Three-Dimensional Time-Resolved Inlet Guide Vane-Rotor Potential Field Interaction

2004 ◽  
Vol 20 (1) ◽  
pp. 171-179 ◽  
Author(s):  
Robert T. Johnston ◽  
Sanford Fleeter
Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 172
Author(s):  
Hengtao Shi

Recently, a new type of low-loss variable inlet guide vane (VIGV) was proposed for improving a compressor’s performance under off-design conditions. To provide more information for applications, this work investigated the effect of the Reynolds number and clearance flow on the aerodynamic characteristics of this new type of VIGV. The performance and flow field of two representative airfoils with different chord Reynolds numbers were studied with the widely used commercial software ANSYS CFX after validation was completed. Calculations indicate that, with the decrease in the Reynolds number Rec, the airfoil loss coefficient ω and deviation δ first increase slightly and then entered a high growth rate in a low range of Rec. Afterwards, a detailed boundary-layer analysis was conducted to reveal the flow mechanism for the airfoil performance degradation with a low Reynolds number. For the design point, it is the appearance and extension of the separation region on the rear portion; for the maximum incidence point, it is the increase in the length and height of the separation region on the former portion. The three-dimensional VIGV research confirms the Reynolds number effect on airfoils. Furthermore, the clearance leakage flow forms a strong stream-wise vortex by injection into the mainflow, resulting in a high total-pressure loss and under-turning in the endwall region, which shows the potential benefits of seal treatment.


1984 ◽  
Vol 106 (2) ◽  
pp. 337-345
Author(s):  
B. Lakshminarayana ◽  
N. Sitaram

The annulus wall boundary layer inside the blade passage of the inlet guide vane (IGV) passage of a low-speed axial compressor stage was measured with a miniature five-hole probe. The three-dimensional velocity and pressure fields were measured at various axial and tangential locations. Limiting streamline angles and static pressures were also measured on the casing of the IGV passage. Strong secondary vorticity was developed. The data were analyzed and correlated with the existing velocity profile correlations. The end wall losses were also derived from these data.


Author(s):  
Andrea Arnone ◽  
Roberto Pacciani

A recently developed, time-accurate multigrid viscous solver has been extended to handle quasi-three-dimensional effects and applied to the first stage of a modern transonic compressor. Interest is focused on the inlet guide vane (IGV):rotor interaction where strong sources of unsteadiness are to be expected. Several calculations have been performed to predict the stage operating characteristics. Flow structures at various mass flow rates, from choke to near stall, are presented and discussed. Comparisons between unsteady and steady pitch-averaged results are also included in order to obtain indications about the capabilities of steady, multi-row analyses.


1997 ◽  
Vol 119 (3) ◽  
pp. 539-543 ◽  
Author(s):  
J. Jiang ◽  
T. Dang

This paper presents a procedure to extend a recently developed three-dimensional inverse method for infinitely thin blades to handle blades with finite thickness. In this inverse method, the prescribed quantities are the blade pressure loading and the blade thickness distributions, and the calculated quantity is the blade mean camber line. The method is formulated in the fully inverse mode whereby the blade shape is determined iteratively using the flow-tangency condition along the blade surfaces. Design calculations are presented for an inlet guide vane, an impulse turbine blade, and a compressor blade in the two-dimensional inviscid- and incompressible-flow limit. Consistency checks are carried out for these design calculations using a panel analysis method and the analytical solution for the Gostelow profile.


2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Jens Niewoehner ◽  
Thorsten Poehler ◽  
Peter Jeschke ◽  
Yavuz Guendogdu

This paper is the second part of a two-part paper reporting on the increase in efficiency of a 1.5 stage axial test rig turbine with the use of nonaxisymmetric endwalls and 3D airfoil design. Contoured endwalls were developed for the inlet guide vane separately, as well as in combination with a bowed radial profile stacking. In addition, a contour endwall was applied to the hub of the unshrouded rotor. In Part I, the design of the profiled endwalls and 3D airfoils is presented, as well as a detailed analysis of the steady and unsteady computational fluid dynamics (CFD) results. Part II reports on the experimental validation of the numerical results. A distinct increase in mechanical efficiency for both new configurations in good agreement with the numerical results is observed. Additionally, performance map measurements demonstrate that the new designs are also beneficial under off-design conditions. Five- and three-hole-probes as well as fast-response total pressure probes are used to investigate the new designs. The main effect is the homogenization of the yaw angle behind the first stator.


