Introduction of Circumferentially Nonuniform Variable Guide Vanes in the Inlet Plenum of a Centrifugal Compressor for Minimum Losses and Flow Distortion

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Ismail Sezal ◽  
Nan Chen ◽  
Christian Aalburg ◽  
Rajesh Kumar V. Gadamsetty ◽  
Wolfgang Erhard ◽  
...  

In the oil and gas industry, large variations in flow rates are often encountered, which require compression trains with a wide operating range. If the stable operating range at constant speed is insufficient, variable speed drivers can be used to meet the requirements. Alternatively, variable inlet guide vanes (IGVs) can be introduced into the inlet plenum to provide pre- or counterswirl to the first-stage impeller, possibly eliminating the need for variable speed. This paper presents the development and validation of circumferentially nonuniform IGVs that were specifically designed to provide maximum angle variation at minimum losses and flow distortion for the downstream impeller. This includes the comparison of three concepts: a baseline design based on circumferentially uniform and symmetric profiles, two circumferentially nonuniform concepts based on uniquely cambered airfoils at each circumferential position, and a multi-airfoil configuration consisting of a uniquely cambered fixed part and a movable part. The idea behind the circumferentially nonuniform designs was to take into account nonsymmetric flow features inside the plenum and a bias toward large preswirl angles rather than counter-swirl during practical operation. The designs were carried out by computational fluid dynamics (CFD) and first tested in a steady, full-annulus cascade in order to quantify pressure losses and flow quality at the inlet to the impeller at different IGV setting angles (ranging from −20 deg to +60 deg) and flow rates. Subsequently, the designs were mounted in front of a typical oil and gas impeller on a high-speed rotating rig in order to determine the impact of flow distortion on the impeller performance. The results show that pressure losses in the inlet plenum could be reduced by up to 40% with the circumferentially nonuniform designs over the symmetric baseline configuration. Furthermore, a significant reduction in circumferential distortion could be achieved with the circumferentially nonuniform designs. The resulting improvement in impeller performance contributed approximately 40% to the overall efficiency gains for inlet plenum and impeller combined.

Author(s):  
Ismail Sezal ◽  
Matthias Lang ◽  
Christian Aalburg ◽  
Nan Chen ◽  
Wolfgang Erhard ◽  
...  

In the Oil & Gas industry, large variations in flow rates are often encountered which require compression trains with a wide operating range. If the stable operating range at constant speed is insufficient, variable speed drivers can be used to meet the requirements. Alternatively, variable guide vanes (IGVs) can be introduced into the inlet plenum to provide pre- or counter-swirl to the first stage impeller, possibly eliminating the need for variable speed. This paper presents the development and validation of circumferentially non-uniform IGVs that were specifically designed to provide maximum angle variation at minimum losses and flow distortion for the downstream impeller. This includes the comparison of three concepts: a baseline design based on circumferentially uniform and symmetric profiles and two circumferentially non-uniform concepts based on uniquely cambered airfoils at each circumferential position and a multi airfoil configuration consisting of a uniquely cambered fixed part and a movable part. The idea behind the circumferentially non-uniform designs was to take into account non-symmetric flow features inside the plenum and a bias towards large preswirl angles rather than counter-swirl during practical operation. The designs were carried out by CFD and first tested in a steady, full-annulus cascade in order to quantify pressure losses and flow quality at the inlet to the impeller at different IGV setting angles (ranging from −20° to +60°) and flow rates. Subsequently, the designs were mounted in front of a typical Oil & Gas impeller on a high speed rotating rig in order to determine the impact of flow distortion on the impeller performance. The results show that pressure losses in the inlet plenum could be reduced by up to 40% with the circumferentially non-uniform designs over the symmetric baseline configuration. Furthermore, a significant reduction in circumferential distortion could be achieved with the circumferentially non-uniform designs. The resulting improvement in impeller performance contributed approx. 40% to the overall efficiency gains for inlet plenum and impeller combined.


