Compressible Flow in Inlet Guide Vanes With Mechanical Flaps

2004 ◽  
Author(s):  
M. Boehle ◽  
M. Cagna ◽  
Lutz Itter
Keyword(s):  
Mach Number ◽  
Compressible Flow ◽  
Classical Type ◽  
Cfd Simulations ◽  
Guide Vanes ◽  
Flow Physics ◽  
Inlet Guide Vanes ◽  
Flow Phenomena ◽  
Analytical Estimation ◽  
Stagger Angle

The classical type of inlet guide vanes consists of uncambered or slightly cambered profiles, the stagger angle of which can be varied. A more advantageous possibility of generating an angular momentum in front of the rotor of the first stage contains the application of inlet guide vanes with mechanical flaps. This configuration consists of uncambered profiles with mechanical flaps. In the present paper, flow physics is explained for this configuration and compared with the flow physics for the classical type of inlet guide vanes. The configuration with mechanical flaps is examined numerically for 20 deg. and 32 deg. flap angles. The emphasis lies on the description of the compressible flow phenomena, which become dominant if the Mach number of the incoming flow gets close to the critical Mach number. An analytical estimation for the Mach number at the exit of the guide vanes is introduced and the results are discussed together with the results of the CFD simulations.

Influence of Adjustable Inlet Guide Vanes on the Performance Characteristics of a Shrouded Centrifugal Compressor

2017 ◽  
Author(s):  
Yubao Tian ◽  
Yonghong Tang ◽  
Zhiheng Wang ◽  
Guang Xi
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Air Separation ◽  
Performance Characteristics ◽  
Flow Angle ◽  
Separation Unit ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Lag Effect ◽  
Stagger Angle

A shrouded centrifugal compressor model stage used for 120,000 m3/h oxygen production air separation unit was designed and tested at several IGV stagger angles from −15° to +60° and machine Mach number from 0.97 to 0.5. Present research works aimed to assess the influence of the adjustable IGVs and the IGV modeling on the shrouded centrifugal compressor performance characteristics and inlet flow field and to explore the effect factors of the CFD prediction accuracy and compressor stability at different IGV stagger angles. The measured results show that the model stage with 0° IGV stagger angle yields almost the same stagnation pressure ratio performance as the stage-only model but at a lower peak isentropic efficiency. With an appropriate IGV stagger angle setting ranging from −15° to +30°, the compressor stability could be efficiently enhanced. Numerical studies indicate that a large IGV hub gap may lead to a significant lag effect on the flow angle generated by the inlet guide vanes when increasing the IGV stagger angle.

scholarly journals Variable Flow Turbofan Engine for an HSCT Application

1997 ◽  
Author(s):  
George L. Converse ◽  
Donald K. Dunbar ◽  
Marlen L. Miller ◽  
Paul D. Hoskins ◽  
Scott M. Jones
Keyword(s):  
Mach Number ◽  
Pressure Ratio ◽  
High Flow ◽  
Turbofan Engine ◽  
Variable Flow ◽  
Guide Vanes ◽  
Turbofan Engines ◽  
Inlet Guide Vanes ◽  
Specific Thrust ◽  
Aircraft Propulsion System

A variable flow fan aircraft propulsion system offers the potential for achieving a low specific thrust with high flow and low jet velocity requirement as specified for takeoff, side-line noise, initial climb, and a high specific thrust requirement for climb and acceleration to supersonic cruise. These requirements are conflicting. To achieve this, the operating envelope of a variable flow fan has to be expanded over existing turbofan engines. The variable flow fan concept (i.e., the Variable Fan Exit or “VFX”) can efficiently operate beyond the usual fan (or compressor) stall operating line using novel methods of designing and scheduling the fan geometry as a function of flight Mach Number, fan pressure ratio and corrected speed. Fan geometry is altered by using variable inlet guide vanes (IGV’s), variable stators, and variable outlet guide vanes (OGV’s).

scholarly journals Effects of Inlet Guide Vanes on the Performance and Stability of an Aeronautical Centrifugal Compressor

2020 ◽  
Author(s):  
Nicolas Poujol ◽  
Isabelle Trébinjac ◽  
Pierre Duquesne
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Centrifugal Compressor ◽  
Compressor Stage ◽  
Lower Mass ◽  
Flow Angle ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Surge Line ◽  
Stagger Angle

Abstract A research centrifugal compressor stage designed and built by Safran Helicopter Engines is tested at 3 IGV (Inlet Guide Vanes) stagger angles. The compressor stage includes 4 blade rows: axial inlet guide vanes, a backswept splittered impeller, a splittered vaned radial diffuser and axial outlet guide vanes. The methodology for calculating the performance is detailed, including the consideration of humidity in order to minimize errors related in particular to operating atmospheric conditions. The shift of the surge line towards lower mass flow rate as the IGV stagger angle increases highly depends on the rotation speed. The surge line shift is very small at low rotation speeds whereas it significantly increases at high rotation speeds. A firstorder stability analysis of the impeller and diffuser subcomponents shows that the diffuser (resp. impeller) is the first unstable component at low (resp. high) rotation speeds. This situation is unaltered by increasing the IGV stagger angle. At low rotation speeds below a given mass flow rate, rotating instabilities at the impeller inlet are detected at zero IGV stagger angle. Their occurrence is conditioned by the relative flow angle at the tip of the leading edge of the impeller. As the IGV stagger angle increases, the mass flow decreases to maintain a given inlet flow angle. Therefore, the onset of the rotating instabilities is delayed towards lower mass flow rates. At high rotation speeds, the absolute flow angle at the diffuser inlet near surge decreases as the IGV stagger angle increases. As a result, the flow is highly alternate over two adjacent channels of the radial diffuser beyond the surge line at IGV stagger angle of 0°.

