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1

Preliminary specification of the dry ice blasting converging-divergent nozzle parameters basing on the standard (analytical) methods

Mikołajczak A., Krawczyk P., Stępień M., Badyda K.

Rynek Energii

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2018

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Nr 4

91--96

EN

Pollution can be a serious problem in industry, that is why various cleaning methods were developed. The dry-ice blasting is one of them, which can be easily implemented in a different applications, i.e. electric industry. In this method dry, compressed air with the solid CO2 particles hits the cleaned surface. The pollution is removed by supercooling and crushing due to the particles strikes and local volume growth, caused by the dry ice sublimation. To provide the proper air-particles mixture parameters, converging-divergent nozzles are used. The geometry of the nozzle can have the crucial influence on the mixture parameters and the cleaning efficiency. Among the most important nozzles parameters the opening angle, critical cross section and the shape of the outlet were determined. These specification can be used during the further work as the guidelines to the CFD modeling.

PL

Zanieczyszczenia przemysłowe mogą stanowić poważny problem eksploatacyjny, dlatego opracowano i powszechnie stosuje się różne metody czyszczenia. Jedną z nich jest czyszczenie mieszaniną suchego lodu i powietrza. Metoda ta może być łatwo wdrożona w różnych zastosowaniach, np. przemyśle elektro-energetycznym. W opisywanym rozwiązaniu suche, sprężone powietrze z cząsteczkami stałego CO2 trafia na czyszczoną powierzchnię. Zanieczyszczenie usuwane jest przez przechłodzenie i pękanie warstwy brudu w wyniku uderzenia cząstek o dużej prędkości i lokalnego wzrostu objętości, spowodowanego sublimacją suchego lodu. Aby zapewnić prawidłowe parametry mieszaniny suchy lód-powietrze, stosuje się dysze zbieżno-rozbieżne. Geometria dyszy może mieć decydujący wpływ na parametry mieszanki i skuteczność czyszczenia. Wśród najważniejszych parametrów dysz wymienić można kąt rozwarcia, przekrój krytyczny oraz kształt przekroju wylotowego. Opracowane wytyczne mogą zostać wykorzystane podczas dalszej pracy do stworzenia modelu CFD, umożliwiającego ostateczną weryfikację kształtu kanału przepływowego dyszy.

2

Efekt odparowania fazy ciekłej na fali uderzeniowej w przepływach okołodźwiękowych powietrza wilgotnego z kondensacją pary wodnej

Szymański A., Dykas S., Majkut M.

Modelowanie Inżynierskie

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2015

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T. 26, nr 57

54--62

PL

W pracy przeprowadzono analizę numeryczną przepływu transonicznego powietrza atmosferycznego, które ze swojej natury zawsze zawiera pewną ilość pary wodnej, w dyszach de Lavala. Do obliczeń wybrano dyszę de Lavala o dużej prędkości ekspansji i połówkową dyszę zbieżno-rozbieżną o znacznie mniejszej prędkości ekspansji. Obliczenia przeprowadzono za pomocą własnego kodu CFD, w którym zamodelowano powstawanie fazy ciekłej w wyniku kondesacji spontanicznej pary wodnej zawartej w powietrzu wilgotnym. W obliczeniach przepływu okołodźwiękowego uwzględniono również obecność prostopadłej fali uderzeniowej w części naddźwiękowej dyszy w celu analizy efektu odparowani fazy ciekłej.

EN

This paper presents a numerical analysis of the atmospheric air transonic flow through de Laval nozzles. By nature, atmospheric air always contains a certain amount of water vapour. The calculations were made using a Laval nozzle with a high expansion rate and a convergent-divergent (CD) “half-nozzle”, referred to as a transonic diffuser, with a much slower expansion rate. The calculations were performed using an in-house CFD code. The computational model made it possible to simulate the formation of the liquid phase due to spontaneous condensation of water vapour contained in moist air. The transonic flow calculations also take account of the presence of a normal shock wave in the nozzle supersonic part to analyse the effect of the liquid phase evaporation.

3

Vibrations and stability of a biself-excited surface structure in supersonic flow subjected to a follower force

Dżygadło Z., Nowotarski I., Olejnik A.

Journal of Technical Physics

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2003

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Vol. 44, no 4

349-362

EN

A surface structure in supersonic flow having a deformable support and subjected to a follower compressing force, which preserves its direction tangential to the deformed surface, is a biself-excited system enclosing two independent physical factors being the reason of self-excited vibrations. In the paper, a study of vibrations and stability of such a structure is presented using the example of a rectangular plate in one-side supersonic flow subjected to a follower force. The plate is considered under the assumption that the conditions of rigid support are satisfied at the plate edges parallel to the unperturbed flow direction. One of the remaining edges is clamped, while the second one has a deformable support. For comparison, the results of analysis in the case of a plate of finite length and infinite width are also presented. A number of numerical calculations have been performed. The analysis indicates a variety of phenomena resulting from simultaneous action of the two independent factors decisive for self-excitation of the structure under consideration.