Author(s):  
Suheab Thamizullah ◽  
Abdul Nassar ◽  
Antonio Davis ◽  
Gaurav Giri ◽  
Leonid Moroz

Abstract Turbochargers are commonly used in automotive engines to increase the internal combustion engine performance during off-design operating conditions. When used, the widest operating range for the turbocharger is desired, which is limited on the compressor side by the choke condition and the surge phenomenon. The ported shroud technology is used to extend the operable working range of the compressor, by permitting flow disturbances that block the blade passage to escape and stream back through the shroud cavity to the compressor inlet. The impact of this technology, on a speed-line, at near optimal operating condition, near choke operating condition and near surge operating condition is investigated. The ported shroud (PS) self-recirculating casing treatment is widely used to delay the onset of surge by enhancing the aerodynamic stability of the turbocharger compressor. While the ported shroud design delays surge, it usually comes with a small penalty in efficiency. This research involves designing a single-stage centrifugal compressor for the given specifications, considering the application of an automotive turbocharger. The ported shroud was then introduced in the centrifugal compressor. The performance characteristics were obtained, both at the design and at off-design conditions, both with and without the ported shroud. The performance was compared at various off-design operating speed lines. The entire study, from designing the compressor to optimizing the ported shroud configuration, was performed using the commercial AxSTREAM® software platform. Parametric studies were performed to study the effect of ported shroud axial location along the blade axial length on the operating range and performance. The baseline design, without the ported shroud (P0), and the final geometry with it for all PS inlet axial locations (P1 to P5) were analysed using a commercial CFD package and the results were compared with those from the streamline solver.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3537
Author(s):  
Charles Stuart ◽  
Stephen Spence ◽  
Sönke Teichel ◽  
Andre Starke

The implementation of increasingly stringent emissions and efficiency targets has seen engine downsizing and other complementary technologies increase in prevalence throughout the automotive sector. In order to facilitate ongoing improvements associated with the use of these strategies, delivering enhancements to the performance and stability of the turbocharger compressor when operating at low mass flow rates is of paramount importance. In spite of this, a few concepts (either active or passive) targeting such aims have successfully transitioned into use in automotive turbochargers, due primarily to the requirement for a very wide compressor-operating range. In order to overcome the operational limitations associated with existing pre-swirl generation devices such as inlet guide vanes, this study developed a concept comprising of an electrically driven axial fan mounted upstream of a standard automotive turbocharger centrifugal compressor. Rather than targeting a direct contribution to compressor boost pressure, the fan was designed to act as a variable pre-swirl generation device capable of being operated completely independently of the centrifugal impeller. It was envisioned that this architecture would allow efficient generation of the large pre-swirl angles needed for compressor surge margin extension and efficiency enhancement at low mass flow rate-operating points, while also facilitating the delivery of zero pre-swirl at higher mass flow rates to ensure no detrimental impact on performance at the rated power point of the engine. Having progressed through 1-D and 3-D aerodynamic modelling phases to understand the potential of the system, detailed component design and hardware manufacture were completed to enable an extensive experimental test campaign to be conducted. The experimental results were scrutinized to validate the numerical findings and to test the surge margin extension potential of the device. Compressor efficiency improvements of up to 3.0% pts were witnessed at the target-operating conditions.