scholarly journals The Influence of Adjustable Inlet Guide Vanes on the Performance of Multi-Stage Industrial Centrifugal Compressors

1992 ◽  
Author(s):  
Klaus Lüdtke
Keyword(s):  
Molecular Weight ◽  
Mach Number ◽  
Power Consumption ◽  
Single Stage ◽  
Centrifugal Compressors ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Multi Stage ◽  
Centrifugal Process ◽  
Influential Parameters

Not only single-stage but also multi-stage centrifugal process compressors are often equipped with one row of adjustable Inlet guide vanes before the first stage. The question, frequently asked by the rotating equipment purchaser is whether such an expensive component is justified for multi-stage centrifugal compressors, since it effects first stage head only. Does or does it not improve turn-down or power consumption in comparison with ordinary butterfly valva suction throttling? The paper examines if and to what degree the favorable turn-down and part-load power consumption of IGV-equipped single-stage machines can be transferred to multi-stage compressors. An intuitive answer of-course is: the lower the number of stages, the more advantageous is the IGV-equipped compressor. There are however other influential parameters like molecular weight of the gas, Mach number, number of intercoolers and others. In contrast to axial and integral gear compressors centrifugal single-shaft compressors cannot be equipped with adjustable IGV’s before each stage due to an extreme lack of interstage space dictated by rotordynamic requirements. The maximum number of IGV’s is two for back-to-back arranged centrifugal impellers.

scholarly journals EFFECTS OF INLET GUIDE VANES ON THE PERFORMANCE AND STABILITY OF AN AERONAUTICAL CENTRIFUGAL COMPRESSOR

2021 ◽  
pp. 1-12
Author(s):  
Nicolas Poujol ◽  
Isabelle Trebinjac ◽  
Pierre Duquesne
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Centrifugal Compressor ◽  
Lower Mass ◽  
Flow Angle ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Surge Line ◽  
Stagger Angle

Abstract A research centrifugal compressor stage designed and built by Safran Helicopter Engines is tested at 3 IGV (Inlet Guide Vanes) stagger angles. The methodology for calculating the performance is detailed, including the consideration of humidity in order to minimize errors related in particular to operating atmospheric conditions. The shift of the surge line towards lower mass flow rate as the IGV stagger angle increases highly depends on the rotation speed. The surge line shift is very small at low rotation speeds whereas it significantly increases at high rotation speeds. A first-order stability analysis of the impeller and diffuser sub-components shows that the diffuser (resp. impeller) is the first unstable component at low (resp. high) rotation speeds. This situation is unaltered by increasing the IGV stagger angle. At low rotation speeds below a given mass flow rate, rotating instabilities at the impeller inlet are detected at zero IGV stagger angle. Their occurrence is conditioned by the relative flow angle at the tip of the leading edge of the impeller. As the IGV stagger angle increases, the mass flow decreases to maintain a given inlet flow angle. Therefore, the onset of the rotating instabilities is delayed towards lower mass flow rates. At high rotation speeds, the absolute flow angle at the diffuser inlet near surge decreases as the IGV stagger angle increases. As a result, the flow is highly alternate over two adjacent channels of the radial diffuser beyond the surge line at IGV stagger angle of 0°.

scholarly journals Influence of grid distribution on CFD model of compressible flow inside the primary nozzle and mixing chamber used in refrigeration application

2018 ◽  
Vol 192 ◽  
pp. 02045
Author(s):  
Natthawut Ruangtrakoon ◽  
Eakarach Bumrungthaichaichan
Keyword(s):  
Experimental Data ◽  
Mach Number ◽  
Numerical Methods ◽  
Compressible Flow ◽  
Total Pressure ◽  
Cfd Model ◽  
Regular Grid ◽  
Mixing Chamber ◽  
Flow Phenomena ◽  
Near Wall

In this study, the influence of grid distribution on CFD model of the primary nozzle and mixing chamber used in refrigeration application was primarily investigated. The only one geometry of primary nozzle and mixing chamber was modeled. The two different grid distributions, fine near-wall grid and regular grid with the identical total grid number, were simulated to investigate the flow phenomena inside the considered system. The appropriate boundary conditions and numerical methods were carefully employed. The simulated entrainment ratios obtained by two different grid arrangements were validated by comparing with the reliable experimental data. The results revealed that the Mach number distributions of these models were different. Further, the outlet total pressure predicted by fine near-wall grid was about 1.3% higher than that obtained by regular grid.

Investigation of Electrohydraulic Control of A Gas Turbine Engine’s Inlet Guide Vanes

2017 ◽  
Vol 17 (17) ◽  
pp. 1-10
Author(s):  
Mostafa Samy ◽  
Mohamed Metwally ◽  
Wael Elmayyah ◽  
Ibrahem Elsherif
Keyword(s):  
Gas Turbine ◽  
Guide Vanes ◽  
Inlet Guide Vanes
Sign in / Sign up

Export Citation Format

Share Document