Flow In Linear Compressor Cascade Research Articles

Detached Eddy Simulation of Transition in Turbomachinery: Linear Compressor Cascade

AbstractThe adaptive, ℓ2–ω delayed detached eddy simulation model was selected to simulate the flow in the V103 linear compressor cascade. The Reynolds number based on axial chord length is 138, 500. Various inflow turbulent intensities from 0% to 10% were tested to evaluate the performance of the adaptive model. The adaptive model is capable of capturing the laminar boundary layer and the large-scale perturbations inside it. The instability of large-scale disturbances signals the switch to a hybrid simulation of the turbulent boundary layer—thus, the transition front is predicted. In the case of separation-induced transition, the adaptive model, which uses eddy simulation in separated flow, can predict the separation bubble size accurately. Generally, the adaptive ℓ2–ω model can simulate the transitional separated flow in a linear compressor cascade, with a correct response to varying turbulent intensities.

Groove型ケーシングトリートメントが圧縮機直線翼列内の翼端漏れ流れの挙動に及ぼす影響 (ミッドコードに設けた単－Grooveの影響)

Groove型ケーシングトリートメントが圧縮機直線翼列内の翼端漏れ流れの挙動に及ぼす影響 (ミッドコードに設けた単－Grooveの影響)

Influence of Incidence Angle on Behavior of Tip Leakage Flow in Linear Compressor Cascade

Influence of Incidence Angle on Behavior of Tip Leakage Flow in Linear Compressor Cascade

Computation of tip-leakage flow in a linear compressor cascade with a second-moment turbulence closure

Strong interaction among tip-leakage vortex, mainstream, passage vortex and turbulence in and behind the blade tip and casing in compressors is one of the major causes of energy losses, affecting the overall gas turbine performance. A number of experiments and recent large-eddy simulations of simplified generic tip-clearance configurations have substantially advanced the understanding of the complex vortical and turbulence structures and energy conversion in and behind a very narrow clearance space. However, the prediction of phenomena in real turbomachinery still relies on the one-point (Reynolds-averaged Navier–Stokes, RANS) Computational Fluid Dynamics which is still burdened by uncertainties related primarily to inadequate turbulence modelling, and also to insufficient accuracy of the numerical algorithms. In this paper we address both these issues by testing an advanced turbulence model and a numerical method in the computations of a tip-clearance flow in a three-dimensional linear compressor cascade. For closing the mean momentum equations we adopted a Second Moment Turbulence Closure (SMC) incorporating low- Re-number and wall proximity effects, which has earlier proved to reproduce accurately a series of generic two- and three-dimensional anisotropic and non-equilibrium flows relevant to turbomachinery. In order to diminish numerical uncertainties, the computations are performed using Petrov-Galerkin stabilized finite element code featuring equal order Q1–Q1 pairs. The solution scheme is based on an in-house parallel Overlapping Domain Decomposition approach featuring a FGMRes linear solver. The results, compared with experiments and the conventional linear low- Re-number eddy viscosity model demonstrate that the SMC here adopted is capable to reproduce all the phenomenological features related to tip-leakage flows, especially the evolution of the strong three-dimensionality and turbulence anisotropy, and can be considered a prospective model for predicting real turbomachinery flows.

Numerical Simulation of Three-Dimensional Viscous Flow in a Linear Compressor Cascade With Tip Clearance

A Navier–Stokes solver is applied to investigate the three-dimensional viscous flow in a low-speed linear compressor cascade with tip clearance at design and off-design conditions with two different meshes. The algebraic turbulence model of Baldwin–Lomax is used for closure. Relative motion between the blades and wall is simulated for one flow coefficient. Comparisons with experimental data, including flow structure, static and total pressures, velocity profiles, secondary flows and vorticity, are presented for the stationary wall case. It is shown that the code predicts well the flow structure observed in experiments and shows the details of the tip leakage flow and the leading edge horseshoe vortex.

Tip Leakage Flow in Linear Compressor Cascade

Tip leakage flow in a linear compressor cascade of NACA 65-1810 profiles is investigated, for tip clearance levels of 1.0, 2.0, and 3.25 percent of chord at design and off-design flow conditions. Velocity and pressure data are collected from three transverse sections inside tip clearance and sixteen sections within flow passage. Tip separation vortex influence is identified from the data. Leakage flow mixing is clearly present inside the clearance and has a significant influence on the internal loss.