2010 ◽  
Vol 89 (2) ◽  
pp. 91-107 ◽  
Author(s):  
R. Herber ◽  
J. de Jager

AbstractThe impact of oil and, in particular, gas fields discovered in the Dutch subsurface has been very significant. However, 50 years after the discovery of the giant Groningen gas field the Netherlands has become very mature for exploration of oil and gas, and the gas volume left to be discovered in conventional traps is insignificant compared to what has been found already. The total portfolio of conventional prospects held by the industry contains several 100s of billions of cubic metres (bcm), as reported by the Ministry of Economic Affairs, but many of these prospects are unattractive to drill because of their small size or other geologically unfavourable aspects. Hence, for planning purposes of future national gas production the risk should be taken into account that the size of the conventional portfolio is overestimated. The major E&P companies have reduced their exploration efforts and the number of wells drilled as well as the size and total volume of discovered gas reserves has seen a steady decline over the last 10 years. Some surprises may still be in store and can occasionally add a welcome addition of gas. But the follow-up potential of new play and trapping concepts has been disappointing for many years now, and it is concluded that this is unlikely to be different in the future. Remaining conventional discoveries will mainly be in small near-field targets that as a result of technological advances made in the last few decades can be drilled with high confidence, despite their small volumes.This leaves the so-called unconventional gas (UG) resources for a real and significant increase in the exploration potential of the Netherlands. UG resources occur outside conventional structural or stratigraphic traps in tight (low permeability) rocks and are of regional or sub-regional extent, without well-defined hydrocarbon-water contacts. The potential for Basin Centred Gas, Shale Gas and Coal Bed Methane is reviewed. As, according to present-day technology, development of UG requires very dense drilling at low costs with well spacing of a few 100s of metres, only the onshore potential can be commercial, even in the longer term.Recent geological uplift is a characteristic for all North American commercial UG developments. Uplift helps bringing the resources close to the surface and facilitates development of fractures, which are essential for achieving commercial flow rates. This significantly reduces the area where commercial UG resources may occur in the Netherlands. In addition, sweet spots, where commercial flow rates and ultimate recovery per well can be achieved, represent only a fraction of the total ‘play area’. The UG plays in the Dutch subsurface remain to be proven, and there is still a significant technical risk associated with these plays, on top of the commercial risk. Therefore, despite potentially enormous in-place gas volumes in these unconventional plays, recoverable volumes are much less. If UG resources can be proven and are commercially developable, their cumulative volume potential is estimated by us in the order of a few tens to one or two hundreds bcm of recoverable gas at best. Finally, as UG resources produce at very low rates and require large numbers of wells to develop, the environmental impact in a densely populated country like the Netherlands is enormous, and needs to be seriously considered, already in the exploration phase.In a mature area like the Netherlands, industry focus should be on technology development to reduce risk, increase recovery, reduce cost and minimize surface impact. Cooperation between Operators to build multi-well campaigns is therefore strongly recommended to reduce mobilisation cost. In addition, government incentives should be targeted at the development phase, in order to increase economic attractiveness for difficult reservoirs, both conventional and unconventional. In this way State and industry will both be able to maximize their returns on the remaining potential for gas and oil in the next two to three decades.


Author(s):  
Bruce Bouldin ◽  
Kiran Vunnam ◽  
Jose-Angel Hernanz-Manrique ◽  
Laura Ambit-Marin

Auxiliary Power Units (APU’s) are gas turbine engines which are located in the tail of most commercial and business aircraft. They are designed to provide electrical and pneumatic power to the aircraft on the ground while the main propulsion engines are turned off. They can also be operated in flight, when there is a desire to reduce the load on the propulsion engines, such as during an engine-out situation. Given an APU’s typical position in the back of an airplane, the intake systems for APU’s can be very complex. They are designed to provide sufficient airflow to both the APU and the cooling system while minimizing the pressure losses and the flow distortion. These systems must perform efficiently during static operation on the ground and during flight at very high altitudes and flight speeds. An APU intake system has been designed for a new commercial aircraft. This intake system was designed using the latest Computational Fluid Dynamics (CFD) techniques. Several iterations were performed between the APU supplier and the aircraft manufacturer since each of their components affects the performance of the other. For example, the aircraft boundary layer impacts APU intake performance and an open APU flap impacts aircraft drag. To validate the effectiveness of the CFD analysis, a full scale intake rig was designed and built to simulate the tailcone of the aircraft on the ground. This rig was very large and very detailed. It included a portion of the tailcone and rudder, plus the entire APU and cooling intake systems. The hardware was manufactured out of fiberglass shells, stereolithogrophy components and machined plastic parts. Three different airflows for the load compressor, engine compressor and cooling system had to be measured and throttled. Fixed instrumentation rakes were located to measure intake induced pressure losses and distortion at the APU plenum and cooling ducts. Rotating pressure and swirl survey rakes were located at the load compressor and engine compressor eyes to measure plenum pressure losses and distortion. Static pressure taps measured the flow pattern along the intake and flap surfaces. The intake rig was designed to be flexible so that the impact of rudder position, intake flap position, APU plenum baffle position and compressor airflow levels could be evaluated. This paper describes in detail the different components of the intake rig and discusses the complexity of conducting a rig test on such a large scale. It also presents the impact of the different component positions on intake performance. These results were compared to CFD predicted values and were used to calibrate our CFD techniques. The effectiveness of using CFD for APU intake design and its limitations are also discussed.


