Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "pressure gradient" wg kryterium: Temat


Wyświetlanie 1-12 z 12
Tytuł:
Numerical analysis on the influence of the twisted blade on the aerodynamic performance of turbine
Autorzy:
Jin, J.
Wang, Z.
Cao, L.
Powiązania:
https://bibliotekanauki.pl/articles/258444.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
turbine
twisted blade
leakage vortex
pressure gradient
tip clearance
Opis:
With the gradual increase of the thermal power unit capacity, the inlet steam parameters and flow of the turbine also increase gradually, which causes considerable secondary flow loss. Therefore, studying the causes and distribution of secondary flow loss within the level is of great significance to effectively improve the stage internal efficiency of turbine. Take high-pressure stage moving blade of a turbine as the research object, and adopt the k-ωSST model, the SIMPLEC algorithm to numerically simulate the formation and development process of leakage vortex between the tip clearance of the positive bending twisted blade and its effect on the secondary flow of cascade passage. Results show that relative to the conventional twisted blade, the scope of influence of leakage vortex which the steam flow formed near the suction surface of positive bending twisted blade and the disturbance to passage mainstream become smaller, and the increase of tip clearance has weakened the „C” type pressure gradient of suction surface of the positive bending twisted blade, increased the thickness of the boundary layer at both ends of blades and the loss of the blade end.
Źródło:
Polish Maritime Research; 2016, S 1; 86-90
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
LES of converging-diverging channel flow with separation
Autorzy:
Kuban, L.
Elsner, W.
Tyliszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1943209.pdf
Data publikacji:
2010
Wydawca:
Politechnika Gdańska
Tematy:
LES
turbulent boundary layer
separation
channel flow
pressure gradient
Opis:
The paper presents the results of LES simulation of two different turbulent channels with inlet conditions corresponding to the Reynolds number Re =395. In both cases a varying pressure gradient was obtained by an adequate curvature of one of the walls. The first case is treated as a benchmark and is used to validate the numerical procedure. This case is characterized by the same cross-section area at the inlet and outlet and a bump of a smooth profile located on one of the walls designed to be identical to the one used in the experiment conducted at Laboratorie de Mecanique de Lille (LML) (Marquillie et al., 2008). The second case corresponds to the geometry which reproduces the real geometry of the turbomachinery test section of the Czestochowa University of Technology. The test section was created in such a way as to produce the pressure gradient which would correspond to the conditions present in the axial compressor blade channel. The shape of both channels produced initially favorable (FPG) and then adverse pressure gradients (APG), and in this way created conditions for boundary layer separation. Due to a reverse flow where the turbulence transport is dictated by the dynamics of the large-scale eddies such a case is well suited to demonstrate predictive features of the LES technique.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2010, 14, 3; 283-295
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric sensitivity of a CFD model concerning the hydrodynamics of trickle-bed reactor (TBR)
Autorzy:
Janecki, D.
Burghardt, A.
Bartelmus, G.
Powiązania:
https://bibliotekanauki.pl/articles/184944.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hydrodynamics
trickle-flow regime
pressure gradient
liquid holdup
phases interaction
CFD
hydrodynamika
gradient ciśnienia
Opis:
The aim of the present study was to investigate the sensitivity of a multiphase Eulerian CFD model with respect to relations defining drag forces between phases. The mean relative error as well as standard deviation of experimental and computed values of pressure gradient and average liquid holdup were used as validation criteria of the model. Comparative basis for simulations was our own data-base obtained in experiments carried out in a TBR operating at a co-current downward gas and liquid flow. Estimated errors showed that the classical equations of Attou et al. (1999) defining the friction factors Fjk approximate experimental values of hydrodynamic parameters with the best agreement. Taking this into account one can recommend to apply chosen equations in the momentum balances of TBR.
Źródło:
Chemical and Process Engineering; 2016, 37, 1; 97-107
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the diagnostic plot in estimation of the skin friction in turbulent boundary layer under an adverse pressure gradient
Autorzy:
Niegodajew, P.
Dróżdż, A.
Elsner, W.
Powiązania:
https://bibliotekanauki.pl/articles/38622693.pdf
Data publikacji:
2021
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
turbulent boundary layer
friction velocity
Clauser-chart
adverse pressure gradient
diagnostic plot
Opis:
The paper concerns the problem of determining friction velocity in wallbounded flows affected by an adverse pressure gradient (APG). In the work of Niegodajew et al. [22] the corrected Clauser chart method (CCCM) for such flow conditions was proposed. This approach utilises the mean velocity profiles and turbulence intensity profiles to accurately estimate the friction velocity. In another work, Drózdz et al. [27] presented a modified version of the diagnostic-plot scaling (DPS) which allows for direct reconstruction of turbulence intensity profiles based on the local mean velocity profile, even when the flow is affected by a strong pressure gradient. This paper is aimed at verifying whether, when combining both of these methods (i.e. DPS and CCCM), the friction velocity can be accurately determined for APG flow conditions and one can possibly take advantage from both methods. The analysis revealed that the new approach is able to predict the friction velocity with uncertainty less than 5% for all the considered cases for the Clauser–Rotta parameter β < 17. Lastly, DPS-CCCM was also confronted with two empirical approaches (from available literature) allowing for estimation of the friction velocity under APG conditions. The performance of DPS-CCCM was found to be better than the ones of two other empirical approaches.
