• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3438-3448
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• 2021

Dynamic seals are one of the critical components of Absorber Rod Drive Mechanism of Fast Breeder Reactors, requiring separate experimental development. Their significance can't be overemphasized considering that the availability and re-usability of Control Rod Drive Mechanisms of Fast Breeder Test Reactor is governed by the failure rate of dynamic seals (bellows). For prototype and subsequent Fast Breeder Reactors in India, choice of the dynamic seal is changed to an in-house designed & developed labyrinth type V-ring seal. The present work is related to the numerical investigations carried out to gain insights into the sealing mechanism and the thermal behaviour of these seals. The results indicate that the seal geometry is very important for obtaining optimum performance. By changing the geometry of the present seal, performance enhancement by more than 50% in important indices is obtained. Further, the results point out that caution shall be exercised when the seal material & its operating temperature are changed. Also, the numerical model developed in this study will be useful for developing more robust dynamic seals in future.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.537-545
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• 2013

The elastic recovery of a metal seal is a factor that can be used to assess its sealing performance. In this study, a compliant mechanism topology optimization has been performed to find a structure of a metal O-ring seal that can maintain excellent sealing performance with a maximized elastic recovery over extended operation. An evolutionary structural optimization (ESO) was used as a topology optimization algorithm with two different types of objective functions considering both flexibility and stiffness. In particular, a circular design domain was adopted to consider the outer shape of the metal O-ring seal. The elastic recovery of the optimal topology was calculated and compared to that of a commercial product.

• Tribology and Lubricants
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• v.14 no.2
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• pp.49-56
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• 1998

The thermal deformation of the contact seal components has been analyzed using the finite element method. The temperature distributions, the thermal deformations and contact stresses are solved numerically for the contact surface with wear coning effects. The thermal deformation is always shown to distort the sealing surface along the radius of the seal ring. The results show that the deformations of inner radius side are significant compared with those of outer radius. Thus, the thermal deformation due to thermal heatings may promote the coned face wear or wear related thermal cracks at the contacting face of the seal ring component.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.149-158
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• 1998

The thermal deformation of the contact seal components has been analyzed using the finite element method. The temperature distributions, the thermal deformations and contact stresses are solved numerically for the contact surface with wear coning effects. The thermal deformation is always shown to distort the sealing surface along the radius of the seal ring. The results show that the deformations of inner radius side are significant compared with those of outer radius. Thus, the thermal deformation due to thermal heatings may promote the coned face wear or wear related thermal cracks at the contacting face of the seal ring component.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.341-347
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• 2005

To perform a cryogenic development test for Tribo-elements in a turbopump, a cryogenic bearing and seal test facility (BSTF) is designed and currently under construction in KARI. The working fluid is liquid nitrogen operating at a temperature $-197^{\circ}C$. The maximum operating pressure and volume flow rate of BSTF are 100 bar and 10 liters per second, respectively. The development tests of floating ring seals, inter-propellant seals (IPS) and cryogenic ball bearings in a turbopump will be performed using the BSTF. This paper briefly described design requirements and procedures of BSTF.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.209-212
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• 2004

The O-ring seal is a usual component part in various mechanical apparatuses for sealing that makes efficient performance of the equipments. The sealing performance of 0-ring is effected in environments of the O-ring seal, like that applied pressures, working temperatures, interferences and materials. In this paper, an pressurized, NBR O-ring is calculated by experimental methods and analysed numerically using the MARC finite element program. The calculated experimental and FEM results showed that the Contact force O-ring decreases as a function of temperature.

• Journal of Biosystems Engineering
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• v.17 no.4
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• pp.305-313
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• 1992

Dynamic seals have been continue to be one of the major technical problems facing stirling engine designers. Most of the modern engines use some version of the dry ring seal for piston and displacer seals. Friction power losses associated with seals are typically several percent of gross output power, with piston ring seals usually being the main contributor. Much effort has been expended to develop the seal mechanism of piston, but the performance of these seal devices is very poor. This study was conducted to examine the efficiency of the various types of the trial-made piston seal mechanism with reference to leakage of working fluid and friction losses. This paper described the successful hardware implementation of a stainless steel bellows element in stirling engine application with test data in power performance. The indicated power by use of the bellows was more than two times as that by use of the piston ring types. As the result of this study, bellows was provide as a reliable and efficient seal mechanism for any stirling engine application.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.329-336
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• 2004

The lock-up position of the floating ring seal affects the leakage flowrate and the stability. And it is changed depending on the operating and geometry condition. In this paper, the leakage flowrate and stability with change of the height and length were investigated by theoretical analysis and experiment. The parameter of the height and length is expressed to the b and L. The decreasing of the b resulted in the increasing of equivalent whirl frequency ratio in the experimental result at the low speed and high pressure not such as theoretical analysis. As the L increased the leakage flowrate decreased and stiffness and direct damping coefficient increased in the experimental result. That was similar to the theoretical analysis.

• The KSFM Journal of Fluid Machinery
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• v.7 no.6 s.27
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• pp.21-27
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• 2004

The floating ring seal has an advantage to find the optimum position by itself, which is used in the turbo pump of a liquid rocket. The main purpose of seals is to reduce the leakage. Especially, seals of the turbo pump for the liquid rocket engine are operated under the serious conditions such as high pressure above 10 MPa, very low temperature about $-180^{\circ}C$ and high rotating speed above 25,000 rpm. So, rotordynamic stability is very important for the system stability. In this paper, the leakage and dynamic characteristics of floating ring seals were investigated by a experimental and analytical method. The theoretical results of the leakage performance for the floating ring seal showed much higher than that of experimental results. On the other hand, the results of stiffness and damping characteristics showed similarity each other. As the shaft speed was increasing, the whirl frequency ratio was increased in the experimental results.

• Tribology and Lubricants
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• v.19 no.1
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• pp.9-14
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• 2003

The sealing performance of an elastomeric O-ring using the double layered material has been analyzed fer the contact stress behaviors that develop between the O-ring seal and the surfaces with which it comes into contact. The leakage of an O-ring will occur when the pressure differential across the seal Just exceeds the initial (or static) peak contact stress. The contact stress behaviors that develop in compressed O-rings, in common case of dovetail grooved geometry, are investigated using the finite element method. The FE analysis includes material hyperelasticity and axisymmetry. The computed FEM results show that the contact stress behaviors are related to the ratio of diameter between the inner ring and the outer ring, and the temperature of vacuum chamber.