高速超临界二氧化碳干气密封实际效应影响分析
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摘要
超临界二氧化碳介质物性的特殊性使得高速超临界二氧化碳干气密封中的多种实际效应突显,忽略这些实际效应可能会给干气密封稳态性能求解带来较大误差。以螺旋槽干气密封为研究对象,推导了考虑惯性项和实际流态的膜压控制方程,采用有限差分法求得膜压分布,对比分析了基于实际修正模型与经典简化模型的高速超临界二氧化碳干气密封气膜刚度和泄漏率,分析了不同介质压力和速度条件下实际气体效应、惯性效应和湍流效应对气膜刚度和泄漏率的影响规律,揭示了三种效应对稳态性能的单独影响及交互影响机理。结果表明:在本文给定条件下,经典简化模型在速度较小时求得的泄漏率偏小,而在超高速时求得的气膜刚度和泄漏率都偏小;在超高速条件下,实际气体效应使气膜刚度和泄漏率都显著增大,湍流效应使气膜刚度增大,而使泄漏率减小,惯性效应对气膜刚度和泄漏率影响很弱;实际气体效应与湍流效应对稳态性能影响之间具有很强的交互影响关系。
The special properties of the supercritical carbon dioxide medium make the various practical effects in the high-speed supercritical carbon dioxide dry gas seal prominent, and ignoring these actual effects may bring large errors to the dry gas seal steady state performance solution. Taking spiral groove dry gas seal as the research object, the governing equation of film pressure considering inertia term and real flow state was derived. The film pressure distribution was obtained using finite difference method. The film stiffness and leakage rate of high-speed supercritical CO_2 dry gas seal based on the real modified model and classical simplified model were compared and analyzed. The effects of real gas effect, inertia effect and turbulent effect on film stiffness and leakage rate under different pressure and velocity conditions were analyzed. The independent and interactive effects of three effects on steady-state performance were revealed. Under the given conditions, the results show that the leakage rate calculated by the classical simplified model is smaller at low speed, and both film stiffness and leakage rate calculated by the classical simplified model are smaller at high speed. Under super-high speed condition, real gas effect significantly increases film stiffness and leakage rate of the gas film, while turbulent effect increases the stiffness of the gas film and reduces the leakage rate. Inertia effect slightly influences film stiffness and leakage rate.There is a strong interaction between real gas effect and turbulent effect on steady performance.
The special properties of the supercritical carbon dioxide medium make the various practical effects in the high-speed supercritical carbon dioxide dry gas seal prominent, and ignoring these actual effects may bring large errors to the dry gas seal steady state performance solution. Taking spiral groove dry gas seal as the research object, the governing equation of film pressure considering inertia term and real flow state was derived. The film pressure distribution was obtained using finite difference method. The film stiffness and leakage rate of high-speed supercritical CO_2 dry gas seal based on the real modified model and classical simplified model were compared and analyzed. The effects of real gas effect, inertia effect and turbulent effect on film stiffness and leakage rate under different pressure and velocity conditions were analyzed. The independent and interactive effects of three effects on steady-state performance were revealed. Under the given conditions, the results show that the leakage rate calculated by the classical simplified model is smaller at low speed, and both film stiffness and leakage rate calculated by the classical simplified model are smaller at high speed. Under super-high speed condition, real gas effect significantly increases film stiffness and leakage rate of the gas film, while turbulent effect increases the stiffness of the gas film and reduces the leakage rate. Inertia effect slightly influences film stiffness and leakage rate.There is a strong interaction between real gas effect and turbulent effect on steady performance.
引文
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[16]Ng C W,Pan C H T.A linearized turbulent lubrication theory[J].ASME Journal of Fluids Engineering,1965,87(3):675-682.
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[24]Conboy T M.Real-gas effects in foil thrust bearings operating in the turbulent regime[J].ASME Journal of Tribology,2013,135:031703-1-12.
[25]Taylor C M,Dowson D.Turbulent lubrication theoryapplication to design[J].ASME Journal of Lubrication Technology,1974,96(1):36-46.
[26]江锦波,陈源,赵文静,等.干气密封螺旋槽几何参数优选交互影响[J].化工学报,2018,69(4):1518-1527.Jiang J B,Chen Y,Zhao W J,et al.Interaction effect of optimized value of geometric parameters of spiral groove of dry gas seal[J].CIESC Journal,2018,69(4):1518-1527.