2021 ◽  
Author(s):  
Sergey Petrovich Mikhaylov ◽  
Anastasia Andreevna Shtyrlyaeva

Abstract Oil reservoirs are often affected by tectonic processes throughout their lifetime. Tectonic processes contribute to the impact on the formation of a number of mechanical and chemical factors. These factors change the composition and structure of the reservoir and this affects the reservoir properties of the reservoir. Deep-seated reservoirs experience a longer and more intense impact of tectonic processes. A more detailed study of the composition and properties of reservoirs for an accurate forecast of reservoir properties and their productivity potential is due to this. Standard log interpretation methods have been developed based on shallow strata. These methods do not allow taking into account secondary changes in the reservoir and make the calculations of the starting flow rates of wells reliable. J1 stratum West Wing on Nizhnevartovsky set is a prime example of this.


Author(s):  
Stephen D. Hiner

An optimised inlet air system design is an important factor in the gas turbine (GT) industry. Optimising the design of the air intake system is an increasingly challenging process as both the layout complexity and range of features that can be included in the intake system expands. These may include a combination of insect or trash screens, weather protection and filtration systems, silencers, anti-icing systems, ventilation system off takes and inlet heating or cooling systems for power augmentation. Poor designs can result in inefficient use of these components as well as losses in engine performance due to excessive pressure losses or distortion in the flow entering the gas turbine. High flow distortion, velocity, pressure or temperature, can induce compressor surge and high acromechanical stresses in compressor blades and vanes. In extreme cases this may result in blade or vane failures. Computational Fluid Dynamics (CFD) analysis is a powerful tool for visualisation of the predicted flow through a hypothetical air inlet system prior to manufacture. The CFD output plots include flow streamlines and contours, of pressure, velocity or temperature, at any plane in the model. These enable pressure losses, flow distortion issues, potential recirculation areas and high local velocities within the system to be reviewed. This allows optimisation of the installation design to minimise system pressure loss and flow distortion, both through the components and at the engine interface. This paper, with reference to case studies of gas turbine applications, highlights the impact that CFD analysis can have on the design of intake systems to ensure that the best overall performance is obtained. The process of developing the CFD geometry and how significant features of an installation are modeled is outlined. Environmental and operational conditions, such as cross winds can impact the flow through an intake system; therefore, incorporation of such factors into the model boundary conditions are covered. Typical output metrics from the CFD analysis are shown from selected case studies; total pressure drop and flow distortion at the interface plane between the intake system and gas turbine. The importance of experienced interpretation of the CFD output to define potential intake design modifications to improve system performance is highlighted. In specific cases model testing has been carried out to validate CFD results. Case study examples are used to show the improvements made in air intake performance that contribute to increased operational efficiency of the gas turbine application.


2019 ◽  
Vol 16 (6) ◽  
pp. 50-59
Author(s):  
O. P. Trubitsina ◽  
V. N. Bashkin

The article is devoted to the consideration of geopolitical challenges for the analysis of geoenvironmental risks (GERs) in the hydrocarbon development of the Arctic territory. Geopolitical risks (GPRs), like GERs, can be transformed into opposite external environment factors of oil and gas industry facilities in the form of additional opportunities or threats, which the authors identify in detail for each type of risk. This is necessary for further development of methodological base of expert methods for GER management in the context of the implementational proposed two-stage model of the GER analysis taking to account GPR for the improvement of effectiveness making decisions to ensure optimal operation of the facility oil and gas industry and minimize the impact on the environment in the geopolitical conditions of the Arctic.The authors declare no conflict of interest


2019 ◽  
Author(s):  
Chem Int

This study investigated the impact of Quality Management System (QMS) on effective service delivery in Oil and Gas Servicing Companies in selected firms in Port Harcourt, Nigeria. The opinion of 50 respondents were sampled using questionnaires, interviews as well as observation from journals and texts used in this work to examine the Quality Management System (QMS) of the selected firms. Using simple percentages and the Chi-square (X2) test of hypotheses, it was hypothetically established that the implementation of QMS practices, has impacted the work process, procedure and improvement on quality over the years in the Oil and Gas Servicing companies in Port Harcourt Nigeria. The research identified an adopted use of Failure Mode and Effect Analysis (FMEA) tool as a continual quality improvement initiative developed in the local content oil and gas servicing operation for equipment handling, management and to drive sustained improved performance quality processes as a key driver of a progressive that will place local content companies as an options for producing companies and at par with multinational oil and gas companies.


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