The Effect of Inlet Conditions on the Performance of Wells Turbine

1989 ◽  
Vol 111 (1) ◽  
pp. 37-42 ◽  
Author(s):  
S. Raghunathan ◽  
T. Setoguchi ◽  
K. Kaneko
Keyword(s):  
Primary Effect ◽  
Experimental Investigations ◽  
Wells Turbine ◽  
Flow Distortion ◽  
Inlet Conditions ◽  
The Postponement

Experimental investigations on the effect of inlet turbulence and flow distortion on the performance of a monoplane and a biplane Wells turbine are reported. The performance of biplane Wells turbine is more sensitive to turbulence when compared with a monoplane. The primary effect of increase in turbulence on the performance of Wells turbine is the postponement of stall.

Void Fraction Physics Resulting From Chaos Control of Upward Gas-Liquid Slug Flow

2001 ◽  
Author(s):  
Robert M. MacMeccan ◽  
Heather M. Langford ◽  
Donald E. Beasley
Keyword(s):  
Slug Flow ◽  
Complex Dynamics ◽  
Open Loop ◽  
Experimental Investigations ◽  
Open Loop Control ◽  
Liquid Slug ◽  
Loop Control ◽  
Air Inlet ◽  
Specific Frequency ◽  
Inlet Conditions

Abstract The present investigation examines open-loop control of chaotic upward gas-liquid slug flow. Though highly structured, slug flow is deterministically chaotic in nature. Recent analytical and experimental investigations indicate that perturbation of a system parameter has the potential to reduce or increase chaos in a system. Slug flow provides an interesting medium for the investigation into control of chaotic systems due to its high degree of structure and complex physics. The response of slug flow under control in turn lends insight into its complex dynamics. The results of the present study validate open-loop control, showing that periodic perturbation of the air inlet conditions at a specific frequency destabilizes dominant system dynamics, pushing the system to less stable orbits with different flow physics.

Experimental Investigations and Numerical Validation of an Outlet Guide Vane With an Engine Mount Recess

2008 ◽  
Author(s):  
Johan Hja¨rne ◽  
Valery Chernoray ◽  
Jonas Larsson
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Guide Vane ◽  
Test Facility ◽  
Experimental Investigations ◽  
Flow Angle ◽  
Sst Model ◽  
Engine Mount ◽  
Inlet Conditions ◽  
Secondary Flow Field

This paper presents experiments and CFD calculations of a Low Pressure Turbine/Outlet Guide Vane (LPT/OGV) equipped with an engine mount recess (a bump) tested in the Chalmers linear LPT/OGV cascade. The investigated characteristics include performance for the design point in terms of total pressure loss and turning as well as a detailed description of the downstream development of the secondary flow field. The numerical simulations are performed for the same inlet conditions as in the test-facility with engine-like properties in terms of Reynolds number, boundary-layer thickness and inlet flow angle. The objective is to validate how accurately and reliably the secondary flow field and losses can be predicted for an LPT/OGV equipped with a bump. Three different turbulent models as implemented in FLUENT, the k-ε realizable model, the kω-SST model and the RSM are validated against detailed measurements. From these results it can be concluded that the kω-SST model predicts both the secondary flow field and the losses most accurately.

Effects of Flow Distortions as They Occur in S-Duct Inlets on the Performance and Stability of a Jet Engine

2015 ◽  
Author(s):  
Rudolf. P. M. Rademakers ◽  
Stefan Bindl ◽  
Reinhard Niehuis
Keyword(s):  
Mesh Size ◽  
Experimental Investigations ◽  
Test Bed ◽  
Flow Distortion ◽  
Jet Engine ◽  
Jet Propulsion ◽  
Inlet Distortion ◽  
Flow Phenomena ◽  
The Impact ◽  
Duct Design

One of the research areas at the Institute of Jet Propulsion focuses on the design and optimization of s-shaped engine inlet configurations. The distortion being evoked within such inlet ducts should be limited to ensure an optimal performance, stability, and durability of the engine’s compression system. Computational Fluid Dynamics (CFD) play a major role in the design process of bent engine inlet ducts. The flow within such ducts can be computed, distortion patterns can be visualized, and related distortion coefficients are easily calculated. The impact of a distortion on flow phenomena within the compressor system can, however, only be computed with major computational efforts and thus the quality of an s-duct design in development is usually assessed by analyzing the evoked distortion with suitable distortion coefficients without a true knowledge of the duct’s influence on the downstream propulsion system. The influence of inlet distortion on both the performance and stability of the Larzac 04 jet engine was parameterized during experimental investigations at the engine test bed of the Institute of Jet Propulsion. Both pressure and swirl distortion patterns as they typically occur in s-duct inlet configurations were reproduced with distortion generators. Pressure distortion patterns were generated using seven types of distortion screens. The intensity of the distortion varies with the mesh size of the screen whereas the extension of the distortion is defined by the dimensions of the screen in radial and circumferential direction. A typical counter rotating twin-swirl was generated with a deltawing installed upstream of the compressor system. First, the development of flow distortion was analyzed for several engine operating points (EOPs). A linear relation between the total pressure loss in the engine inlet and the EOPs was found. Secondly, the flow within the compressor system with an inlet distortion was analyzed and unsteady flow phenomena were detected for severe inlet distortions. Finally, the effect of both pressure and swirl distortion on the performance and stability of the test vehicle was parameterized. A loss in engine performance with increasing inlet distortion is observable. The limiting inlet distortion with respect to engine stability was found and moreover it was shown that pressure distortion has a stronger influence on the stability of the compressor system compared to a counter rotating twin-swirl distortion. The presented parameterization is essential for the s-duct design, which is under development for an experimental set-up with the Larzac 04 jet engine.