[27]彭旭东,江锦波,白少先,等.中低压干气密封螺旋槽结构参数优化[J].化工学报,2014,65(11):4536-4542.Peng X D,Jiang J B,Bai S X,et al.Structural parameter optimization of spiral groove dry gas seal under low or medium pressure[J].CIESC Journal,2014,65(11):4536-4542.
[28]徐奇超,江锦波,彭旭东,等.基于遗传算法的干气密封双向槽统一模型与参数优化[J].化工学报,2019,70(3):995-1005.Xu Q C,Jiang J B,Peng X D,et al.Unified model and geometrical optimization of bi-directional groove of dry gas seal based on genetic algorithm[J].CIESC Journal,2019,70(3):995-1005.
[29]Glienicke J,Launert A,Schlums H,et al.Non-contacting gas lubricated face seals for high PV values[J].Seals Flow Code Development,1994,1:367-378.
[30]Ochiai M,Hashimoto H.Static and dynamic characteristics of high-speed,stepped thrust gas-film bearings(Theoretical analysis considering fluid inertia forces)[J].Procedia Environmental Sciences,1997,63(613):3249-3256.
[31]Marquardt J T.Successful operational experience sealing supercritical CO2[C]//Supercritical CO2Power Cycle Symposium.Boulder,Colorado,USA:2015:1-5.
[32]李沛剑,郝小龙,宋满存,等.超临界二氧化碳涡轮发电机的设计及应用探讨[J].船舶科学技术,2017,39(9):111-116.Li P J,Hao X L,Song M C,et al.The design and application of a supercritical carbon dioxide turbo-generator[J].Ship Science and Technology,2017,39(9):111-116.
[33]Ahn Y,Bae S J,Kim M,et al.Review of supercritical CO2power cycle technology and current status of research and developmnt[J].Nuclear Engineering Technology,2015,47:647-661.
[2]Ahn Y,Bae S J,Kim M,et al.Review of supercritical CO2 power cycle technology and current status of research and development[J].Nuclear Engineering&Technology,2015,47(6):647-661.
[3]Thatte A,Dheeradhada V.Coupled physical performance predictions and risk assessment for dry gas seal operating in MW-scale supercritical CO2turbine[C]//Proceedings of ASME Turbo Expo 2016,Turbomachinery Technology Conference and Exposition,Seoul,South Korea 2016.
[4]Fairuz Z M,Jahn I H J.Performance of supercritical CO2 dry gas seal near the critical point[C]//Proceedings of ASME Turbo Expo2016,Turbomachinery Technology Conference and Exposition,Seoul,South Korea,2016.
[5]Baltadjiev N D.An investigation of real gas effects in supercritical CO2compressors[D].Massachusetts:Massachusetts Institute of Technology,2012.
[6]Jassim E,Abdi M A,Muzychka Y.Computational fluid dynamics study for flow of natural gas through high-pressure supersonic nozzles(part 1):Real gas effects and shockwave[J].Petroleum Science&Technology,2008,26(15):1757-1772.
[7]Muto D,Tsuboi N,Terashima H.Numerical study of real gas effects on shock tube problems at supercritical conditions[J].Transactions of the Japan Society for Aeronautical&Space Sciences Aerospace Technology Japan,2014,12(2):39-44.
[8]Fairuz Z M,Jahn I.The influence of real gas effects on the performance of supercritical CO2dry gas seals[J].Tribology International,2016,102:333-347.
[9]许恒杰,宋鹏云,毛文元,等.层流状态下高压高转速二氧化碳干气密封的惯性效应分析[J].化工学报,2018,69(10):4311-4323.Xu H J,Song P Y,Mao W Y,et al.Analysis on inertia effect of carbon dioxide dry gas seal at high speed and pressure under laminar condition[J].CIESC Journal,2018,69(10):4311-4323.
[10]Du Q W,Gao K K,Zhang D,et al.Effects of grooved ring rotation and working fluid on the performance of dry gas seal[J].International Journal of Heat and Mass Transfer,2018,126:1323-1332.
[11]温建全.超临界二氧化碳介质箔片轴承弹流耦合研究[D].哈尔滨:哈尔滨工业大学,2017.Wen J Q.The oretical study on characteristics of compliant foil bearings lubricated with supercritical carbon dioxide[D].Haerbin:Harbin Institute of Technology,2017.
[12]Conboy T M.Real-gas effects in foil thrust bearings operating in the turbulent regime[J].ASME Journal of Tribology,2013,135:031703-1-031703-12.