Źródło:
Archives of Mechanics; 2021, 73, 2; 201-215
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient flow through a porous channel with ramped pressure gradient and velocity slip boundary condition
Autorzy:
Jha, Basant K.
Yunus, Zainab Sa'id
Powiązania:
https://bibliotekanauki.pl/articles/2174168.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ przejściowy
prędkość
ciśnienie
transient flow
velocity slip
ramped pressure gradient
Riemann-Sum approximation technique
Opis:
A transient flow formation of an incompressible fluid through a horizontal porous channel assuming a ramped pressure gradient is considered with the velocity slip boundary conditions. The flow is a laminar flow caused by ramped pressure gradient along the flow direction. The equation governing the flow is modeled, and solved by the Laplace transformation technique to obtain a semi-analytical solution under slip boundary conditions. It was noted that the flow velocity increases as the slip parameter is increased.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 1; 78--90
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On streamwise structures in boundary layer under adverse pressure gradient on inclined plate
Autorzy:
Uruba, V.
Prochazka, P.
Skala, V.
Powiązania:
https://bibliotekanauki.pl/articles/1955271.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska
Tematy:
boundary layer
adverse pressure gradient
inclined plate
proper orthogonal decomposition
POD
oscillation pattern decomposition
OPD
Opis:
The presented study is focused on experimental investigation of a boundary layer on a flat plate in an adverse pressure gradient. The flat plate is placed in a regular flow, the pressure gradient is generated by the plate inclination. The preceding studies deal with the structure of the wake behind the plate, the presented study concentrates on the flow structureclose to the suction surface of the plate. The dynamical behavior of the flow structures is studied in details with respect to the topology in the streamwise direction. In spite of the fact that thetime-mean flow field is close to 2D, more or less constant along the span, the instantaneous structures topology is fully 3D. Rather oblique structures are detected instead of those oriented in the streamwise direction. The patterns are travelling in the streamwise direction along the plate.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2018, 22, 3; 255--267
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of pressure gradient on convective heat transfer in a boundary layer flow of a Maxwell fluid past a stretching sheet
Autorzy:
Kashif, A. N.
Salah, F.
Sankar, D. S.
Izyan, M. D. N.
Viswanathan, K. K.
Powiązania:
https://bibliotekanauki.pl/articles/2106449.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
płyn Maxwell'a
przenoszenie ciepła
rozciąganie
pressure gradient parameter
convective heat transfer
Maxwell fluid
stretching sheet
Opis:
The pressure gradient term plays a vital role in convective heat transfer in the boundary layer flow of a Maxwell fluid over a stretching sheet. The importance of the effects of the term can be monitored by developing Maxwell’s equation of momentum and energy with the pressure gradient term. To achieve this goal, an approximation technique, i.e. Homotopy Perturbation Method (HPM) is employed with an application of algorithms of Adams Method (AM) and Gear Method (GM). With this approximation method we can study the effects of the pressure gradient [...], Deborah number [...], the ratio of the free stream velocity parameter to the stretching sheet parameter [...] and Prandtl number [...] on both the momentum and thermal boundary layer thicknesses. The results have been compared in the absence and presence of the pressure gradient term m. It has an impact of thinning of the momentum and boundary layer thickness for non-zero values of the pressure gradient. The convergence of the system has been taken into account for the stretching sheet parameter. The result of the system indicates the significant thinning of the momentum and thermal boundary layer thickness in velocity and temperature profiles.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 3; 104--118
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical Model of Oxygen Transport in Cornea
Autorzy:
Avtar, Ram
Seth, Deepti
Kumar, Aadesh
Powiązania:
https://bibliotekanauki.pl/articles/1159714.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Crank-Nicoloson method
Michaelis-Menten kinetics
Oxygentransport
Thomas algorithm
finite difference
metabolism
oxygen consumption
pressure gradient
Opis:
The aim of present work is the development of a quasi-steady state model for the time course concentration profile describing the oxygen diffusion and consumption in a multilayered corneal tissue and investigation of the effect of various model parameters on the oxygen concentration for open and closed eyes. A simple mathematical model for the oxygen transport in multilayered corneal tissue was developed using Fick’s law of diffusion, Michaelis-Menten kinetics of metabolism. A Crank-Nicolson finite difference scheme of the equation describing the oxygen diffusion and consumption was written, in which spatial diffusive terms of the equation were approximated by central differences while the temporal terms were approximated by average of forward and backward time differences. A system of linear equations obtained from the Crank-Nicholson finite differences schemes was solved by the Thomas Algorithm in which successive improve approximate results are obtained.