Author(s):  
Jun Jiang ◽  
Thong Dang

This paper presents a procedure to extend a well-developed fully three-dimensional inverse method for infinitely-thin blades to handle blades with finite thickness. In this inverse method, the prescribed quantities are the blade pressure loading and the blade thickness distributions, and the calculated quantity is the blade geometry. The method is formulated in the fully inverse mode whereby the blade shape is determined iteratively using the flow-tangency condition along the blade surfaces. This technique is demonstrated here in the first instance for the design of cascaded blades in inviscid and incompressible flows. Design calculations are presented for an inlet guide vane, an impulse turbine blade, and a compressor blade. Consistency checks are carried out for these design calculations using a panel analysis method and the analytical solution for the Gostelow profile.


1998 ◽  
Vol 120 (1) ◽  
pp. 147-155 ◽  
Author(s):  
A. Arnone ◽  
R. Pacciani

A recently developed, time-accurate multigrid viscous solver has been extended to handle quasi-three-dimensional effects and applied to the first stage of a modern transonic compressor. Interest is focused on the inlet guide vane (IGV)-rotor interaction where strong sources of unsteadiness are to be expected. Several calculations have been performed to predict the stage operating characteristics. Flow structures at various mass flow rates, from choke to near stall, are presented and discussed. Comparisons between unsteady and steady pitch-averaged results are also included in order to obtain indications about the capabilities of steady, multi-row analyses.


Author(s):  
Angelo Grimaldi ◽  
Libero Tapinassi ◽  
Andrea Bernocchi ◽  
Fernando Roberto Biagi ◽  
Denis Guenard ◽  
...  

Cooling cycle in applications such as Liquefied Natural Gas makes use of centrifugal impellers associated with heavy gas. Increasing projects handled flow leads compressor manufacturers to try to increase flow coefficient and peripheral Mach Number of those stages to limit compressor size. As a consequence, severe aerodynamic problems linked to the blade aspect ratio, meridional channel curvature and inlet tip relative Mach number arise. Of the three, the onset of transonic or supersonic inlet conditions at tip is a matter of concern since it can significantly reduce stage range and performance. Very aggressive blade redesign is often not possible due to mechanical limitations. An accurate coupling of the impeller with the upstream stator parts may partly overcome the problem. The paper summarizes the design activity of a centrifugal stage designed for inlet pre-rotation, covering the most significant considerations made during its design, starting from 1D preliminary design until three dimensional CFD verifications. Finally, the paper draws conclusions on comparison with the results of an experimental campaign the purpose of which was to evaluate the benefits brought about by the new impeller design and different inlet configurations. The new impeller design allowed to reach still acceptable operating range even with relative Mach Number of 1.05 but with a noticeable efficiency decay. Use of Inlet Guide Vane with prewhirl, to bring Mach down to lower value, allowed to recover efficiency values without any further gain of operating range.


Author(s):  
Hideomi Harada

In order to improve the operating range of a centrifugal compressor, computer-controlled variable inlet and diffuser vanes were attached to a compressor with a pressure ratio of 2.5. Low-solidity cascade vanes capable of controlling the vane angle up to 0 degrees from the tangential direction were used for the vaned diffuser. The compressor’s overall performance was then tested using a closed-loop test stand. By automatically adjusting the diffuser vanes to the most suitable flow angle, pressure fluctuations caused by the unstable flow in the diffuser during low-flow operation of the centrifugal compressor could be suppressed, and the compressor could be operated nearly up to the shut-off flow rate without any surge. The author experimentally confirmed the critical operating range of both the impeller and diffuser at two different tip speeds and five inlet guide vane angles. Furthermore, a three-dimensional viscous flow-analysis method was applied to the impeller, and a three-dimensional momentum integral analysis method was applied to the diffuser. Then the critical operating ranges obtained in the experiments were qualitatively validated. The operating range of a centrifugal compressor under low-flow conditions, which has until now been limited because of surge, dramatically improved in this study, thereby demonstrating that it may be possible to develop a surge-free centrifugal compressor.


Author(s):  
L He

Partial admission in the steam turbine is associated with strong unsteady flow effects on aerodynamic performance. This paper presents a first-of-its-kind computational study of the problem. The unsteady flow field in multiple blade passages and multiple blade rows is governed by the quasi three-dimensional unsteady Navier-Stokes equations, closed by a mixing-length turbulence model. The partial admission is introduced by blocking one segmental arc (or several segmental arcs) of the inlet guide vane of the first stage. The flow equations are solved by using a time-dependent finite volume method. The calculated unsteady force on rotor blades for a turbine stage at partial admission compares well with the corresponding experimental data. The present results show that a cyclic pumping and sucking phenomenon occurs in the rotor blade row of the first stage, resulting in large unsteady loading and marked mixing loss. For a single stage at a given admission rate, a blocking arrangement with two flow segments is shown to be much more detrimental than one arc of admission, because of the extra mixing loss. The results for a two-stage case, however, suggest that the decaying rate of circumferential non-uniformities could be far more important for performance. For this reason, an enhanced mixing loss in the first stage might be beneficial to the overall efficiency of a multistage turbine.


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