Elastic clearance change in axisymmetric shearing process

2016 ◽  
Author(s):  
Yoshinori Yoshida
Keyword(s):  
Clearance Change

scholarly journals The Influence of the Axial Rub Added in the Radial Rub on the Wear of the Seal Fins during the High Speed Rub of Labyrinth-Honeycomb Seal

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1997
Author(s):  
Bin Lu ◽  
Haijun Xuan ◽  
Xiaojian Ma ◽  
Fangjun Han ◽  
Weirong Hong ◽  
...  
Keyword(s):  
Wear Rate ◽  
High Speed ◽  
State Of The Art ◽  
Negative Influence ◽  
Axial Thrust ◽  
Cross Sectional ◽  
Honeycomb Seal ◽  
Aero Engine ◽  
Honeycomb Seals ◽  
Clearance Change

Labyrinth-honeycomb seals are a state-of-the-art sealing technology commonly used in aero-engine interstage seal. The undesirable severe rub between the seal fins and the honeycomb due to the clearance change may induce the cracking of the seal fins. A pervious study investigated the wear of the seal fins at different radial incursion rates. However, due to the axial thrust and mounting clearance, the axial rub between the seal fins and the honeycomb may occur. Hence, this paper focuses on the influence of the axial rub added in the radial rub on the wear of the seal fins. The rub tests results, including rubbing forces and temperature, wear rate, worn morphology, cross-sectional morphology and energy dispersive spectroscopy results, are presented and discussed. Overall, the participation of the axial rub leads to higher rubbing forces, temperature, and wear rate. The tribo-layer on the seal fin is thicker and the cracks are more obvious at high axial incursion rate. These phenomena indicate the axial rub has a negative influence on the wear of the seal fins and should be avoided.

scholarly journals Investigation of Mechanical Clearance Change with Thermal Flying-height Control Slider at High Altitude

2010 ◽  
Vol 4 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Satoru OOKUBO ◽  
Toshiya SHIRAMATSU ◽  
Masayuki KURITA ◽  
Hidekazu KOHIRA ◽  
Yoshinori TAKEUCHI
Keyword(s):  
High Altitude ◽  
Flying Height ◽  
Height Control ◽  
Thermal Flying Height Control ◽  
Clearance Change

scholarly journals FEATURES OF CREATININ CLEARANCE CHANGE IN ISCHEMIC HEART DISEASE COMPLIED BY OBESITY

2019 ◽  
Vol 3 (152) ◽  
pp. 143
Author(s):  
L. Ye. Lapovets L. ◽  
H. V. Bashta ◽  
M. M. Shchurko ◽  
S. O. Tkachuk
Keyword(s):  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Ischemic Heart ◽  
Clearance Change

Numerical Calculation of Seal Clearance Change in Installation Process of a 1000MW Nuclear Steam Turbine HIP Casing

2020 ◽  
Author(s):  
Daohui Ji ◽  
Ziyue Mei ◽  
Wei Jiang ◽  
CaiYan Xiang ◽  
Danmei Xie ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Nuclear Power ◽  
Complex Structure ◽  
Steam Turbines ◽  
Maximum Deformation ◽  
Intermediate Pressure ◽  
Geometry Model ◽  
Whole Process ◽  
Calculation Results ◽  
Clearance Change

Abstract During installation process, most of 1000MW-class nuclear power steam turbines will undergo certain deformations due to their own big size and heavy weight, which will change seal clearances in the steam passage. The clearance change will affect steam turbine’s efficiency, and may cause rubbing faults and even strong abnormal vibration, affecting the safety of the steam turbine. Moreover, limited by the complex structure and measurement method, it is difficult to measure deformation and seal clearance accurately, so it is necessary to study the change tendency of the clearance in the installation process. In this paper, a HIP (High and Intermediate Pressure) casing of a 1000MW nuclear steam turbine was taken as the research object, and its 3D geometry model is established based on Pro/E software. By using ANSYS WORKBENCH, we calculated the deformation of the HIP casing during installation with five steps, which are named as: ① lower casing with lower diaphragms, ② step ① + upper diaphragms, ③ step ② + upper casing, ④ step ③ + bolting, and ⑤ replacing the support. Then we analyzed the change of the seal clearance during the installation process by deformation differences of some points under different conditions. The calculation results show that the maximum deformation of the HIP Casing during the installation process occurs in the middle of casing close to the IP (Intermediate Pressure) casing. The relative change of the clearance during the whole process is 0.6–0.8 mm. The change of seal clearance is largest at the first-stage of IP casing, and it can be 0.8mm during replacement of the support.

scholarly journals An Improved Blade Vibration Parameter Identification Method considering Tip Clearance Variation

