Upstream and Midstream Compression Applications: Part 2—Implications on Operation and Control of the Compression Equipment

2012 ◽  
Author(s):  
Rainer Kurz ◽  
Robert C. White ◽  
Klaus Brun
Keyword(s):  
Pressure Ratio ◽  
System Behavior ◽  
High Pressure Ratio ◽  
System Operator ◽  
Process System ◽  
Multiple Unit ◽  
And Control ◽  
The Impact ◽  
System Characteristics ◽  
Wide Operating

Different upstream and midstream applications lead to different compression system characteristics and control requirements that are the result of compressor requirements (eg high pressure ratio, wide operating range) and the process requirements. Multiple unit installations, or installations with multiple compressors per train require specific process control considerations to match the compressors with the process system behavior and the objectives of the station or system operator. This paper explains the impact of the interaction between system characteristics and compressor characteristics, both under steady state and transient conditions. Also considered are concepts to optimize and control the units.

scholarly journals Meridional Considerations of the Centrifugal Compressor Development

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Centrifugal Compressor ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Angle Distribution ◽  
High Pressure Ratio ◽  
Structure Reliability ◽  
Compressor Performance ◽  
Meridional Profile ◽  
Compressor Efficiency ◽  
Wide Operating

Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of the blades and the meridional profile are very important contributions of compressor performance and structure reliability. This paper presents some recent studies of meridional impacts of the compressor. Studies indicated that the meridional profiles of the impeller impact the overall compressor efficiency and pressure ratio at the same rotational speed. Proper meridional profiles can improve the compressor efficiency and increase the overall pressure ratio at the same blade back curvature.

Numerical Investigation of Low Solidity Vaned Diffuser Performance in a High-Pressure Centrifugal Compressor: Part I — Influence of Vane Solidity

2007 ◽  
Author(s):  
JongSik Oh ◽  
Giri L. Agrawal
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Limited Range ◽  
Design Flow ◽  
Design Parameters ◽  
Moderate Pressure ◽  
Vaned Diffuser ◽  
High Pressure Ratio ◽  
Wide Operating

The LSD (Low Solidity Diffuser) is becoming popular in most industrial centrifugal compressor designs because it is found to offer a wide operating flow range while maintaining a similar level of efficiency as in case of conventional vaned diffusers. Most related studies have been for low or moderate pressure ratio machines providing a limited range of design information for high-pressure ratio compressors. As a first step forward information of design parameters, a numerical CFD investigation was applied to a high-pressure industrial centrifugal compressor of design total-to-static pressure ratio of 4.0 with LSDs of NACA65-series profiles whose solidity varies from 0.452 to 0.968 in 5 cases with all the other design parameters fixed. Near design flow, the case of 0.839 solidity has the highest isentropic total-to-static efficiency. Other performance changes are accordingly investigated.

Process Control for Compression Systems

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Rainer Kurz ◽  
Klaus Brun
Keyword(s):  
Steady State ◽  
Process Control ◽  
Centrifugal Compressor ◽  
Variable Speed ◽  
Transient Conditions ◽  
Process Dynamics ◽  
And Control ◽  
The Impact ◽  
System Characteristics

This paper discusses the interaction between a centrifugal compressor and the process, and as a result, the control requirements for centrifugal compressor packages. The focus is on variable speed, upstream, and midstream applications. The impact of the interaction between system characteristics and compressor characteristics both under steady-state and transient conditions is explained. Also considered are the concepts to optimize and control the units. Special attention is given to the issue of surge avoidance. Additionally, the impact of the process and how the process dynamics interact with the compressor is analyzed, categorized, and explained.