Źródło:
World Scientific News; 2018, 113; 169-184
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lengthwise finning surface as the method of influence on the flow separation in diffusers
Autorzy:
Zaryankin, A.
Rogalev, A.
Lisin, E.
Khudyakova, V.
Powiązania:
https://bibliotekanauki.pl/articles/122686.pdf
Data publikacji:
2017
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
diffuser
longitudinal pressure gradient
friction tension
velocity
finned surface
boundary layer
inertial force
flow separation
dyfuzor
warstwa graniczna
oddzielenie przepływu
siła tarcia
wzorzec przepływu
Opis:
The paper deals with the analysis of power factors acting within the boundary layer for different types of flow: convergent, gradientless and diffuser. Based on the considered formation mechanism of boundary layer separation, a hypothesis about the possible influence on structure and character of a separated flow by changing the gradient of the tangential stresses in the boundary layer was proposed. This impact is proposed to realize by means of the longitudinal finning of diffuser. Verification of the concept is performed on the basis of numerical flow investigation and available experimental data.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2017, 16, 1; 127-138
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ ciśnienia na konwersję paliw gazowych w strukturalnych reaktorach katalitycznych
Effect of pressure on conversion of gaseous fuels in structured catalytic reactors
Autorzy:
Budzianowski, W. M.
Powiązania:
https://bibliotekanauki.pl/articles/2071028.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
wysokie ciśnienie
reaktor strukturalny
gradient stężenia
high pressure
structured reactor
concentration gradient
Opis:
Zbadano wpływ wysokiego ciśnienia na konwersję i gradienty stężeniowe w procesie spalania i oksyformowania węglowodorów w strukturalnym reaktorze katalitycznym. Zdefiniowano, scharakteryzowano i wykorzystano w przykładzie wyrażenia S przydatne w analizie oporów dyfuzyjnych występujących w reaktorach strukturalnych wysokociśnieniowych. Zaproponowano metodykę nastawiania ciśnienia w reaktorach strukturalnych.
The paper investigated the effect of high pressure on conversion and concentration gradients in combustion and oxyforming of hydrocarbons in structured catalytic reactors. The terms S were defined, characterized and used for the analysis of transport resistances exhibited in high-pressure structured reactors. The method for pressure elevation in structured reactors was proposed.
Źródło:
Inżynieria i Aparatura Chemiczna; 2010, 1; 21-22
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elastic solutions based on the Mori-Tanaka scheme for pressurized functionally graded cylinder
Autorzy:
Eker, Mehmet
Yarımpabuç, Durmu
Yıldırım, Ali
Çelebi, Kerimcan
Powiązania:
https://bibliotekanauki.pl/articles/1839733.pdf
Data publikacji:
2020
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
FGM
functional gradient material
pseudospectral Chebyshev method
Mori-Tanaka homogenization
cylindrical pressure vessel
materiał funkcjonalnie gradientowy
cylindryczny zbiornik ciśnieniowy
pseudospektralna metoda Czebyszewa
metoda Czebyszewa
homogenizacja Mori-Tanaka
Opis:
In this paper, an elastic analysis of a thick-walled functionally graded cylinder subjected to internal pressure is examined. Material properties for the isotropic material are estimated to obey the Mori-Tanaka homogenization scheme through the thickness. The resulting two-point irregular boundary value problem is solved by the pseudospectral Chebyshev method that converts the boundary value problem to the system of equations, which can be solved by any appropriate decomposition method. Benchmark solutions are used to validate the method. The effect of the arbitrarily chosen volume fraction index is demonstrated for stress and displacement distributions. The effective stresses for different inner radius and volume fraction index are also discussed.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 4; 57-68
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elastic solutions based on the Mori-Tanaka scheme for pressurized functionally graded cylinder
Autorzy:
Eker, Mehmet
Yarımpabuç, Durmu
Yıldırım, Ali
Çelebi, Kerimcan
Powiązania:
https://bibliotekanauki.pl/articles/1839749.pdf
Data publikacji:
2020
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
FGM
functional gradient material
pseudospectral Chebyshev method
Mori-Tanaka homogenization
cylindrical pressure vessel
materiał funkcjonalnie gradientowy
cylindryczny zbiornik ciśnieniowy
pseudospektralna metoda Czebyszewa
metoda Czebyszewa
homogenizacja Mori-Tanaka
Opis:
In this paper, an elastic analysis of a thick-walled functionally graded cylinder subjected to internal pressure is examined. Material properties for the isotropic material are estimated to obey the Mori-Tanaka homogenization scheme through the thickness. The resulting two-point irregular boundary value problem is solved by the pseudospectral Chebyshev method that converts the boundary value problem to the system of equations, which can be solved by any appropriate decomposition method. Benchmark solutions are used to validate the method. The effect of the arbitrarily chosen volume fraction index is demonstrated for stress and displacement distributions. The effective stresses for different inner radius and volume fraction index are also discussed.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 4; 57-68
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies