Study on the Thermal Stress Couple Field of Nuclear Power Pump Mechanical Seal Based on ADINA

2014 ◽  
Vol 971-973 ◽  
pp. 1160-1164
Author(s):  
Hai Yang Zhang ◽  
Wei Bing Zhu ◽  
Gang Zhou ◽  
Xu Hao
Keyword(s):  
Thermal Stress ◽  
Contact Surface ◽  
Nuclear Power ◽  
Coupling Model ◽  
Maximum Temperature ◽  
Mechanical Seal ◽  
Temperature Decrease ◽  
Contact State ◽  
Stress Couple ◽  
Couple Field

In this paper, a two-dimensional axisymmetric thermal stress coupling model of mechanical seal’s rotator and stator components was established by ADINA, simplification and appropriate boundary constrained condition of stator and rotator was obtained by analyzing the contact state among the seal rings. It’s shown that the contact surface is equivalent to a resource of constant thermal, temperature of contact surface rises step by step and the location of the maximum temperature getting close to the midpoint within the contact surface according to the sliding time, the temperature gradient decrease along the worksheet so that the temperature decrease accordingly in a parabolic isogram.

scholarly journals Numerical and Experimental Study of Lightning Stroke to BIPV Modules

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 748
Author(s):  
Xiaoyan Bian ◽  
Yao Zhang ◽  
Qibin Zhou ◽  
Ting Cao ◽  
Bengang Wei
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Coupling Model ◽  
Maximum Temperature ◽  
Lightning Stroke ◽  
Study Results ◽  
Pv Modules ◽  
New Type ◽  
Metal Frame ◽  
Current Flows

Building Integrated Photovoltaic (BIPV) modules are a new type of photovoltaic (PV) modules that are widely used in distributed PV stations on the roof of buildings for power generation. Due to the high installation location, BIPV modules suffer from lightning hazard greatly. In order to evaluate the risk of lightning stroke and consequent damage to BIPV modules, the studies on the lightning attachment characteristics and the lightning energy withstand capability are conducted, respectively, based on numerical and experimental methods in this paper. In the study of lightning attachment characteristics, the numerical simulation results show that it is easier for the charges to concentrate on the upper edge of the BIPV metal frame. Therefore, the electric field strength at the upper edge is enhanced to emit upward leaders and attract the lightning downward leaders. The conclusion is verified through the long-gap discharge experiment in a high voltage lab. From the experimental study of multi-discharge in the lab, it is found that the lightning interception efficiency of the BIPV module is improved by 114% compared with the traditional PV modules. In the study of lightning energy withstand capability, a thermoelectric coupling model is established. With this model, the potential, current and temperature can be calculated in the multi-physical field numerical simulation. The results show that the maximum temperature of the metal frame increases by 16.07 °C when 100 kA lightning current flows through it and does not bring any damage to the PV modules. The numerical results have a good consistency with the experimental study results obtained from the 100 kA impulse current experiment in the lab.

Analysis of Transient Thermal Stress of IGBT Module Based on Electrical-Thermal-Mechanical Coupling Model

2014 ◽  
Vol 986-987 ◽  
pp. 823-827
Author(s):  
Qing Yuan Zheng ◽  
Min You Chen ◽  
Bing Gao ◽  
Nan Jiang
Keyword(s):  
Thermal Stress ◽  
Stress Distribution ◽  
Uniform Distribution ◽  
Inelastic Strain ◽  
Coupling Model ◽  
Power Module ◽  
Mechanical Coupling ◽  
Fem Method ◽  
Igbt Module ◽  
Solder Layer

Reliability of IGBT power module is one of the biggest concerns regarding wind power system, which generates the non-uniform distribution of temperature and thermal stress. The effects of non-uniform distribution will cause failure of IGBT module. Therefore, analysis of thermal mechanical stress distribution is crucially important for investigation of IGBT failure mechanism. This paper uses FEM method to establish an electrical-thermal mechanical coupling model of IGBT power module. Firstly, thermal stress distribution of solder layer is studied under power cycling. Then, the effects of initial failure of solder layer on the characteristic of IGBT module is investigated. Experimental results indicate that the strain energy density and inelastic strain are higher which will reduce reliability and lifetime of power modules.

scholarly journals Temperature conditions in the RBMK spent fuel pool in the event of disturbances in its cooling mode

2021 ◽  
Vol 7 (1) ◽  
pp. 9-13
Author(s):  
David A. Hakobyan ◽  
Victor I. Slobodchuk
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Maximum Temperature ◽  
Spent Fuel ◽  
Cooling Mode ◽  
Temperature Conditions ◽  
Fuel Assemblies ◽  
Spent Fuel Pool

