Dynamic Leakage Analysis of Noncontacting Finger Seals Based on Dynamic Model

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Kaibing Du ◽  
Yongjian Li ◽  
Shuangfu Suo ◽  
Yuming Wang
Keyword(s):  
Dynamic Analysis ◽  
Design Optimization ◽  
Gas Turbine ◽  
Dynamic Model ◽  
Natural Frequency ◽  
Friction Force ◽  
Dynamic Performance ◽  
Excitation Amplitude ◽  
Analysis Model ◽  
Turbine Engine

Noncontacting finger seals are new compliant seal in gas turbine engine sealing technology. Their potential hydrodynamic and hydrostatic lifting capabilities make them preferable to brush seals and contacting finger seals. The work concerns the mechanism of dynamic leakage of noncontacting finger seal, and a novel dynamic leakage analysis model is proposed. The model combines seal dynamic analysis and seal leakage analysis together to estimate seal dynamic performance through seal leakage. The nature of dynamic leakage performance affected by the change of seal–rotor clearance is revealed. Dynamic leakage increasing is mainly affected by ratio of friction force to finger stiffness, finger mass natural frequency, and rotor excitation amplitude. Results show that the leakage increasing caused by the rotor eccentricity is inevitable. In the design optimization of the noncontacting finger seal, the ratio of friction force to finger stiffness and the rotor excitation should be as small as possible, and the finger natural frequency should be as large as possible.

Steady and Dynamic Performance and Emissions of a Variable Geometry Combustor in a Gas Turbine Engine

2002 ◽  
Author(s):  
Y. G. Li ◽  
R. L. Hales
Keyword(s):  
Gas Turbine ◽  
Dynamic Performance ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Variable Geometry ◽  
Turbofan Engine ◽  
Turbine Engine ◽  
Control Schemes ◽  
Fuel Staging

One of the remedies to reduce the major emissions production of nitric oxide (NOx), carbon monoxide (CO) and unburned hydrocarbon (UHC) from conventional gas turbine engine combustors at both high and low operating conditions without losing its performance and stability is to use variable geometry combustors. This type of combustor configuration provides the possibility of dynamically controlling the airflow distribution of the combustor based on its operating conditions and therefore controlling the combustion in certain lean burn conditions. Two control schemes are described and analyzed in this paper: both are based on airflow control with variable geometry, the second including fuel staging. A model two-spool turbofan engine is chosen in this study to test the effectiveness of the variable geometry combustor and control schemes. The steady and dynamic performance of the turbofan engine is simulated and analyzed using an engine transient performance analysis code implemented with the variable geometry combustor. Empirical correlations for NOx, CO and UHC are used for the estimation of emissions. Some conclusions are obtained from this study: • With variable geometry combustors significant reduction of NOx emissions at high operating conditions and CO and UHC at low operating condition is possible; • Combustion efficiency and stability can be improved at low operating conditions, which is symbolized by the higher flame temperature in the variable geometry combustor; • The introduced correlation between non-dimensional fuel flow rate and air flow ratio to the primary zone is effective and simple in the control of flame temperature; • Circumferential fuel staging can reduce the range of air splitter movement in most of the operating conditions from idle to maximum power and have the great potential to reduce the inlet distortion to the combustor and improve the combustion efficiency; • During transient processes, the maximum moving rate of the hydraulic driven system may delay the air splitter movement but this effect on engine combustor performance is not significant.

