Applied Mechanics and Materials Vol. 630

Abstract: Currently, there are many designs of sealing devices pumps and turbines. However, not all of them have found widespread application. Most commonly used in the industry to non-contact seal minimum positive clearance. These include gap, labyrinth, celled, grooved, screw, etc. The article describes the modeling of the working fluid in sealing gap using Ansys CFX through the gaps, grooved and screw seals, comparison values leaks.)

Abstract: The paper studies the labyrinth seals of centrifugal compressor profit-proved stages using modern methods of numerical and physical modeling of the centrifugal compressor stages. A series of studies of the effect of operational and geometrical parameters on the maze, namely the quantities of the packed differential pressure, speed, fluid, geometric parameters of the seal, the magnitude of the eccentricity and radial clearance swirl flow at the inlet of a seal, etc. The technique of physical modeling seal has been specified. Research was conducted in two phases: numerical simulation using complex software Flow Vision and receiving data on a universal test bench to study the labyrinth seals.. A three-dimensional model of the labyrinth seal has been created, its verification by "known data has been held.. Integral characteristics in the form of distribution of flow velocities and pressures, flow visualization were obtained. Results of studies made ​​it possible to refine the workflow and introduce amendments to the known calculation formula for a more accurate calculation of leakage through the seal, subject to a number of additional factors that were not previously taken into account

Abstract: The authors have developed a method of calculating the non-linear elastic force that arises in the clearance seal of a finite length. The authors have analysed the force impact on the dynamics of the rotor of a centrifugal machine.

Abstract: In this paper the methods of static and dynamic analysis of the closing rotor balancing device of the multistage centrifugal pump are represented. On an example of the feed pump PE 600-300 static and dynamic characteristics are determined. Defined the resonance frequencies and investigated stability of the system “pump rotor – automatic balancing device – pressure difference regulator”. The dependence for the pressure difference and conditions to ensure reliable operation of the locking rotor balancing device are determined.

Abstract: Mechanical face seals are usually described as contacting seals because their faces are in partial contact during static conditions. However, many experiments demonstrated that this contact is not maintained during operation. Indeed a full fluid film can separate the seal surfaces leading to lower friction and wear. In this paper, the mechanisms of lubrication taking place at the seal interface are reviewed and analyzed through simulations and experiments. It is shown that several lubrication regimes can be experienced, depending on the operating conditions and on the seal design. At low speed values the lubrication regime is mixed and turns to hydrodynamic lubrication regime when the speed is increased. At higher rotation velocity, the dissipated power generates thermal gradients and leads to thermally controlled lubrication regime. The transition between the lubrication regimes is also discussed and dimensionless parameters controlling the transition are proposed.

Abstract: Mathematical background for static analysis of impulse gas seal is created in current paper. It includes evaluation of gap and flow rates of gas in turbocompressors. This paper consists of two parts. In the first one all logical steps of creation of the theoretical model for impulse gas seals are given. It should be mentioned, that they are valid for isothermal steady process which is observed here. The verification of derived theory is shown in the second part on a calculation example.

Abstract: The paper describes the construction and operating principle of the non-contacting impulse face seal. A mathematical model of the impulse seal was formulated. The method of control of the opening force by change of the cavity volume within sealing gap was described. The results obtained from the numerical calculations prove that the effect of the cavity volume on the axial vibrations of the flexibly mounted ring.

Abstract: Flanged connections are widely used in pipelines of various technical systems. Task of reducing the consumption of materials pipelines , ensuring their long-term tightness is highly relevant for shipbuilding , aviation and space technology and other mashinebuilding. In this paper, the task of deliberately reducing torque fasteners flange connection at build pipelines to ensure the initial tightness of the connection , reducing the weight of the pipeline , the alignment of the stress- strain state of the compound and determining the residual torque fasteners, providing connections for leaks. With decreasing torque fasteners ( intentional or natural ) will be sealed flanged if the remaining torque is sufficient to compensate for the pressure in the pipeline and prevent shear movement of the flange and gasket relative to each other . Found that the flange connection remains sealed with natural and deliberate reduction torque fasteners to 75-80 % compared to the initial .Sealing flange connections using technology and standard fastenings to reduce their weight by 10-50 %, and the replacement of flanges and pipe material - a whole lot of pipelines at 30-65 %.

Abstract: The paper deals with new indirect methods of leakage flow rate measurement in compressed air pipelines. In this method the measurement equipment has branch connection to the pipeline. The measurement method consists in determining the relation between air leakage flow rate in pipeline and the controlled air flow rate through adjustable throttle valve. Compressed air leakage flow rate in pipeline is calculated on the basis of pressure ratio measurements in two time intervals - during leakage without the controlled flow and with the controlled flow in branch line. The controlled air flow through the throttle valve is directly measured by flow meter.

Abstract: The oil lip seal operation is affected by the kinematics of the relative motion of the lip surface with respect to the shaft during both assembly and operation. Moreover, the variable position of the contact area along the sealing edge determines the contact pressure distribution and hence the wear rate of the lip.