Instability Characteristic of a Single-Stage Centrifugal Compressor Exposed to Dry and Wet Gas

2012 ◽  
Author(s):  
Trond G. Grüner ◽  
Lars E. Bakken
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Pressure Sensors ◽  
Ambient Air ◽  
Single Stage ◽  
Performance Characteristics ◽  
Test Facility ◽  
Wet Gas ◽  
And Performance ◽  
The Impact

An experimental investigation was conducted to determine the instability and performance characteristics of a single-stage centrifugal compressor exposed to wet gas. The compressor was tested at different rotational speeds and low gas mass fractions (GMFs) in an open-loop test facility with ambient air and water. The stage consisted of a shrouded impeller with a vaneless diffuser surrounded by a symmetrical circular volute with increasing cross-sectional area. Liquid was uniformly injected into the impeller eye through multiple nozzles mounted in the inlet pipe. High-response dynamic pressure sensors flush-mounted in the diffuser were used to identify instability inception and evolution. Changes in the instability and pressure ratio characteristics at different GMFs and rotational speeds were revealed. Analysis with reference to dry gas was performed. Visual observation of the wet gas surge process at the inlet is described. Results and analysis obtained from the experimental investigation on wet gas instability are presented. The investigation contributed to knowledge concerning the impact of wet gas on the instability and performance characteristics.

Wet Gas Performance of a Single Stage Centrifugal Compressor

2008 ◽  
Author(s):  
O̸yvind Hundseid ◽  
Lars E. Bakken ◽  
Trond G. Gru¨ner ◽  
Lars Brenne ◽  
Tor Bjo̸rge
Keyword(s):  
Performance Analysis ◽  
Centrifugal Compressor ◽  
Single Stage ◽  
Water Mixture ◽  
Performance Parameters ◽  
Operating Range ◽  
Wet Gas ◽  
Gas Compression ◽  
Compressor Performance ◽  
The Impact

This paper evaluates the performance analysis of wet gas compression. It reports the performance of a single stage gas centrifugal compressor tested on wet gas. These tests were performed at design operating range with real hydrocarbon mixtures. The gas volume fraction was varied from 0.97 to 1.00, with alternation in suction pressure. The range is representative for many of the gas/condensate fields encountered in the North Sea. The machine flow rate was varied to cover the entire operating range. The compressor was also tested on a hydrocarbon gas and water mixture to evaluate the impact of liquid properties on performance. No performance and test standards currently exist for wet gas compressors. To ensure nominated flow under varying fluid flow conditions, a complete understanding of compressor performance is essential. This paper gives an evaluation of real hydrocarbon multiphase flow and performance parameters as well as a wet gas performance analysis. The results clearly demonstrate that liquid properties influence compressor performance to a high degree. A shift in compressor characteristics is observed under different liquid level conditions. The results in this paper confirm the need for improved fundamental understanding of liquid impact on wet gas compression. The evaluation demonstrates that dry gas performance parameters are not applicable for wet gas performance analysis. Wet gas performance parameters verified against results from the tested compressor is presented.

Investigation on the Impact of Circumferential Grooves on Aerodynamic Centrifugal Compressor Performance

2015 ◽  
Author(s):  
Simon Bareiß ◽  
Damian M. Vogt ◽  
Elias Chebli
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Surface Friction ◽  
Detailed Examination ◽  
Test Facility ◽  
Groove Surface ◽  
And Performance ◽  
Cfd Analyses ◽  
The Impact

Casing treatments are widely used in compressors for increasing range, stability and aerodynamic performance. However, applications in centrifugal compressors, as commonly used in turbochargers, are rare and mostly applied at the inlet region in terms of bleed slots. This paper presents the application of circumferential grooves, which are known to increase stability and performance in axial compressors, to the rear part of the impeller shroud casing in a centrifugal compressor. Experimental and numerical investigations of three different configurations have been performed and compared with the initial geometry. Experiments were conducted on a hot gas test facility where static pressure and temperature measurements up- and downstream of the compressor were acquired. The results indicate only small changes in operating range except for one speedline, where a considerable improvement is observed. Efficiency remains nearly unaffected for all configurations whereas the pressure ratio is increased at some operating points. For detailed examination of the compressor flow field, CFD analyses were conducted using steady-state RANS calculations. Structured meshes with node to node connections were used to suspend any possible influences stemming from interfaces in regions of interest. Validation with test data yields good agreement concerning choke margin and gradient trends. CFD results confirm that the investigated configurations of circumferential grooves have only small impact on efficiency and pressure ratio. Investigations on the mechanism which balances the additional losses due to increased groove surface friction and increases pressure rise are presented.

