The Use of Variable Inlet Guide Vane or Speed Control to Maintain Constant Compressor Pressure Ratio in Wet Gas Flow and Their Effect on Diffuser Stability

2017 ◽  
Author(s):  
Levi André B. Vigdal ◽  
Lars E. Bakken
Keyword(s):  
Gas Flow ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Gas Production ◽  
Inlet Guide Vane ◽  
Two Phase ◽  
Inlet Stream ◽  
Wet Gas ◽  
Compressor Pressure Ratio ◽  
Variable Inlet Guide Vane

Improving offshore gas production requires the process compressor to be moved closer to the wellhead. This will yield such benefits as enhanced well output, longer well life and the possibility of exploiting smaller fields. However, the harsh environment, remote location and variable two-phase characteristics of an untreated gas stream pose increased challenges for operational performance and robustness. Several methods are available to ensure that a process compressor maintains constant outlet pressure regardless of inlet stream properties and flow. Two pressure-ratio control methods — variable inlet guide vanes (IGV) and variable speed — have been investigated. Their effect on diffuser stability has been tested and analysed in dry and wet conditions. Increased diffuser stability in wet conditions with IGV has been discussed and results are presented.

Variable Inlet Guide Vane Losses and Their Effect on Downstream Impeller and Diffuser in Wet Gas Flow

2017 ◽  
Author(s):  
Levi André B. Vigdal ◽  
Lars E. Bakken
Keyword(s):  
Gas Flow ◽  
Oil And Gas ◽  
Guide Vane ◽  
Gas Production ◽  
Test Facility ◽  
Innovative Technology ◽  
Inlet Guide Vane ◽  
Oil And Gas Production ◽  
Wet Gas ◽  
The Impact

Adopting the innovative technology found in a compressor able to compress a mixture of natural gas and condensate has great potential for meeting future challenges in subsea oil and gas production. Benefits include reduced size, complexity and cost, enhanced well output, longer producing life and increased profits, which in turn offer opportunities for exploiting smaller oil and gas discoveries or extending the commercial life of existing fields. Introducing liquid into a centrifugal compressor creates several thermodynamic and fluid-mechanical challenges. The paper reviews some of the drive mechanisms involved in wet gas compression and views them in the context of the test results presented. An inlet guide vane (IGV) assembly has been installed in a test facility for wet gas compressors and the effect of wet gas on IGV performance documented. The impact of changes in IGV performance on impeller and diffuser has also been documented. The results have been discussed and correction methods compared.

Design of the High Pressure Ratio Transonic 1-1/2 Stage Fan Demonstrator Hulda

2007 ◽  
Author(s):  
Hans Ma˚rtensson ◽  
Jo¨rgen Burman ◽  
Ulf Johansson
Keyword(s):  
Guide Vane ◽  
Pressure Ratio ◽  
Inlet Guide Vane ◽  
Demonstration Program ◽  
Good Efficiency ◽  
High Pressure Ratio ◽  
Mechanical Constraints ◽  
Computational Analyses ◽  
Variable Inlet Guide Vane ◽  
First Time

As the first design in a demonstration program for future fighter engine fans a 400 mm 1-1/2 stage fan has been designed and built. A new method including mechanical constraints for designing the blades and gas path is used for the first time on a new design. The approach closely integrates CFD for performance and FE methods for the structure. By this, advanced computational analyses affect the design from the early stages. A design that is successful in achieving good efficiency based on CFD as well as reasonable aeromechanical properties based on FE is derived. The fan incorporates a front frame (FF), variable inlet guide vane (VIGV), rotor 1 (R1) and stator 1 (S1).

Variable Inlet Guide Vane Effect on Centrifugal Compressor Performance in Wet Gas Flow

2016 ◽  
Author(s):  
Levi André B. Vigdal ◽  
Lars E. Bakken
Keyword(s):  
Centrifugal Compressor ◽  
Guide Vane ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Compressor Stage ◽  
Guide Vanes ◽  
Wet Gas ◽  
Compressor Performance

The introduction of variable inlet guide vanes (VIGVs) upfront of a compressor stage affects performance and permits tuning for off-design conditions. This is of great interest for emerging technology related to subsea compression. Unprocessed gas from the wellhead will contain liquid condensate, which affects the operational condition of the compressor. To investigate the effect of guide vanes on volume flow and pressure ratio in a wet gas compressor, VIGVs are implemented upfront of a centrifugal compressor stage to control the inlet flow direction. The guide vane geometry and test rig setup have previous been presented. This paper documents how changing the VIGV setting affects compressor performance under dry and wet operating conditions. The reduced performance effect and operating range at increased liquid content are of specific interest. Also documented is the change in the VIGV effect relative to the setting angle.