Dynamic analysis and experimental verification of the carbon–carbon composite finger seal under complex working states

2018 ◽  
Vol 233 (8) ◽  
pp. 2914-2922
Author(s):  
Li-Na Wang ◽  
Yong Wang ◽  
Heng-Chao Sun ◽  
Guo-Hua Ren ◽  
Li-Chen Sun ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Dynamic Performance ◽  
Engineering Application ◽  
Carbon Composite ◽  
Theoretical Research ◽  
Aero Engine ◽  
Rotor Assembly ◽  
Dynamic Performance Analysis ◽  
Theoretical Results

The finger seal has an important influence on the performance of the aero-engine, and the effect of complex working states on the performance of the finger seal, which is located in the aero-engine, is also prominent. But so far, the finger seal performance under complex working states, which include the incline of the rotor, assembly condition, temperature effect, and impact effect, has not been investigated yet. Based on this, an equivalent dynamic model of finger seal is presented under complex working states, and the dynamic performance analysis of the finger seal is carried out by the model. The results show that the complex working states have larger influence on the finger seal performance. Meanwhile, an experimental research is carried out and the results are compared with the theoretical results. And then the validity of the equivalent dynamic model of the finger seal under complex working states is proved. The present work is conducive to improve the theoretical research system of finger seal, and promote the dynamic analysis technology to engineering application as well.

Steady and Dynamic Performance and Emissions of a Variable Geometry Combustor in a Gas Turbine Engine

2003 ◽  
Vol 125 (4) ◽  
pp. 961-971 ◽  
Author(s):  
Y. G. Li ◽  
R. L. Hales
Keyword(s):  
Gas Turbine ◽  
Dynamic Performance ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Variable Geometry ◽  
Turbofan Engine ◽  
Turbine Engine ◽  
Control Schemes ◽  
Fuel Staging

One of the remedies to reduce the major emissions production of nitric oxide NOx, carbon monoxide (CO), and unburned hydrocarbon (UHC) from conventional gas turbine engine combustors at both high and low operating conditions without losing performance and stability is to use variable geometry combustors. This type of combustor configuration provides the possibility of dynamically controlling the airflow distribution of the combustor based on its operating conditions and therefore controlling the combustion in certain lean burn conditions. Two control schemes are described and analyzed in this paper: Both are based on airflow control with variable geometry, the second including fuel staging. A model two-spool turbofan engine is chosen in this study to test the effectiveness of the variable geometry combustor and control schemes. The steady and dynamic performance of the turbofan engine is simulated and analyzed using an engine transient performance analysis code implemented with the variable geometry combustor. Empirical correlations for NOx, CO, and UHC are used for the estimation of emissions. Some conclusions are obtained from this study: (1) with variable geometry combustors significant reduction of NOx emissions at high operating conditions and CO and UHC at low operating condition is possible; (2) combustion efficiency and stability can be improved at low operating conditions, which is symbolized by the higher flame temperature in the variable geometry combustor; (3) the introduced correlation between nondimensional fuel flow rate and air flow ratio to the primary zone is effective and simple in the control of flame temperature; (4) circumferential fuel staging can reduce the range of air splitter movement in most of the operating conditions from idle to maximum power and have the great potential to reduce the inlet distortion to the combustor and improve the combustion efficiency; and (5) during transient processes, the maximum moving rate of the hydraulic driven system may delay the air splitter movement but this effect on engine combustor performance is not significant.

Dynamic Analysis and Optimization for Wafer Handling Robot

2014 ◽  
Vol 898 ◽  
pp. 657-662
Author(s):  
Ming Yue Wu ◽  
Yan Jie Liu ◽  
He Gao Cai
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Natural Frequency ◽  
Dynamic Optimization ◽  
Dynamic Characteristics ◽  
Low Frequency ◽  
Numerical Procedure ◽  
Optimization Result

Aiming at suppressing the vibration of low-frequency, a procedure of dynamic optimization of wafer handling robot is presented. The dynamic model of wafer handling robot is firstly build, and following that the dynamic characteristics of the robot are analyzed to find the main parameters which will influence the natural frequency. Then, the numerical procedure of the optimization of the natural frequency is introduced, and the constraint functions are obtained by considering the workspace and the structure of the robot. And at the end, as a case study, the procedure is applied to a wafer handling robot. Optimization result shows that the natural frequency is enhanced to 32.56Hz after the optimization.

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