Impact of Main and Splitter Blade Leading Edge Contour on the Performance of High Pressure Ratio Centrifugal Compressors

2014 ◽  
Author(s):  
Rodrigo R. Erdmenger ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Centrifugal Compressors ◽  
Operating Range ◽  
High Pressure Ratio ◽  
The Impact ◽  
Blade Leading Edge

The impact of leading edge sweep in an attempt to reduce shock losses and extend the stall margin on axial compressors has been extensively studied, however only a few studies have looked at understanding the impact of leading edge contouring on the performance of centrifugal compressors. The present work studies the impact of forward and aft sweep on the main and splitter blade leading edge of a generic high flow coefficient and high pressure ratio centrifugal compressor design and the impact on its overall peak efficiency, pressure ratio and operating range. The usage of aft sweep on the main blade led to an increase of the pressure ratio and efficiency, however it also led to a reduction of the stable operating range of the impeller analyzed. The forward sweep cases analyzed where the tip leading edge was displaced axially forward showed a slight increase in pressure ratio, and a significant increase on operating range. The impact of leading edge sweep on the sensitivity of the impeller performance to tip clearance was also studied. The impeller efficiency was found to be less sensitive to an increase of tip clearance for both aft and forward sweep cases studied. The forward sweep cases studied also showed a reduced sensitivity from operating range to tip clearance. The studies conducted on the splitter leading edge profile indicate that aft sweep may help to increase the operating range of the impeller analyzed by up to 16% while maintaining similar pressure ratio and efficiency characteristics of the impeller. The improvement of operating range obtained with the leading edge forward sweep and splitter aft sweep was caused by a reduction of the interaction of the tip vortex of the main blade with the splitter tip, and a reduction of the blockage caused by this interaction.

Aerodynamic Investigation of a High Pressure Ratio Turbo-Expander for Organic Rankine Cycle Applications

2012 ◽  
Author(s):  
Michele Marconcini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Alberto Scotti Del Greco ◽  
Roberto Biagi
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Aerodynamic Performance ◽  
Performance Estimation ◽  
Primary Concern ◽  
Viscous Effects ◽  
Cfd Modelling ◽  
Mechanical Integrity ◽  
High Pressure Ratio ◽  
The Impact

The design of radial-inflow turbines usually relies on one-dimensional or mean-line methods. While these approaches have so far proven to be quite effective, they can not assist the designer in coping with some important issues, such as mechanical integrity and complex flow features. Turbo-expanders are in general characterized by fully three-dimensional flow fields, strongly influenced by viscous effects and passage curvature. In particular, for high pressure ratio applications, such as in organic Rankine cycles, supersonic flow conditions are likely to be reached, thus involving the formation of a shock pattern which governs the interaction between nozzle and wheel components. The nozzle shock waves are periodically chopped by the impeller leading edge, and the resulting unsteady interaction is of primary concern for both mechanical integrity and aerodynamic performance. This work is focused on the aerodynamic issues and addresses some key aspects of the CFD modelling in the numerical analysis of turbo-expanders. Calculations were carried out by adopting models with increasing level of complexity, from the classical steady-state approach to the full-stage, time-accurate one. Results are compared in details and the impact of the computational model on the aerodynamic performance estimation is discussed.

The Fouling of Axial Flow Compressors: Causes, Effects, Susceptibility, and Sensitivity

2009 ◽  
Author(s):  
Cyrus B. Meher-Homji ◽  
Mustapha Chaker ◽  
Andrew F. Bromley
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Simulation Analysis ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Design Parameters ◽  
Comprehensive Treatment ◽  
Performance Deterioration ◽  
And Control ◽  
The Impact

Increased fuel costs have created a strong incentive for gas turbine operators to understand, minimize and control performance deterioration. The most prevalent deterioration problem faced by gas turbine operators is compressor fouling. Fouling causes a drop in airflow, pressure ratio and compressor efficiency, resulting in a “re-matching” of the gas turbine and compressor and a drop in power output and thermal efficiency. This paper addresses the causes and effects of fouling and provides a comprehensive treatment of the impact of salient gas turbine design parameters on the susceptibility and sensitivity to compressor fouling. Simulation analysis of ninety two (92) gas turbines of ranging from a few kW to large engines rated at greater than 300 MW has been conducted. It is hoped that this paper will provide practical information to gas turbine operators.

Effect of Recirculation Device With Counter Swirl Vane on Performance of High Pressure Ratio Centrifugal Compressor

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Hideaki Tamaki
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Recirculation Flow ◽  
New Device ◽  
Operating Range ◽  
High Pressure Ratio ◽  
Swirl Vane ◽  
Rotational Direction ◽  
Wide Operating

Centrifugal compressors used for turbochargers need to achieve a wide operating range. The author has developed a high pressure ratio centrifugal compressor with pressure ratio 5.7 for a marine use turbocharger. In order to enhance operating range, two different types of recirculation devices were applied. One is a conventional recirculation device. The other is a new one. The conventional recirculation device consists of an upstream slot, bleed slot and the annular cavity which connects both slots. The new recirculation device has vanes installed in the cavity. These vanes were designed to provide recirculation flow with negative preswirl at the impeller inlet, a swirl counterwise to the impeller rotational direction. The benefits of the application of both of the recirculation devices were ensured. The new device in particular, shifted surge line to a lower flow rate compared to the conventional device.