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Liang Zhang ◽  
Qidi Wang ◽  
Xin Li
Keyword(s):  
Parameter Identification ◽  
Eddy Current ◽  
Vibration Amplitude ◽  
Tip Clearance ◽  
Vibration Parameter ◽  
Blade Vibration ◽  
Average Value ◽  
Blade Tip ◽  
Vibration Parameters ◽  
Clearance Change

Blade tip timing (BTT) technology is the most effective means for real-time monitoring of blade vibration. Accurately extracting the time of blade tip reaching the sensors is the key to ensure the accuracy of the BTT system. The tip clearance changes due to various complex forces during high-speed rotation. The traditional BTT signal extraction method does not consider the influence of tip clearance change on timing accuracy and introduces large timing errors. To solve this problem, a quadratic curve fitting timing method was proposed. In addition, based on the measurement principle of the eddy current sensors, the relationship among the output voltage of the eddy current sensor, tip clearance, and the blade cutting magnetic line angle was calibrated. A multisensor vibration parameter identification algorithm based on arbitrary angular distribution was introduced. Finally, the experiments were conducted to prove the effectiveness of the proposed method. The results show that in the range of 0.4 to 1.05 mm tip clearance change, the maximum absolute error of the timing values calculated by the proposed method is 26.0359 us, which is much lower than the calculated error of 203.7459 us when using the traditional timing method. When the tip clearance changed, the constant speed synchronous vibration parameters of No. 0 blade were identified. The average value of the vibration amplitude is 1.0881 mm. Compared with the identification results without changing tip clearance, the average value error of the vibration amplitude is 0.0017 mm. It is proved that within the blade tip clearance variation of 0.4 to 0.9 mm, the timing values obtained by the proposed timing method can accurately identify the vibration parameters of the blade.

Numerical Calculation of Seal Clearance Change in Installation Process of a 1000MW Nuclear Steam Turbine HIP Casing

2021 ◽  
Author(s):  
Daohui Ji ◽  
Ziyue Mei ◽  
Wei Jiang ◽  
Caiyan Xiang ◽  
Danmei Xie ◽  
...  
Keyword(s):  
Numerical Calculation ◽  
Steam Turbine ◽  
Clearance Change

Endwall Flow Development Across a Contra-Rotating Fan Unit

2000 ◽  
Author(s):  
S. Kumar ◽  
Bhaskar Roy
Keyword(s):  
Experimental Data ◽  
Tip Clearance ◽  
Fluid Mechanic ◽  
Axial Fan ◽  
Flow Measurements ◽  
Blade Loading ◽  
Flow Development ◽  
Zone Of Influence ◽  
Clearance Change ◽  
Twin Rotor

An experimental study has been made to understand the development of endwall flow across a low speed twin-rotor contra-rotating fan unit. Fluid mechanic studies of flow field in the tip region of an axial fan and of a contra-rotating unit were carried out. The fluid mechanic parameters, including flow angles, velocities and static and stagnation pressures, were obtained downstream of the rotors and at one axial location upstream of the first fan (inlet). The flow measurements were done up to 50% of the span from the blade tips. The steady state experimental data of an isolated axial fan indicates that the span wise penetration of this zone is dependent on the tip clearance and the blade loading. Similar effects would normally be expected on the contra-rotating rotors. The experimental data of the contra-rotating unit, however, indicate that neither the blade loading nor the tip clearance change (of the rear fan) affect the performance of the contra-rotating stages as significantly. The span wise zone of influence near the endwall and corresponding flow development due to tip clearance and blade loading seems to be reduced by the rear contra-rotating fan.

scholarly journals Experimental Investigation of Factors Influencing Operating Rotor Tip Clearance in Multistage Compressors

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Reid A. Berdanier ◽  
Nicole L. Key
Keyword(s):  
Axial Compressor ◽  
Tip Clearance ◽  
Additional Consideration ◽  
Temperature Variations ◽  
Operating Condition ◽  
Compressor Rotor ◽  
Third Stage ◽  
Multistage Compressors ◽  
Capacitance Probe ◽  
Clearance Change

An analysis of compressor rotor tip clearance measurements using capacitance probe instrumentation is discussed for a three-stage axial compressor. Thermal variations and centrifugal effects related to rotational speed changes affect clearance heights relative to the assembled configuration. These two primary contributions to measured changes are discussed both independently and in combination. Emphasis is given to tip clearance changes due to changing loading condition and at several compressor operating speeds. Measurements show a tip clearance change approaching 0.1 mm (0.2% rotor span) when comparing a near-choke operating condition to a near-stall operating condition for the third stage. Additional consideration is given to environmental contributions such as ambient temperature, for which changes in tip clearance height on the order of 0.05 mm (0.1% rotor span) were noted for temperature variations of 15°C. Experimental compressor operating clearances are presented for several temperatures, operating speeds, and loading conditions, and comparisons are drawn between these measured variations and predicted changes under the same conditions.

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