Numerical Investigation of the Effect of Diffuser and Volute Design Parameters on the Performance of a Centrifugal Compressor Stage

2016 ◽  
Author(s):  
Lei Yu ◽  
William T. Cousins ◽  
Feng Shen ◽  
Georgi Kalitzin ◽  
Vishnu Sishtla ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Gas Flow ◽  
Pressure Rise ◽  
Design Parameters ◽  
Compressor Stage ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Centrifugal Stage ◽  
And Performance ◽  
The Impact

In this effort, 3D CFD simulations are carried out for real gas flow in a refrigeration centrifugal compressor. Both commercial and the in-house CFD codes are used for steady and unsteady simulations, respectively. The impact on the compressor performance with various volute designs and diffuser modifications are investigated with steady simulations and the analysis is focused on both the diffuser and the volute loss, in addition to the flow distortion at impeller exit. The influence of the tongue, scroll diffusion ratio, diffuser length, and cross sectional area distribution is examined to determine the impact on size and performance. The comparisons of total pressure loss, static pressure recovery, through flow velocity, and the secondary flow patterns for different volute designs show that the performance of the centrifugal compressor depends upon how well the scroll portion of the volute collects the flow from the impeller and achieves the required pressure rise with minimum flow losses in the overall diffusion process. Finally, the best design is selected based on compressor stage pressure rise and peak efficiency improvement. An unsteady simulation of the full wheel compressor stage was carried out to further examine the interaction of impeller, diffuser and the volute. The unsteady flow interactions are shown to have a major impact on the performance of the centrifugal stage.

Wet Gas Impeller Test Facility

2010 ◽  
Author(s):  
Trond G. Gru¨ner ◽  
Lars E. Bakken
Keyword(s):  
Oil And Gas ◽  
Fluid Dynamic ◽  
Open Loop ◽  
Gas Production ◽  
Test Facility ◽  
Atmospheric Conditions ◽  
Oil And Gas Production ◽  
Wet Gas ◽  
Inlet Conditions ◽  
The Impact

The development of wet gas compressors will enable increased oil and gas production rates and enhanced profitable operation by subsea well-stream boosting. A more fundamental knowledge of the impact of liquid is essential with regard to the understanding of thermodynamic and fluid dynamic compressor behavior. An open-loop impeller test facility was designed to investigate the wet gas performance, aerodynamic stability, and operation range. The facility was made adaptable for different impeller and diffuser geometries. In this paper, the wet gas test facility and experimental work concerning the impact of wet gas on a representative full-scale industrial impeller are presented. The centrifugal compressor performance was examined at high gas volume fractions and atmospheric inlet conditions. Air and water were used as experimental fluids. Dry and wet gas performance was experimentally verified and analyzed. The results were in accordance with previous test data and indicated a stringent influence of the liquid phase. Air/water tests at atmospheric conditions were capable of reproducing the general performance trend of hydrocarbon wet gas compressor tests at high pressure.

Experimental Investigation of the Effect of Purge Flow on Film Cooling Effectiveness on a Rotating Turbine With Non-Axisymmetric Endwall Contouring

2013 ◽  
Author(s):  
M. Rezasoltani ◽  
M. T. Schobeiri ◽  
J. C. Han
Keyword(s):  
Experimental Investigation ◽  
Film Cooling ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Turbine Efficiency ◽  
Purge Flow ◽  
Endwall Contouring ◽  
And Performance ◽  
Cooling Loops ◽  
The Impact

The impact of the purge flow injection on aerodynamics and film cooling effectiveness of a three-stage high pressure turbine with non-axisymmetric endwall contouring has been experimentally investigated. As a continuation of the previously published work involving stator-rotor gap purge cooling, this study investigates film cooling effectiveness on the first stage rotor contoured platform due to a coolant gas injection. Film cooling effectiveness measurements are performed on the rotor blade platform using a pressure sensitive paint (PSP) technique. The present study examines, in particular, the film cooling effectiveness due to injection of coolant from the rotor cavity through the circumferential gap between the first stator followed by the first rotor. Efficiency and performance experiments were conducted with and without cooling injection to show (a) the impact of endwall contouring on the turbine efficiency and (b) the impact of film cooling injection in association with the endwall contouring. The experimental investigation is carried out in a three-stage turbine facility at the Turbomachinery Performance and Flow Research Laboratory (TPFL) at Texas A&M University. Its rotor includes non-axisymmetric endwall contouring on the first and second rotor row [1]. The turbine has two independent cooling loops. Film cooling effectiveness measurements are performed for three coolant-to-mainstream mass flow ratios of 0.5%, 1.0% and 1.5%. Film cooling data is also obtained for three rotational speeds, 3000 rpm (reference condition), 2550 rpm and 2400 rpm and compared with non-contoured endwall data.

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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