研究了密封间隙、油气比、转速、介质压力等运行参数和密封环尺寸对油气密封流场和稳态性能的影响，重点探讨了油气密封近零泄漏特性及其关键影响因素。结果表明，提出的双相雷诺模型求解方法是一种高精度、高效率的油气密封流场数值模拟方法，具有与商用软件VOF模型近似的精度，但计算时间降低1个数量级；油气密封的介质泄漏特性和近零泄漏压差主要受到密封间隙、转速和端面宽度的影响，通过上述参数的合理取值有望实现油气介质的零泄漏。

关键词: 气液两相流, 数值模拟, 优化设计, 油气端面密封, 涡轮增压器

CLC Number:

TH 117.2

Jinbo JIANG, Xin PENG, Wenxuan XU, Rixiu MEN, Chang LIU, Xudong PENG. Study on leakage characteristics and parameter influence of pump-out spiral groove oil-gas seal[J]. CIESC Journal, 2023, 74(6): 2538-2554.

江锦波, 彭新, 许文烜, 门日秀, 刘畅, 彭旭东. 泵出型螺旋槽油气密封泄漏特性及参数影响研究[J]. 化工学报, 2023, 74(6): 2538-2554.

Figures/Tables 23

Fig.1 Structural diagram of pump-out spiral groove oil-gas seal

Fig.2 Schematic diagram of finite volume meshing

Fig.3 Numerical solution flow of oil-gas seal based on two-phase Reynolds model

Fig.4 Mesh generation and boundary condition setting in computational domain

Table 1 Initial parameters adopted in calculating performance of gas-oil seal

参数	数值	参数	数值
端面内径 r_i/mm	29.5	外径侧压力 p_o/kPa	150
端面外径 r_o/mm	37.5	内径侧压力 p_i/kPa	100
螺旋槽深度 h_g/μm	5	外侧油气比 F_l	0.1
螺旋角 β/(°)	20	介质温度 T/K	300
周向槽宽比 δ	0.5	转速 n/(r·min^-1)	3000
槽数 N_g	12	气体黏度 μ_g/(μPa·s)	17.9
槽根半径 r_g/mm	34	润滑油黏度 μ_l /(mPa·s)	42.5
气膜厚度 h₀/μm	3	润滑油密度 ρ_l /(kg·m^-3)	886

Fig.5 Variation of opening force and leakage rate of oil-gas seal with grid number

Fig.6 Schematic diagram of axial characteristic section of oil-gas seal fluid domain

Fig.7 Oil-gas ratio and velocity distribution in different axial sections based on VOF model

Table 2 Calculation results of oil-gas seal flow field obtained by three different numerical models

模型	油气比分布	压力分布	间隙中面速度分布
双相雷诺模型
单相雷诺模型
VOF模型

Fig.8 Steady state performance parameters and pressure distribution of oil-gas seal obtained by three numerical models

Fig.9 Steady state performance parameters of oil-gas seal under different seal clearance

Table 3 Calculation results of oil-gas seal flow field distribution under different seal clearance

h/μm	压力分布	油气比分布	间隙中面速度分布
2
3
4

Fig.10 Steady state performance of oil-gas seal under different oil-gas ratio

Fig.11 Distribution of oil-gas seal pressure under different oil-gas ratio

Fig.12 Average velocity and medium density distribution at seal outlet under different oil-gas ratio

Fig.13 Steady state performance parameters of oil gas seal under different rotational speed

Fig.14 Oil-gas ratio and mid-surface velocity distribution of oil-gas seal under different rotational speed

Fig.15 Steady state performance of oil-gas seal under different internal and external radial pressure

Fig.16 Oil-gas ratio and mid-surface velocity distribution of oil-gas seal under different medium pressure

Fig.17 Influence of seal face width and inner diameter on oil and gas leakage rate

Fig.18 Effect of seal face width on seal oil-gas ratio and pressure distribution

Fig.19 Near zero leakage limit differential pressure of oil-gas seal under different operating parameters

Table 4 Operating condition parameters corresponding to different operating conditions

Case	p_o/kPa	n/(r·min^-1)	F_l
1	120	3000	0.1
2	150	2000	0.1
3	150	3000	0.1
4	120	3000	0.2

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