An Experimental Study of the Slip Factor in a Wet Gas Centrifugal Compressor With IGV

2017 ◽  
Author(s):  
Levi André B. Vigdal ◽  
Lars E. Bakken
Keyword(s):  
Experimental Study ◽  
Gas Flow ◽  
Oil And Gas ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Inlet Guide Vane ◽  
Liquid Content ◽  
Slip Factor ◽  
Wet Gas ◽  
Inlet Swirl

The introduction of wet gas compression provides the opportunity for future cost-effective production of oil and gas. A wet gas compressor consists of a robust unit able to increase the pressure of untreated natural gas. This permits longer transport of hydrocarbons without topside facilities if installed at the well head. Obvious benefits include prolonging the life of existing wells and the possibility of exploiting smaller hydrocarbon sources otherwise considered non-commercial. Successful development of robust wet gas compressors requires further understanding of the phenomena which occur when liquid is present in the gas stream. Understanding the way the presence of liquid affects the velocity triangle and slip factor is essential for the design of wet gas compressors and for comprehending their response to varying levels of liquid content in the inlet stream. An experimental study has been performed with various levels of liquid fractions and inlet swirl angles. Impeller-exit velocity components and shift in slip factors are presented within the experimental test boundary. A shift in velocity components and slip factor is experienced with increasing liquid content and inlet guide vane (IGV) setting angle. Consequently, existing slip factor correlations not utilizing inlet flow characteristics are not valid for wet gas flow or with impeller inlet swirl.

Inlet Guide Vane Performance at Dry and Wet Gas Conditions

2015 ◽  
Author(s):  
Levi B. Vigdal ◽  
Lars E. Bakken
Keyword(s):  
Gas Flow ◽  
Guide Vane ◽  
Incidence Angle ◽  
Flow Direction ◽  
Volume Flow ◽  
Inlet Guide Vane ◽  
Compressor Stage ◽  
Compressor Wheel ◽  
Wet Gas ◽  
Compressor Impeller

As inlet properties of compressor stage deviates from design point, the compressor stage efficiency will be degraded. A change in properties typically affects the inlet volume flow and inlet Mach number. To maintain optimum performance a static stage called Variable Inlet Guide Vanes (IGV) is implemented before the compressor wheel to manipulate the inlet flow direction. The vanes are of airfoil type geometry, twisted in radial direction to compensate for compressor peripheral speed. The RMS radius has a geometrical flow turning of 20 degrees. Extensive research exists on vane performance in dry gas conditions, but there are however limited results on vane performance shift from dry to wet gas flow. This paper focuses on twisted VIGV performance with GMF down to 80 percent. The VIGV is mounted in front of a centrifugal compressor impeller operating at 9000 rpm. An outlet throttle valve is adjusted to allow for performance at constant gas volume flow. Increased liquid content shows a general reduction in continuity wave size. At low GVF the wave disappeared or was reduced drastically, only to reappear when the incidence angle was increased. This is presumably from the balance of momentum between the pressure side Horse Shoe Vortex and main flow. Flow separation was not observed at any incidence angles or GVF. A vortex at the trailing edge was observed which also allowed the movement of liquid in span-wise direction. Traces of several vortices were observed at all GVF. The general propagation of the vortices fits well with dry gas theory.

scholarly journals Effect of the Reynolds Number and Clearance Flow on the Aerodynamic Characteristics of a New Variable Inlet Guide Vane

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 172
Author(s):  
Hengtao Shi
Keyword(s):  
Reynolds Number ◽  
Guide Vane ◽  
Three Dimensional ◽  
High Growth ◽  
Aerodynamic Characteristics ◽  
Inlet Guide Vane ◽  
Separation Region ◽  
Clearance Flow ◽  
New Type ◽  
Variable Inlet Guide Vane

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.

scholarly journals Gas turbine efficiency and ramp rate improvement through compressed air injection

2020 ◽  
pp. 095765092093208 ◽  
Author(s):  
Kamal Abudu ◽  
Uyioghosa Igie ◽  
Orlando Minervino ◽  
Richard Hamilton
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Injection Rate ◽  
Inlet Guide Vane ◽  
Heavy Duty ◽  
Part Load ◽  
Surge Margin ◽  
Rate Improvement ◽  
Heavy Duty Gas Turbine ◽  
Variable Inlet Guide Vane

With the transition to more use of renewable forms of energy in Europe, grid instability that is linked to the intermittency in power generation is a concern, and thus, the fast response of on-demand power systems like gas turbines has become more important. This study focuses on the injection of compressed air to facilitate the improvement in the ramp-up rate of a heavy-duty gas turbine. The steady-state analysis of compressed airflow injection at part-load and full load indicates power augmentation of up to 25%, without infringing on the surge margin. The surge margin is also seen to be more limiting at part-load with maximum closing of the variable inlet guide vane than at high load with a maximum opening. Nevertheless, the percentage increase in the thermal efficiency of the former is slightly greater for the same amount of airflow injection. Part-load operations above 75% of power show higher thermal efficiencies with airflow injection when compared with other load variation approaches. The quasi-dynamic simulations performed using constant mass flow method show that the heavy-duty gas turbine ramp-up rate can be improved by 10% on average, for every 2% of compressor outlet airflow injected during ramp-up irrespective of the starting load. It also shows that the limitation of the ramp-up rate improvement is dominated by the rear stages and at lower variable inlet guide vane openings. The turbine entry temperature is found to be another restrictive factor at a high injection rate of up to 10%. However, the 2% injection rate is shown to be the safest, also offering considerable performance enhancements. It was also found that the ramp-up rate with air injection from the minimum environmental load to full load amounted to lower total fuel consumption than the design case.

