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.

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.

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.

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.

scholarly journals The Effect of Inlet Swirl on the Rotordynamic Shroud Forces in a Centrifugal Pump

1992 ◽  
Author(s):  
A. Guinzburg ◽  
C. E. Brennen ◽  
A. J. Acosta ◽  
T. K. Caughey
Keyword(s):  
Centrifugal Pump ◽  
Guide Vane ◽  
Tangential Force ◽  
Inlet Guide Vane ◽  
Fluid Forces ◽  
Leakage Flows ◽  
Leakage Path ◽  
Inlet Swirl ◽  
Rotating Impeller ◽  
Rotordynamic Forces

The role played by fluid forces in determining the rotordynamic stability of a centrifugal pump is gaining increasing attention. The present research investigates the contributions to the rotordynamic forces from the discharge-to-suction leakage flows between the front shroud of the rotating impeller and the stationary pump casing. In particular, the dependency of the rotordynamic characteristics of leakage flows on the swirl at the inlet to the leakage path was examined. An inlet guide vane was designed for the experiment so that swirl could be introduced at the leakage flow inlet. The data demonstrates substantial rotordynamic effects and a destabilizing tangential force for small positive whirl ratios; this force decreased with increasing flow rate. The effect of swirl on the rotordynamic forces was found to be destabilizing.

Analysis of oil and gas flow characteristics in the reservoir with the elastic outer boundary

2019 ◽  
Vol 175 ◽  
pp. 280-285 ◽  
Author(s):  
Shunchu Li ◽  
Chaochao Zhao ◽  
Pengshe Zheng ◽  
Qinmin Gui
Keyword(s):  
Gas Flow ◽  
Oil And Gas ◽  
Outer Boundary ◽  
Flow Characteristics

Numerical and Experimental Investigation on the Influence of Blades Gap Flow on Axial Blood Pump Performance

2019 ◽  
Author(s):  
Guangmao Liu ◽  
Donghai Jin ◽  
Mengyu Wang ◽  
Xingmin Gui
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Pressure Rise ◽  
Blood Pump ◽  
Inlet Guide Vane ◽  
Pump Efficiency ◽  
Blade Root ◽  
Gap Flow ◽  
Blade Tip

Abstract The axial blood pump body primarily contains the Inlet Guide Vane (IGV), Rotor Impeller (RI), Outlet Guide Vane (OGV) and pump casing. There must be gaps between rotor blade tip and pump casing or between OGV blade root and rotor hub for the impeller rotating in the pump. The flow characteristics inside an axial blood pump with different blade gaps were numerically simulated and analyzed. Hydraulics experiments were conducted to verify the numerical results. The results show that the pump efficiency decreased slowly when the OGV blade gap increased from 0.1 mm to 0.3 mm, but quickly when the rotor blade gap increased from 0.1 mm to 0.3 mm. The hydraulics characteristic results indicate that the pressure rise and efficiency are mainly influenced by the rotor blade gap. The OGV blade root gaps have little influence on the decrease of pressure rise and efficiency. The novel configuration with uneven blade gaps inside the pump result in improved hydraulics and hemolytic performance compared with the similarly sized configuration with even blade gaps.

An Experimental Study of Controlled Gas-Phase Combustion in Porous Media for Enhanced Recovery of Oil and Gas

2001 ◽  
Author(s):  
Javier E. Sanmiguel ◽  
S. A. (Raj) Mehta ◽  
R. Gordon Moore
Keyword(s):  
Experimental Study ◽  
Porous Media ◽  
Gas Phase ◽  
Oil Recovery ◽  
Gas Flow ◽  
Oil And Gas ◽  
Enhanced Recovery ◽  
Gas Production ◽  
Operating Conditions ◽  
Operating Pressure

Abstract Gas-phase combustion in porous media has many potential applications in the oil and gas industry. Some of these applications are associated with: air injection based improved oil recovery (IOR) processes, formation heat treatment for remediation of near well-bore formation damage, downhole steam generation for heavy oil recovery, in situ preheating of bitumen for improved pumping, increased temperatures in gas condensate reservoirs, and improved gas production from hydrate reservoirs. The available literature on gas-phase flame propagation in porous media is limited to applications at atmospheric pressure and ambient temperature, where the main application is in designing burners for combustion of gaseous fuels having low calorific value. The effect of pressure on gas-phase combustion in porous media is not well understood. Accordingly, this paper will describe an experimental study aimed at establishing fundamental information on the various processes and relevant controlling mechanisms associated with gas-phase combustion in porous media, especially at elevated pressures. A novel apparatus has been designed, constructed and commissioned in order to evaluate the effects of controlling parameters such as operating pressure, gas flow rate, type and size of porous media, and equivalence ratio on combustion characteristics. The results of this study, concerned with lean mixtures of natural gas and air and operational pressures from atmospheric (88.5 kPa or 12.8 psia) to 433.0 kPa (62.8 psia), will be presented. It will be shown that the velocity of the combustion front decreases as the operating pressure of the system increases, and during some test operating conditions, the apparent burning velocities are over 40 times higher than the open flame laminar burning velocities.

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.

Wet Gas Compressor Model Validation

2019 ◽  
Author(s):  
Martin Bakken ◽  
Tor Bjørge ◽  
Lars E. Bakken
Keyword(s):  
Dynamic Model ◽  
Gas Flow ◽  
Petroleum Industry ◽  
Ambient Air ◽  
Open Loop ◽  
Test Facility ◽  
Centrifugal Impeller ◽  
Test Cases ◽  
Liquid Content ◽  
Wet Gas

Abstract The continuous demand for oil and gas forces the petroleum industry to develop new and cost-efficient technologies to increase recovery from new fields and enhance extraction from existing fields. Subsea wet gas compression stands out as a promising solution to increase field extraction, utilize remote regions and reduce costs. Today, a few subsea compressor systems are already operating while several new installations are expected within the next years. This creates a need for dynamic simulation tools to ensure proper system design and facilitate production. This paper presents the model setup for the wet gas compressor test facility at the Norwegian University of Science and Technology (NTNU). The test facility is an open loop configuration consisting of a single shrouded centrifugal impeller, a vaneless diffuser and a circular volute. The fluid is a mixture of ambient air and water. The analysis presented here validates the dynamic model behavior against transient experimental test cases, which include step changes in liquid content and driver trip in both wet and dry conditions. Further, the discharge valve performance has been analyzed in both dry and wet gas flow. The test reveals that the dynamic model is able to operate in a stable manner while showing a close correspondence to the transient test cases. Care should be taken in utilizing dry gas valve characteristics in multiphase flows as increased liquid content has a distinct impact on the valve performance.

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