Efficiency Improvement and Noise Reduction Through Stator-Stator Clocking Effect of a Two-Stage Turbine

2005 ◽  
Author(s):  
Jaroslaw R. Blaszczak
Keyword(s):  
Acoustic Noise ◽  
Experimental Investigations ◽  
Two Stage ◽  
Machine Vibration ◽  
Low Pressure Turbine ◽  
Measurement Results ◽  
Stator Vane ◽  
Flow Phenomena ◽  
Inlet Conditions ◽  
Good Agreement

The objective of the presented test program was to further experimentally investigate vane-indexing effect influence on the performance, noise and vibration of two-stage low-pressure turbine. Keeping the inlet conditions strictly constant during the tests, two turbine stages were experimentally investigated. Herein, some flow measurement results and the external characteristics for different circumferential positions of the stator vanes are described. Comparisons were made with numerical simulation and they showed good agreement. Experimental data and numerical simulations of stator vane surface pressures are presented to determine how the flow phenomena were affected by indexing of the airfoils for two cases: for nominal rotational speed and for off-design turbine conditions. In addition, correlation to acoustic noise and machine vibration level is presented. They have been found to be clocking dependent. The experimental investigations have been carried out on a two-stage turbine research facility at the Institute of Turbomachinery of the Technical University of Lodz, Poland.

Effect of Inlet Flow Distortion on Performance of Vortex Controlled Diffusers

1992 ◽  
Vol 114 (2) ◽  
pp. 191-197 ◽  
Author(s):  
R. K. Sullerey ◽  
V. Ashok ◽  
K. V. Shantharam
Keyword(s):  
Reynolds Number ◽  
High Pressure ◽  
Velocity Profiles ◽  
Short Length ◽  
Experimental Investigations ◽  
Two Dimensional ◽  
Flow Distortion ◽  
Exit Velocity ◽  
Inlet Velocity ◽  
Vortex Control

The present experimental investigations are concerned with diffusers employing the concept of vortex control to achieve high pressure recovery in a short length. Two types of two-dimensional diffusers have been studied, namely, vortex controlled and hybrid diffusers. Investigations have been carried out on such short diffusers with symmetrically and asymmetrically distorted inlet velocity profiles for area ratios 2.0 and 2.5 and divergence angle of 30 and 45 deg at a Reynolds number of 105. For each of the above configurations, experiments have been carried out for a range of fence subtended angles and bleed rates. The results indicate improvement in diffuser effectiveness up to a particular bleed off for both types of diffusers. It was observed that the nature of exit velocity profiles could be controlled by differential bleed.

scholarly journals Simulating the Effect of Wind on the Performance of Axial Flow Fans in Air-Cooled Steam Condenser Systems

2015 ◽  
Vol 7 (2) ◽  
Author(s):  
Neil Fourie ◽  
S. J. van der Spuy ◽  
T. W. von Backström
Keyword(s):  
Wind Velocity ◽  
Symmetry Plane ◽  
Axial Flow ◽  
Power Industry ◽  
Experimental Investigations ◽  
Flow Conditions ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Wind Velocities ◽  
Inlet Flow Distortion

The use of air-cooled steam condensers (ACSCs) is preferred in the chemical and power industry due to their ability to adhere to stringent environmental and water use regulations. ACSC performance is, however, highly dependent on the prevailing wind conditions. Research has shown that the presence of wind reduces the performance of ACSCs. It has been found that cross-winds (wind perpendicular to the longest side of the ACSC) cause distorted inlet flow conditions, particularly at the upstream peripheral fans near the symmetry plane of the ACSC. These fans are subjected to what is referred to as “two-dimensional” wind conditions, which are characterized by flow separation on the upstream edge of the fan inlets. Experimental investigations into inlet flow distortion have simulated these conditions by varying the fan platform height. Low platform heights resulted in higher levels of inlet flow distortion, as also found to exist with high cross-wind velocities. The similarity between platform height and cross-wind velocity is investigated in this study by conducting experimental and numerical investigations into the effect of distorted inlet flow conditions on the performance of various fan configurations (representative of configurations used in the South-African power industry). A correlation between system volumetric effectiveness, platform height, and cross-wind velocity is derived which provides a means to compare platform height and cross-wind velocity effects.

