Load and loss for high-speed lubrication flows of pressurized gases between non-concentric cylinders

2019 ◽  
Vol 867 ◽  
pp. 1-25 ◽  
Author(s):  
S. Y. Chien ◽  
M. S. Cramer
Keyword(s):  
High Speed ◽  
Outer Cylinder ◽  
Perturbation Expansion ◽  
Present Theory ◽  
Navier Stokes ◽  
Exact Relation ◽  
Lubrication Equation ◽  
Speed Flow ◽  
Concentric Cylinders ◽  
Large Speed

We examine the high-speed flow of pressurized gases between non-concentric cylinders where the inner cylinder rotates at constant speed while the outer cylinder is stationary. The flow is taken to be steady, two-dimensional, compressible, laminar, single phase and governed by a Reynolds lubrication equation. Approximations for the lubricating force and friction loss are derived using a perturbation expansion for large speed numbers. The present theory is valid for general Navier–Stokes fluids at nearly all states corresponding to ideal, dense and supercritical gases. Results of interest include the observation that pressurization gives rise to large increases in the lubricating force and decreases in the fluid friction. The lubrication force is found to scale with the bulk modulus. Within the context of the Reynolds equation an exact relation between total heat transfer and power loss is developed.

scholarly journals High-Speed Flow in an Annular Cascade With Tip Clearance: Numerical Investigation

1998 ◽  
Author(s):  
E. S. Politis ◽  
K. C. Giannakoglou ◽  
K. D. Papailiou
Keyword(s):  
High Speed ◽  
High Reynolds Number ◽  
Tip Clearance ◽  
Navier Stokes ◽  
High Speed Flow ◽  
Numerical Predictions ◽  
Simulated Experiment ◽  
Speed Flow ◽  
High Reynolds ◽  
Annular Cascade

The high-speed flow in an annular cascade with two tip clearance sizes is numerically modeled using a Navier-Stokes solver and the high-Reynolds-number k-ε turbulence model. The numerical predictions should be regarded as complementary to the experimental work conducted in the NTUA annular cascade facility, designed for studying tip-clearance effects in compressor cascades. In the numerically simulated experiment, the stationary blades are mounted on the casing and the tip clearance is formed between them and the spinning hub. The purpose of the present paper is to scrutinize flow trends identified during the measurements and elucidate the flow patterns in the blade passage for rotating and stationary hub.

Hypersonic Swirling Flow past Blunt Bodies

1973 ◽  
Vol 24 (4) ◽  
pp. 241-251 ◽  
Author(s):  
Roger Smith
Keyword(s):  
High Speed ◽  
Swirling Flow ◽  
Pressure Coefficient ◽  
Density Ratio ◽  
Perturbation Expansion ◽  
The Body ◽  
Constant Density ◽  
Flow Past ◽  
Speed Flow ◽  
Blunt Bodies

SummaryThe effect of swirl on the high speed flow past blunt bodies is analysed by assuming constant density in the region between the shock wave and the body. For small swirl the stand-off distance is only slightly affected, but it is shown that there is a critical value of the swirl parameter which, if exceeded, will cause a jump in the position of the shock. This is demonstrated by solving the full constant-density equations for the flow past a sphere and by a perturbation expansion in powers of the density ratio across the shock for a more general body shape. The perturbation solution shows that the pressure coefficient on the body is constant at the critical swirl number.

Computations of the Compressible Multiphase Flow Over the Cavitating High-Speed Torpedo

2003 ◽  
Vol 125 (3) ◽  
pp. 459-468 ◽  
Author(s):  
F. M. Owis ◽  
Ali H. Nayfeh
Keyword(s):  
High Speed ◽  
Multiphase Flows ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Multiphase System ◽  
System Of Equations ◽  
Cavitating Flows ◽  
Navier Stokes Equations ◽  
Compressible Multiphase Flow ◽  
Speed Flow

For high-speed cavitating flows, compressibility becomes significant in the liquid phase as well as in the vapor phase. In addition, the compressible energy equation is required for studying the effects of the propulsive jet on the cavity. Therefore, a numerical method is developed to compute cavitating flows over high-speed torpedoes using the full unsteady compressible Navier-Stokes equations. The multiphase system of equations is preconditioned for low-speed flow computations. Using the mass fraction form, we derive an eigensystem for both the conditioned and the nonconditioned system of equations. This eigensystem provides stability for the numerical discretization of the convective flux and increases the convergence rate. This method can be used to compute single as well as multiphase flows. The governing equations are discretized on a structured grid using an upwind flux difference scheme with flux limits. Single as well as multiphase flows are computed over a cavitating torpedo. The results indicate that the preconditioned system of equations converges rapidly to the required solution at very low speeds. The theoretical results are in good agreement with the measurements.

