On the surface vis impressa caused by a fluid-solid contact

Badur, Janusz; Ziółkowski, P.; Zakrzewski, W.; Sławiński, Daniel; Banaszkiewicz, M.; Karczmarczyk, O; Kornet, Sebastian

doi:10.1201/b15684-11

Cited by 5 publications

(9 citation statements)

References 1 publication

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“…Therefore, we can define a relation ratio between the internal and external friction with a dimension-less coefficient λ vis and two lengths of velocity slip: l 1v and l 2v ( Table 1). Having measured the internal property of friction, one can connect the external properties of friction at the Stokes boundary layer by appropriate closures written for λ vis , l 1v , and l 2v , respectively [55][56][57][58]. Table 1.…”

Section: Neoclassical Boundary Conditionsmentioning

confidence: 99%

Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics

2020

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The seminal Navier–Stokes equations were stated even before the creation of the foundations of thermodynamics and its first and second laws. There is a widespread opinion in the literature on thermodynamic cycles that the Navier–Stokes equations cannot be taken as a thermodynamically correct model of a local “working fluid”, which would be able to describe the conversion of “heating” into “working” (Carnot’s type cycles) and vice versa (Afanasjeva’s type cycles). Also, it is overall doubtful that “cycle work is converted into cycle heat” or vice versa. The underlying reason for this situation is that the Navier–Stokes equations come from a time when thermodynamic concepts such as “internal energy” were still poorly understood. Therefore, this paper presents a new exposition of thermodynamically consistent Navier–Stokes equations. Following that line of reasoning—and following Gyftopoulos and Beretta’s exposition of thermodynamics—we introduce the basic concepts of thermodynamics such as “heating” and “working” fluxes. We also develop the Gyftopoulos and Beretta approach from 0D into 3D continuum thermodynamics. The central role within our approach is played by “internal energy” and “energy conversion by fluxes.” Therefore, the main problem of exposition relates to the internal energy treated here as a form of “energy storage.” Within that context, different forms of energy are discussed. In the end, the balance of energy is presented as a sum of internal, kinetic, potential, chemical, electrical, magnetic, and radiation energies in the system. These are compensated by total energy flux composed of working, heating, chemical, electrical, magnetic, and radiation fluxes at the system boundaries. Therefore, the law of energy conservation can be considered to be the most important and superior to any other law of nature. This article develops and presents in detail the neoclassical set of Navier–Stokes equations forming a thermodynamically consistent model. This is followed by a comparison with the definition of entropy (for equilibrium and non-equilibrium states) within the context of available energy as proposed in the Gyftopoulos and Beretta monograph. The article also discusses new possibilities emerging from this “continual” Gyftopoulos–Beretta exposition with special emphasis on those relating to extended irreversible thermodynamics or Van’s “universal second law”.

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Section: Neoclassical Boundary Conditionsmentioning

confidence: 99%

Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics

2020

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“…Another aspect is the interaction of fatigue and creep [12,13]. The new computational tools such FSI (Fluid Solid Interaction) allow determining the fluid -solid interactions [3,6,16,18]. Of particular importance is the transfer of information on the interface (with working medium -construction) which represents the connection, and at the same time the boundary condition, between the CSD (Computational Solid Dynamic) and CFD (Computational Fluid Dynamic).…”

Section: Introductionsmentioning

confidence: 99%

“…After analysing the load status of individual devices of the cycle, it should be noted that particularly vulnerable to variable parameters of steam are boilers [4][5][6][7][8][9], then valves [10] and finally the first stages of the turbine [11][12][13][14][15]. To face these threats, it is necessary to increase the safety of operation of energy cycles including steam turbine type 18K370 [1][2][3]. The work regimes for load of control stage are different, so we have to rely upon more accurate calculation tools [3,16] including predicting further safe operation of steam turbine rotors after the calculated working time [14] as well as the increased expenditure and even entry into resonance resulting from the non-stationary operating conditions [17,18].…”

Section: Introductionsmentioning

confidence: 99%

“…To face these threats, it is necessary to increase the safety of operation of energy cycles including steam turbine type 18K370 [1][2][3]. The work regimes for load of control stage are different, so we have to rely upon more accurate calculation tools [3,16] including predicting further safe operation of steam turbine rotors after the calculated working time [14] as well as the increased expenditure and even entry into resonance resulting from the non-stationary operating conditions [17,18]. Another aspect is the interaction of fatigue and creep [12,13].…”

Section: Introductionsmentioning

confidence: 99%

“…Selected results of the analysis of the strength of CSD (Computational Solid Dynamic) and the nature of the flow in different operating regimes -thanks to CFD (Computational Fluid Dynamic) analysis have been included. We have also briefly discussed the way of lifecycle management of individual elements [2,3]. The presented actions could be considered satisfactory, and improve the safety of operating steam turbines of type 18K370.…”

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confidence: 99%

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Issues to improve the safety of 18K370 steam turbine operation

Bzymek¹,

Badur

Ziółkowski

2017

E3S Web Conf.

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Abstract. The paper presents the process of improving the safety and reliability of operation the 18K370 steam turbines Opole Power Plant since the first failure in 2010 [1], up to install the on-line monitoring system [2]. It shows how the units work and how to analyse the contol stage as a critical node in designing the turbine. Selected results of the analysis of the strength of CSD (Computational Solid Dynamic) and the nature of the flow in different operating regimes -thanks to CFD (Computational Fluid Dynamic) analysis have been included. We have also briefly discussed the way of lifecycle management of individual elements [2,3]. The presented actions could be considered satisfactory, and improve the safety of operating steam turbines of type 18K370.

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