The problems of reprocessing and long-term storage of spent nuclear fuel (SNF) at nuclear power plants with RBMK reactors have not been fully resolved so far. For this reason, nuclear power plants are forced to search for new options for the disposal of spent fuel, which can provide at least temporary SNF storage. One of the possible solutions to this problem is to switch to compacted SNF storage in reactor spent fuel pools (SFPs). As the number of spent fuel assemblies (SFAs) in SFPs increases, a greater amount of heat is released. In addition, no less important is the fact that a place for emergency FA discharging should be provided in SFPs. The paper presents the results of a numerical simulation of the temperature conditions in SFPs both for compacted SNF storage and for emergency FA discharging. Several types of disturbances in normal SFP cooling mode are considered, including partial loss of cooling water and exposure of SFAs. The simulation was performed using the ANSYS CFX software tool. Estimates were made of the time for heating water to the boiling point, as well as the time for heating the cladding of the fuel elements to a temperature of 650 °С. The most critical conditions are observed in the emergency FA discharging compartment. The results obtained make it possible to estimate the time that the personnel have to restore normal cooling mode of the spent fuel pool until the maximum temperature for water and spent fuel assemblies is reached.

Diamond-Coated Mechanical Seal Remaining Useful Life Prediction Based on Convolution Neural Network

2019 ◽  
Vol 34 (05) ◽  
pp. 2051007
Author(s):  
Zhibin Lin ◽  
Hongli Gao ◽  
Erqing Zhang ◽  
Weiqing Cao ◽  
Kesi Li
Keyword(s):  
Nuclear Power ◽  
Signal To Noise Ratio ◽  
Prediction Method ◽  
Degradation Process ◽  
Remaining Useful Life ◽  
Sensor Data ◽  
Mechanical Seal ◽  
Process Industries ◽  
Petroleum Chemical ◽  
Useful Life

Reliable remaining useful life (RUL) prediction of industrial equipment key components is of considerable importance in condition-based maintenance to avoid catastrophic failure, promote reliability and reduce cost during the production. Diamond-coated mechanical seal is one of the most critical wearing components in petroleum chemical, nuclear power and other process industries. Estimating the RUL is of critical importance. We consider the data-driven approaches for diamond-coated mechanical seal RUL estimation based on AE sensor data, since it is difficult to construct an explicit mathematical degradation model of seal. The challenges of this work are dealing with the noisy AE sensor data and modeling the degradation process with fluctuation. Faced with these challenges, we propose a pipeline method CDF-CNN to estimate the RUL for mechanical seal: WPD-KLD to raise the signal-to-noise ratio, novel CDF-based statistics to represent seal degradation process and CNN structure to estimate RUL. To acquire AE sensor data, several diamond-coated seals are tested from new to failure in three working conditions. Experimental results demonstrate that the proposed method can accurately predict the RUL of diamond-coated mechanical seal based on AE signals. The proposed prediction method can be generalized to other various mechanical assets.

Centrifugal Pump Leak-Free Technology Introduction and Its Applications in EPR Nuclear Power Plant

2010 ◽  
Author(s):  
Guohui Cong ◽  
Ling Zhang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Centrifugal Pump ◽  
Nuclear Power ◽  
Operating Conditions ◽  
Critical Conditions ◽  
Mechanical Seal ◽  
Centrifugal Pumps ◽  
Canned Motor ◽  
Magnetic Drive

Environmental protection requirement is more and more critical now, and it increases the request to prevent dangerous liquid to leak outside in nuclear power plant too. Centrifugal pumps are the most important active equipments in nuclear power plant, but there is a shaft clearance between rotor and stator of centrifugal pump. The shaft clearance can lead pumped fluid to the outside, so the environment may be polluted by the leakage. In some critical conditions such as transferring high radioactive fluid in the pump, the leakage shall be totally forbidden. So solutions have to be found to make centrifugal pumps totally leak-free for applications in nuclear power plant. Normally there are three leak-free technologies for centrifugal pumps: mechanical seal with auxiliary system, canned motor and magnetic drive. In this paper, all the three leak-free technologies and some of their applications in EPR 3rd generation PWR nuclear power plants are presented and discussed. The results show that in EPR nuclear power plant, canned motor pumps can be preferably used for strict environmental requirement of leak-free if the pump power and operating conditions are applicable. For other conditions, pumps with double mechanical seal can also be used with additional sealing water system support. For centrifugal pumps with magnetic drive are not so applicable in high pressure condition, and the safety aspect is weaker than canned motor pumps, generally they are not used in EPR nuclear power plant at present.

Analysis of Thermal Shock on Nuclear Power Station Pump

1998 ◽  
Author(s):  
Cao Qing ◽  
Wu Yimin ◽  
Zhang Zhimin
Keyword(s):  
Thermal Stress ◽  
Thermal Shock ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
Thermal Deformation ◽  
Power Station ◽  
Thermal Stress Field ◽  
Thermoelastic Equation ◽  
Thermal Shock Problem ◽  
Qualitative Discussion

In this paper, a heat conduction equation and a dynamic thermoelastic equation are briefly deduced and established based on Continuum Mechanics. First, an qualitative discussion is emphatically centered around the couple term and the dynamic term of the equation by means of the dimensional analysis and by considering the combination of the characteristics of the materials and of the thermal load effected on the nuclear power station pump under study. Second, formulations of the FEM for non-coupled heated equations and quasi-static thermoelastic equations are derived in this paper. Third, a half space thermal shock problem is used as a computational example in the highlighted research on the varying behavior of the dynamic thermal stress on the temperature slope. The conclusion of the paper provides reliable justification for applying the numerical method. Finally, the distribution and variety of the temperature field, the thermal stress field and the thermal deformation field at various transient moments on the pump are given.