4

Experimental research on development of the controllable disturbances in the wake at supersonic flow around the plate

Lysenko V. I., Kosinov A. D., Yermolaev Yu. G.

Archives of Mechanics

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2003

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Vol. 55, nr 3

243-256

EN

The development of the artificial disturbances in the boundary layer on the flat part of a plate, the boundary layer on the opposite wedge (model stern) behind a fan of expansion waves and the wake was investigated at Mach number 2.

5

Influence of a heterogeneous combustion system in near wake of bodies of revolution on its drag force in supersonic flow

Glagolev A., Zubkov A., Suhanovskaya L.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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2001

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nr 11

81-86

EN

We had used non-conventional methods for heat and mass transfer determination to axisymmetric bodies in the base pressure and drag force control. The experiments were conducted in supersonic flow for Mach numbers within the range 1.15

6

Nonlinear, regular and chaotic vibrations of an airfoil with a trailing and edge flap in supersonic flow

Dżygadło Z., Nowotarski I., Olejnik A.

Journal of Technical Physics

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2000

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Vol. 41, no 3

219-229

EN

An airfoil in supersonic flow, having deformable nonlinear supports, is an aeroelastic system for which various types of instability, bifurcations and regular or chaotic motions can appear. The airfoil has three degrees of freedom - that is, plunge displacement, angle of pitch and angle of flap deflection. The stiffness force and moments for all those motions are assumed to be nonlinear ones. The airfoil is subjected to the pressure difference produced by its motion in supersonic flow. Stability and bifurcations occurring in the system, limit cycles of self-excited vibrations and regions of regular or chaotic motions have been investigated. The effect of some parameters of the system on the course of linear and nonlinear vibrations has been studied.

7

Nonlinear, regular and chaotic vibrations of a plate in supersonic flow

Dżygadło Z., Nowotarski I., Olejnik A.

Journal of Technical Physics

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2000

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Vol. 41, no 4

361-374

EN

Aeroelasticity of surface structures in supersonic flow is a domain which involves various linear and nonlinear vibrations, static and dynamic instabilites and limit cycle motions (cf. [1-4). Various types of bifurcations and regular or chaotic motions can appear depending on the values of parameters of the system under investigation [3-11]. In this paper, nonlinear bending vibrations of a plate of finite length and infinite width in supersonic flow are considered under the assumption that a nonlinear in-plane compressing force is acting in the plate. The dynamic pressure difference produced by the plate motion in gas stream is determined on the basis of the potential theory of supersonic flow [1, 2]. Finally, we obtain a nonlinear partial integro-differential equation describing the motion of the structure under investigation. The solution of this equation is obtained in the form of a series of normalised eigenfunctions of the self-adjoint boundary-value vibration problem of the same plate in the vacuum. Making use of the Galerkin method, we then obtain a set of nonlinear ordinary differential equations which can be analysed by means of numerical methods. Types of bifurcations occurring in the problem are investigated, limit cycles of self-excited vibrations and regions of regular and chaotic motions can be determined.

8

Regular and chaotic vibrations of an airfoil in supersonic flow

Dżygadło Z., Nowotarski I., Olejnik A.

Journal of Technical Physics

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1999

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Vol. 40, no 1

117-143

EN

An airfoil in supersonic flow, having deformable nonlinear supports, is an aeroelastic system for which various types of bifurcation and regular or chaotic motions can appear. The airfoil has two degrees of freedom - that is, plunge dispalcement and angle of pitch displacement. The stiffness force and moment for those motions are assumed to be nonlinear ones. The airfoil is subjected to the pressure difference produced by its motion in supersonic flow. Types of bifurcation occurring in the system, limit cycles of self excited vibrations and regions of regular or chaotic motions have been investigated. The effect of some parameters of the system on the course of nonlinear vibrations has been studied.

9

Modification of the triple shock waves configuration theory in the problem of an oblique shock wave reflection at a rigid surface

Łęgowski Z.

Journal of Technical Physics

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1999

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Vol. 40, no 4

457-474

EN

A theoretical method of determining the triple-point trajectory angle x of the irregular wave configuration near the reflecting surface has been worked out. A systematic analysis of the modified triple shock wave configuration theory is performed in the oblique shock wave reflection problem at a rigid wall, and is then compared to the elementary Mach-type reflection theory, with regard to its modification given in [1]. A different influence on the flow parameters of the corner signals in the regions behind the reflected r and the Mach m waves separated by the contact discontinuity cd has been pointed out.