[13]Constantinescu V N.Basic relationships in turbulent lubrication and their extension to include thermal effects[J].ASME Journal of Lubrication Technology,1973,95(2):147-154.
[14]Constantinescu V N,Galetuse S.On the possibilities of improving the accuracy of the evaluation of inertia forces in laminar and turbulent films[J].ASME Journal of Tribology,1974,96(1):69-77.
[15]Constantinescu V N.On the influence of inertia forces in turbulent and laminar self-acting films[J].ASME Journal of Tribology,1970,92(3):473-480.
[16]Ng C W,Pan C H T.A linearized turbulent lubrication theory[J].ASME Journal of Fluids Engineering,1965,87(3):675-682.
[17]Ng C W.Fluid dynamic foundation of turbulent lubrication theory[J].Tribology Transactions,1964,7(4):311-321.
[18]Elrod H G,Ng C W.A theory for turbulent fluid films and its application to bearings[J].ASME Journal of Lubrication Technology,1967,89(3):346-362.
[19]Hirs G G.A bulk-flow theory for turbulence in lubricant films[J].ASME Journal of Lubrication Technology,1973,95(2):137-145.
[20]Wang J K,Khonsari M M.Application of Hopf bifurcation theory to rotor-bearing systems with consideration of turbulent effects[J].Tribology International,2006,39(7):701-714.
[21]Luan Z,Khonsari M M.Analysis of conjugate heat transfer and turbulent flow in mechanical seals[J].Tribology International,2009,42(5):762-769.
[22]Hashimoto H.The effects of fluid inertia forces on the static characteristics of sector-shaped,high-speed thrust bearings in turbulent flow regime[J].Journal of Tribology,1989,111:406-412.
[23]Hashimoto H.Performance characteristic analysis of sectorshaped pad thrust bearings in turbulent inertial flow regime under three types of lubrication conditions[J].ASME Journal of Tribology,1990,112:477-485.
[24]Conboy T M.Real-gas effects in foil thrust bearings operating in the turbulent regime[J].ASME Journal of Tribology,2013,135:031703-1-12.
[25]Taylor C M,Dowson D.Turbulent lubrication theoryapplication to design[J].ASME Journal of Lubrication Technology,1974,96(1):36-46.
[26]江锦波,陈源,赵文静,等.干气密封螺旋槽几何参数优选交互影响[J].化工学报,2018,69(4):1518-1527.Jiang J B,Chen Y,Zhao W J,et al.Interaction effect of optimized value of geometric parameters of spiral groove of dry gas seal[J].CIESC Journal,2018,69(4):1518-1527.
[27]彭旭东,江锦波,白少先,等.中低压干气密封螺旋槽结构参数优化[J].化工学报,2014,65(11):4536-4542.Peng X D,Jiang J B,Bai S X,et al.Structural parameter optimization of spiral groove dry gas seal under low or medium pressure[J].CIESC Journal,2014,65(11):4536-4542.
[28]徐奇超,江锦波,彭旭东,等.基于遗传算法的干气密封双向槽统一模型与参数优化[J].化工学报,2019,70(3):995-1005.Xu Q C,Jiang J B,Peng X D,et al.Unified model and geometrical optimization of bi-directional groove of dry gas seal based on genetic algorithm[J].CIESC Journal,2019,70(3):995-1005.
[29]Glienicke J,Launert A,Schlums H,et al.Non-contacting gas lubricated face seals for high PV values[J].Seals Flow Code Development,1994,1:367-378.
[30]Ochiai M,Hashimoto H.Static and dynamic characteristics of high-speed,stepped thrust gas-film bearings(Theoretical analysis considering fluid inertia forces)[J].Procedia Environmental Sciences,1997,63(613):3249-3256.
[31]Marquardt J T.Successful operational experience sealing supercritical CO2[C]//Supercritical CO2Power Cycle Symposium.Boulder,Colorado,USA:2015:1-5.
[32]李沛剑,郝小龙,宋满存,等.超临界二氧化碳涡轮发电机的设计及应用探讨[J].船舶科学技术,2017,39(9):111-116.Li P J,Hao X L,Song M C,et al.The design and application of a supercritical carbon dioxide turbo-generator[J].Ship Science and Technology,2017,39(9):111-116.
[33]Ahn Y,Bae S J,Kim M,et al.Review of supercritical CO2power cycle technology and current status of research and developmnt[J].Nuclear Engineering Technology,2015,47:647-661.