Influence of Inlet Velocity Ratio on the Outlet Flow Uniformity of a Fan-Shaped Film Cooling Hole

2009 ◽  
Author(s):  
James S. Porter ◽  
Alan D. Henderson ◽  
Gregory J. Walker
Keyword(s):  
Film Cooling ◽  
Large Scale ◽  
Velocity Ratio ◽  
Internal Flow ◽  
Experimental Investigations ◽  
Low Velocity ◽  
Inlet Velocity ◽  
Cooling Hole ◽  
Outlet Flow ◽  
Inlet Conditions

Literature regarding the influence of inlet conditions on cooling hole flows is reviewed. A general failure to fully quantify inlet conditions and an inconsistent terminology for describing them is noted. This paper argues for use of an inlet velocity ratio (IVR) defined as the ratio of the coolant passage velocity to the jet velocity, together with additional parameters required to define the velocity distribution in the coolant supply passage. Large scale experimental investigations of the internal flow field for a laterally expanded 50 times scale fan-shaped hole are presented, together with a computational investigation of the flow, for three inlet velocity ratios. Inlet lip separation causes a jetting effect that extends throughout the length of the cooling hole. A low velocity region of separated fluid exists on the downstream wall of the diffuser which deflects the jetting fluid towards the upstream side of the hole. This effect is most pronounced at low IVR values. The exit velocity profiles and turbulence distributions are highly dependent on the IVR.

scholarly journals Response of a Turbofan Engine Compression System to Disturbed Inlet Conditions

1996 ◽  
Author(s):  
Adnan M. Abdel-Fattah
Keyword(s):  
Inlet Temperature ◽  
Nasa Lewis Research ◽  
Flow Distortion ◽  
Temperature Ramps ◽  
Inlet Conditions ◽  
Flow Effects ◽  
The Stability ◽  
Full Face ◽  
Real Flow ◽  
Pressure Compressor

A generic code DYNTECC has been adapted to perform a parametric study of the effect of inlet flow distortion on the stability of the Pratt and Whitney TF30 engine. This code was developed at Arnold Engineering Development Center, USA, for single and dual spool systems. It was modified at AMRL to accommodate the particular geometry of the TF30 engine. The stage characteristics needed to operate DYNTECC were derived from experimental data for the fan and low pressure compressor. For the high pressure compressor they were derived using the STGSTK code developed at NASA Lewis Research Center. This program was modified at AMRL to include real flow effects that were in turn derived using yet another adapted code CASCAD. The code was primarily used at AMRL to predict the onset of system instability due to simulated full-face rapid inlet temperature ramps typical of those caused during armament firings. It was also run with sinusoidal total pressure oscillations of varying amplitudes and frequencies at the inlet. The code predictions were compared with available data whenever possible, and were found to be consistent with the observed experimental trends.

scholarly journals Experimental Investigations of the Influence of Incoming Wakes on the Losses of a Linear Turbine Cascade

1993 ◽  
Author(s):  
M. Ladwig ◽  
L. Fottner
Keyword(s):  
Suction Side ◽  
Reynolds Numbers ◽  
Experimental Investigations ◽  
Turbine Cascade ◽  
Flow Conditions ◽  
Inlet Flow ◽  
Low Reynolds Numbers ◽  
Blade Passage ◽  
Inlet Conditions ◽  
Hot Film

The objective of this work is to enhance the understanding of the influence of wake induced non-uniform, steady inlet flow conditions on the profile losses of highly-loaded turbines. For different Reynolds numbers wake and profile pressure distribution measurements were carried out on a linear subsonic turbine cascade as well as measurements with a single sensor hot-film probe. The non-uniform inlet flow were simulated with two different cascades of cylindrical bars. The measurements with various circumferential positions of the incoming wakes relative to the turbine cascade show at low Reynolds numbers a decrease of the losses compared to uniform inlet conditions, because no separation of the suction side boundary layer occurs. With increasing Reynolds numbers the non-uniform inlet flow conditions cause an increase in the losses compared to uniform inlet conditions, due to the forward shift of transition. Generally, the smallest influence of the non-uniform incoming flow can be observed when the wakes enter the cascade inlet plane between the pressure-side of the profiles and the middle of the blade passage. Incoming wakes have the highest influence when they enter the blade passage near to the suction side of the profiles.

Effect of Casing Treatment on Performance of a Three-Stage L.P. Compressor

1981 ◽  
Author(s):  
Zhao Quan-chun ◽  
Li Ke-ming ◽  
Sun Yuan-ying
Keyword(s):  
Test Data ◽  
Air Flow ◽  
Constant Speed ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Casing Treatment ◽  
Inlet Distortion ◽  
Surge Margin ◽  
Inlet Conditions ◽  
Design Speed

The test data of a three-stage L.P. compressor with a solid casing and a treated casing under both uniform and circumferentially distorted inlet conditions are presented in this paper. The effects of two different casings on the air flow, efficiency, constant speed line and surge margin of the L.P. compressor are analyzed. Four different configurations of the treated casing were designed and tested. It was found that the surge margin was improved by means of casing treatment. The best one of all configurations is that with large stagnation cell with blades, which brought about increase by 4 percent of the surge margin of the compressor at design speed. The attenuation of inlet flow distortion is also presented with two types of casings. The treated casing has a greater capability to attenuate the inlet distortion than the solid casing.

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