Centrifugal instabilities of circumferential flows in finite cylinders: nonlinear theory

1980 ◽  
Vol 372 (1750) ◽  
pp. 317-356 ◽  
Keyword(s):  
Vortex Flow ◽  
Outer Cylinder ◽  
Perturbation Expansion ◽  
Direct Consequence ◽  
Finite Amplitude ◽  
Taylor Vortex ◽  
Taylor Vortex Flow ◽  
Concentric Cylinders ◽  
Axisymmetric Disturbances ◽  
Finite Cylinders

In an earlier paper, Blennerhassett & Hall (1979) investigated the linear stability of the flow between concentric cylinders of finite length. The inner cylinder was taken to rotate, while the outer cylinder was fixed. Furthermore, the end walls rotated such that the flow was purely circumferential. In this paper the finite amplitude development of the unstable disturbances to the flow is considered. It is found that the usual perturbation expansion of nonlinear stability theory must be modified if the cylinders are not infinitely long. The bifurcation to a Taylor vortex flow in finite cylinders is shown to be two-sided. The latter effect is shown to be a direct consequence of the finiteness of the cylinders and by taking the cylinders to be very long, we recover the results obtained previously for the infinite problem. The interaction of the two most dangerous modes of linear theory is also investigated. For certain values of the length of the cylinders the initial finite amplitude Taylor vortex flow is shown to become unstable to another class of axisymmetric disturbances. The effect of perturbing the end conditions towards the no-slip conditions appropriate to most experimental configurations is also discussed. Some discussion of the instability problem in very long cylinders with fixed ends is given.

Simulation the formation process of boiling water flow during depressurization of a high pressure vessel using OpenFoam open source

2017 ◽  
Vol 12 (2) ◽  
pp. 169-173 ◽  
Author(s):  
R.Kh. Bolotnova ◽  
V.A. Korobchinskaya
Keyword(s):  
Open Source ◽  
High Speed ◽  
Numerical Study ◽  
Mass Conservation ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Speed Flow ◽  
Initial Stage ◽  
Calculation Results ◽  
Water Outflow

A numerical study of the initial stage of water outflow process through a thin nozzle from a supercritical state in a two-dimensional axisymmetric setting is performed using the OpenFOAM software open source with the sonicFoam solver. The mathematical model of sonicFoam solver includes the equation of mass conservation, Navier-Stokes equation, internal energy conservation and equation of state of water vapor in the form of a perfect gas. Visualization of calculation results was carried out by the ParaView graphic platform. The features of supersonic high-speed flow regime in a jet accompanied by the formation of a hollow jet in a form close to parabolic are investigated.

Visualization of High Speed Flow in a Pipe with Cavity

1997 ◽  
Vol 17 (Supplement2) ◽  
pp. 113-116
Author(s):  
Kenji HOSOI ◽  
Masaaki KAWAHASHI ◽  
Hiroyuki HIRAHARA ◽  
Kouju SHIOZAKI ◽  
Kenichirou SATOH
Keyword(s):  
High Speed ◽  
High Speed Flow ◽  
Speed Flow

Internal laminar flow

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Poiseuille Flow ◽  
Stokes Equations ◽  
Circular Cross Section ◽  
Navier Stokes ◽  
Parallel Plates ◽  
Concentric Cylinder ◽  
Navier Stokes Equations ◽  
Concentric Cylinders ◽  
Constant Viscosity ◽  
Pressure Driven Flow

In this chapter it is shown that solutions to the Navier-Stokes equations can be derived for steady, fully developed flow of a constant-viscosity Newtonian fluid through a cylindrical duct. Such a flow is known as a Poiseuille flow. For a pipe of circular cross section, the term Hagen-Poiseuille flow is used. Solutions are also derived for shear-driven flow within the annular space between two concentric cylinders or in the space between two parallel plates when there is relative tangential movement between the wetted surfaces, termed Couette flows. The concepts of wetted perimeter and hydraulic diameter are introduced. It is shown how the viscometer equations result from the concentric-cylinder solutions. The pressure-driven flow of generalised Newtonian fluids is also discussed.

Sign in / Sign up

Export Citation Format

Share Document