Aerodynamic Investigations of a Variable Inlet Guide Vane With Symmetric Profile

2014 ◽  
Author(s):  
David Händel ◽  
Reinhard Niehuis ◽  
Uwe Rockstroh
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Guide Vane ◽  
Reynolds Numbers ◽  
Boundary Layer Transition ◽  
Inlet Guide Vane ◽  
Experimental Investigations ◽  
Wide Range ◽  
Variable Inlet Guide Vane ◽  
Symmetric Profile

In order to determine the aerodynamic behavior of a Variable Inlet Guide Vane as used in multishaft compressors, extensive experimental investigations with a 2D linear cascade have been conducted. All the experiments were performed at the High-Speed Cascade Wind Tunnel at the Institute of Jet Propulsion. They covered a wide range of Reynolds numbers and stagger angles as they occur in realistic turbomachines. Within this work at first the observed basic flow phenomena (loss development, overturning) will be explained. For the present special case of a symmetric profile and a constant decreasing chord length along the vane height, statements about different spanwise position can be made by investigating different Reynolds numbers. The focus of this paper is on the outflow of the VIGV along the vane height. Results for an open flow separation on the suction side are presented, too. Stall condition can be delayed by boundary layer control. This is done using a wire to trigger an early boundary layer transition. The outcomes of the trip wire measurement are finally discussed. The objective of this work is to evaluate the influence of the stagger angle and Reynolds number on the total pressure losses and the deviation angle. The results of the work presented here, gives a better insight of the efficient use of a VIGV.

scholarly journals Flow Measurements Behind the Inlet Guide Vane of a Centrifugal Compressor

1998 ◽  
Author(s):  
I. Kassens ◽  
M. Rautenberg
Keyword(s):  
Centrifugal Compressor ◽  
Total Pressure ◽  
Guide Vane ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Inlet Guide Vane ◽  
Flow Measurements ◽  
Flow Angle ◽  
Partial Load ◽  
Measurement Location

In a centrifugal compressor adjustable inlet guide vanes (IGV) in front of the impeller are used to regulate the pressure ratio and the mass flow. The stationary measurement of the velocity profile in front of the impeller with different angles of the IGV displays shock losses at the inlet edge of blade of the impeller. In the partial-load region (e.g. partial-load efficiency) the radial distribution of the flow influences considerably the performance of the impeller. The tested compressor consists of an adjustable IGV with straight vanes, a shrouded impeller and a vaneless, parallel diffuser. In the first measurement location, behind the IGV, total pressure, static pressure and flow angle were measured with a 5-hole cylinder probe. In the second measurement location, in front of the impeller, the measurement of the total pressure was carried out with a Kiel probe and the flow angle with a Cobra probe accordingly the static wall pressure was measured. Taking into consideration the fundamental thermodynamical equations it was possible to determine the velocity profiles because of the measured distributions of the flow angle in these two measurement locations. For different angles of the IGV and with various mass flows the distributions of the deflection defect behind the IGV are described. Starting with the measured distributions of the flow in front of the impeller the flow angles at the impeller inlet are calculated and the distributions of the incidence angle at the impeller inlet are figured out.

Wet Gas Flow Metering Based on Differential Pressure and BSS Techniques

2011 ◽  
Vol 383-390 ◽  
pp. 4922-4927
Author(s):  
Peng Xia Xu ◽  
Yan Feng Geng
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Liquid Flow Rate ◽  
Differential Pressure ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Metering ◽  
Wet Gas

Wet gas flow is a typical two-phase flow with low liquid fractions. As differential pressure signal contains rich information of flow parameters in two-phase flow metering, a new method is proposed for wet gas flow metering based on differential pressure (DP) and blind source separation (BSS) techniques. DP signals are from a couple of slotted orifices and the BSS method is based on time-frequency analysis. A good relationship between the liquid flow rate and the characteristic quantity of the separated signal is established, and a differential pressure correlation for slotted orifice is applied to calculate the gas flow rate. The calculation results are good with 90% relative errors less than ±10%. The results also show that BSS is an effective method to extract liquid flow rate from DP signals of wet gas flow, and to analysis different interactions among the total DP readings.

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