An Unsteady Analysis on Thermal Stratification in the SCS Piping Branched Off the RCS Piping

2003 ◽  
Author(s):  
Kwang-Chu Kim ◽  
Man-Heung Park ◽  
Hag-Ki Youm ◽  
Sun-Ki Lee ◽  
Tae-Ryong Kim ◽  
...  
Keyword(s):  
Temperature Difference ◽  
Thermal Stratification ◽  
Nuclear Power ◽  
Cooling System ◽  
Numerical Study ◽  
Outer Wall ◽  
Maximum Temperature ◽  
Rear Side ◽  
Maximum Temperature Difference ◽  
Starting Point

A numerical study is performed to estimate on an unsteady thermal stratification phenomenon in the Shutdown Cooling System (SCS) piping branched off the Reactor Coolant System (RCS) piping of Nuclear Power Plant. In the results, turbulent penetration reaches to the 1st isolation valve. At 500sec, the maximum temperature difference between top and bottom inner wall in piping is observed at the starting point of horizontal piping passing elbow. The temperature of coolant in the rear side of the 1st isolation valve disk is very slowly increased and the inflection point in temperature difference curve for time is observed at 2700sec. At the beginning of turbulent penetration from RCS piping, the fast inflow generates the higher temperature for the inner wall than the outer wall in the SCS piping. In the case the hot-leg injection piping and the drain piping are connected to the SCS piping, the effect of thermal stratification in the SCS piping is decreased due to an increase of heat loss compared with no connection case. The hot-leg injection piping affected by turbulent penetration from the SCS piping has a severe temperature difference that exceeds criterion temperature stated in reference. But the drain piping located in the rear compared with the hot-leg injection piping shows a tiny temperature difference. In a viewpoint of designer, for the purpose of decreasing the thermal stratification effect, it is necessary to increase the length of vertical piping in the SCS piping, and to move the position of the hot-leg injection piping backward.

scholarly journals Multifield Coupling Model and Performance Analysis of a Hydrostatic Mechanical Seal

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5159
Author(s):  
Guiyue Kou ◽  
Xinghu Li ◽  
Yan Wang ◽  
Chunsen Tan ◽  
Kanran Zhou ◽  
...  
Keyword(s):  
Fluid Pressure ◽  
Coupling Model ◽  
Outer Diameter ◽  
Mechanical Seal ◽  
Design And Optimization ◽  
Seal Design ◽  
Mechanical Deformations ◽  
Deformation State ◽  
Inner Diameter ◽  
And Performance

A two-dimensional axisymmetric thermal-fluid-solid coupled mathematical model of a contact mechanical seal is established. The finite difference method is used to solve the control equations for the fluid pressure and temperature of the seal end face, and the finite element method is used to determine the thermal deformation state of the seal. The seal’s performance at different working speeds was studied and verified by experiments. The results show that under the combined actions of thermal and mechanical deformations, the seal end face forms a convergent leakage gap from the outer diameter to the inner diameter. The minimum film thickness is observed on the inner diameter side of the seal end face, and the highest end face temperature coincides with this location. With increasing working speed, the contact force at the inner diameter side increases, the temperature difference between the inner diameter and the outer diameter of the end face increases, and the leakage rate correspondingly increases. The numerical simulation results are in good agreement with the experimental results. The model and calculation method can be applied to other forms of mechanical seal design and optimization.

Evolution of Temperature Profiles during Stress-Induced Transformation in NiTi Thin Films

2013 ◽  
Vol 738-739 ◽  
pp. 287-291 ◽  
Author(s):  
Berthold Krevet ◽  
Viktor Pinneker ◽  
Magnus Rhode ◽  
Christoph Bechthold ◽  
Eckhard Quandt ◽  
...  
Keyword(s):  
Temperature Compensation ◽  
Room Temperature ◽  
Tensile Loading ◽  
Element Model ◽  
Maximum Temperature ◽  
Strain Rates ◽  
Temperature Profiles ◽  
Temperature Decrease ◽  
Time Resolved ◽  
Local Generation

This paper presents a time-resolved investigation of tensile loading induced temperature profiles in pseudoelastic NiTi thin film specimens. A finite element model for coupled mechanical and time dependent thermal analysis is presented that accounts for the different effects of local generation of latent heat and heat transfer. For strain rates larger than 0.24/s, the maximum temperature increases from room temperature to above 50 °C. Subsequent stress relaxation after temperature compensation results in a temperature decrease from room temperature down to -20 °C. The observed evolution of temperature profiles is in qualitative agreement with infrared thermography experiments on NiTi films fabricated by magnetron sputtering.

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