Process Control for Compression Systems

2017 ◽  
Author(s):  
Rainer Kurz ◽  
Klaus Brun
Keyword(s):  
Steady State ◽  
Process Control ◽  
Centrifugal Compressor ◽  
Variable Speed ◽  
Transient Conditions ◽  
Process Dynamics ◽  
And Control ◽  
The Impact ◽  
System Characteristics

The paper discusses the interaction between a centrifugal compressor and the process, and as a result, the control requirements for centrifugal compressor packages. The focus is on variable speed, upstream and midstream applications. The impact of the interaction between system characteristics and compressor characteristics, both under steady state and transient conditions is explained. Also considered are concepts to optimize and control the units. Special attention is given to the issue of surge avoidance. Additionally, the impact of the process and how the process dynamics interact with the compressor is analyzed, categorized, and explained.

The Effect of Tip Clearance on the Performance of Contra-Rotating Compressor

2012 ◽  
Author(s):  
Limin Gao ◽  
Xiaojun Li ◽  
Xudong Feng ◽  
Bo Liu
Keyword(s):  
Pressure Ratio ◽  
Weight Ratio ◽  
Aircraft Engine ◽  
Back Pressure ◽  
Tip Clearance ◽  
Stall Margin ◽  
Operating Range ◽  
Important Approach ◽  
The Impact ◽  
Wide Operating

Contra-rotating technology has been considered as an important approach to further improve the thrust-weight ratio of aircraft engine because of its structure and aerodynamic superiority. In the present work, the impact of tip clearance on the performance of a CRAC which consist of two counter-rotating rotors is investigated numerically. To detect the stall margin of CRAC exactly, the back pressure dichotomy method is developed, the grid indepence is verified and the performance is measured. A large number computation is carried out to explore the influence of tip clearance on the operating range of contra-rotating compressor. Finally the flow filed near the tip clearance is analyzed to find the relation between the tip clearance and the first stall rotor. The result shows: (1) Efficiency and pressure ratio decrease with the tip clearance size increased, but there is an optimal tip clearance size corresponding to a relative wide operating range. (2) The first stall stage of contra-rotating compressor varies with the tip clearance size increases. For the present CRAC, ROT2 is the first stall stage with the tip clearance size no greater than 0.5mm, while the ROT1 is the first stall stage if the tip clearance size greater than 0.5mm.

scholarly journals The Britalus Brayton Cycle Engine

1984 ◽  
Author(s):  
R. Decher
Keyword(s):  
Pressure Ratio ◽  
Brayton Cycle ◽  
Part Load ◽  
High Pressure Ratio ◽  
Positive Displacement ◽  
Bearing Contact ◽  
Engine Design ◽  
Compression And Expansion ◽  
Steady Combustion ◽  
The Impact

The Britalus Engine concept under development by Combustion Research & Technology, Inc. (CR&Ti) is a gas turbine-like Brayton cycle engine whose physical characteristic is that a unique design is used for the compressor and the expander. These components achieve their function by positive displacement wherein pistons located within a rotor are forced to execute simple harmonic motion through bearing contact with an outer three-lobed cam. It is shown that this arrangement has the advantage that practical designs for engine sizes ranging from as small as 10 kw to 1000 kw with steady combustion are possible. The high compression and expansion efficiencies of these components incorporated in a simple high pressure ratio cycle allow contemplation of the design of light, rugged and efficient engines for a wide variety of applications. A realistic evaluation of a new engine requires identification and magnitude determination of the performance limiting loss mechanisms and an understanding of the means for power control. This paper is a description of the compressor and expander components, and the means used for cycle pressure variation by modification of the compressor geometry. The part-load characteristics of the engine and the impact of the requirement for part-load operation on the engine design are described.

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