A New Inlet Distortion and Pressure Loss Based Design of an Intake System for Stationary Gas Turbines

2013 ◽  
Author(s):  
Jose Rodriguez ◽  
Stephan Klumpp ◽  
Thomas Biesinger ◽  
James O’Brien ◽  
Tobias Danninger
Keyword(s):  
Gas Turbines ◽  
Inlet System ◽  
Inlet Distortion ◽  
Surge Margin ◽  
Compressor Surge ◽  
Compressor Inlet ◽  
The Face ◽  
Flow Quality ◽  
Inlet Manifold ◽  
Distortion Parameters

This paper presents a new design for a Compressor Inlet Manifold (CIM) for a land-based power generation Gas Turbine (turbine). The CIM is the component of the Inlet System (IS) that is directly connected to the turbine via the Compressor Inlet Case (CIC). The design philosophy is to use low fidelity but fast and automated CFD (Computational Fluid Dynamics) for design iterations and then confirm the design with detailed higher accuracy CFD before proceeding to engine tests. New design features include contouring the wall to minimize areas of flow separation and associated unsteadiness and losses, and improvement of the flow quality into the compressor. The CIM in a land-based turbine acts as a nozzle whereas the inlet of an aircraft acts as a diffuser. The flow also enters the CIM at 90 deg to the engine axis. This leads to a pair of counter rotating vortices at the compressor inlet. Three main sources of flow distortions at the face of the compressor are identified: flow separations at outer walls of the IS and CIM struts and the counter rotating vortices. The higher accuracy CFD analysis including the complete IS, CIM and the first compressor stage, simulates the effect of these distortions on the compressor front stage at design conditions. A range of inlet distortion parameters are used to evaluate the inlet design. The well known DC60 based criterion derived from aircraft engines and other less known but published parameters are able to give an indication of how the compressor surge margin of stationary gas turbines is affected.

T100 Micro Gas Turbine Converted to Full Humid Air Operation: Test Rig Evaluation

2014 ◽  
Author(s):  
Ward De Paepe ◽  
Marina Montero Carrero ◽  
Svend Bram ◽  
Francesco Contino
Keyword(s):  
Energy Transfer ◽  
Gas Turbines ◽  
Water Injection ◽  
Test Rig ◽  
Humid Air ◽  
Limited Energy ◽  
Surge Margin ◽  
Heat Demand ◽  
Compressor Surge ◽  
Efficiency Increase

Micro Gas Turbines (mGTs) are very cost effective in small-scale Combined Heat and Power (CHP) applications. By simultaneously producing electric and thermal power, a global CHP efficiency of 80 % can be reached. However the low electric efficiency of 30 % makes the mGT profitability strongly dependent on the heat demand. This makes the mGT less attractive for applications with a non-continuous heat demand like domestic applications. Turning the mGT into a micro Humid Air Turbine (mHAT) is a way to decouple the power production from the heat demand. This new approach allows the mGT to keep running with water injection and thus higher electric efficiency during periods with no or lower heat demand. Simulations of the mHAT predicted a substantial electric efficiency increase due to the introduction of water in the cycle. The mHAT concept with saturation tower was however never tested experimentally. In this paper, we present the results of our first experiments on a modified Turbec T100 mGT. As a proof of concept, the mGT has been equipped with a spray saturation tower to humidify the compressed air. The primary goal of this preliminary experiments was to evaluate the new test rig and identify its shortcomings. The secondary goal was to gain insight in the mHAT control, more precisely the start-up strategy. Two successful test runs of more than 1 hour with water injection at 60 kWe were performed, resulting in stable mGT operation at constant rotation speed and pressure ratio. Electric efficiency was only slightly increased from 24.3 % to 24.6 % and 24.9 % due to the limited amount of injected water. These changes are however in the range of the accuracy on the measurements. The major shortcomings of the test rig were compressor surge margin reduction and the limited energy transfer in the saturation tower. Surge margin was reduced due to a pressure loss over the humidification unit and piping network, resulting in possible compressor surge. Bleeding air to increase surge margin was the solution to prevent compressor surge, but it lowers the electric efficiency by approximately 4 % absolute. The limited energy transfer was a result of a low water injection temperature and mass flow rate. The low energy transfer causes the limited efficiency increase. The first experiments on the mHAT test rig indicated its shortcomings but also its potential. Stable mGT operation was obtained and electric efficiency remained stable. By increasing the amount of injected water, the electric efficiency can be increased.

Effect of Exit Pressure Pulsation on the Performance and Stability Limit of a Turbocharger Centrifugal Compressor

2016 ◽  
Author(s):  
Maria Esperanza Barrera-Medrano ◽  
Peter Newton ◽  
Ricardo Martinez-Botas ◽  
Srithar Rajoo ◽  
Isao Tomita ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Flow Instability ◽  
Combustion Engine ◽  
Stability Limit ◽  
Intermittent Flow ◽  
Limited Information ◽  
Surge Margin ◽  
Compressor Surge ◽  
Compressor Inlet ◽  
The Stability

It is well known that compressor surge imposes a significant limit on the flow range of a turbocharged internal combustion engine. The centrifugal compressor is commonly placed upstream of the inlet manifold and hence, it is exposed to the intermittent flow regime of the inlet valves. Surge phenomena has been well studied over the past decades, there still remains limited information with regards to the unsteady impact caused by the inlet valves. This study presents an experimental evaluation of such a situation. Engine representative pulses are created by a downstream system comprising a large volume, two rotating valves, a throttle valve and the corresponding pipe network. Different pulsation levels are characterized by means of their frequency and the corresponding amplitude at the compressor inlet. The stability limit of the system under study is evaluated with reference to the parameter B proposed by Greitzer [7–9]. B describes the dynamics of the compression system in terms of volume, area, equivalent length and compressor tip speed as well as the Helmholtz frequency of the system. For a given compressor, as B goes beyond a critical value, the system will exhibit surge as the result of the flow instability progression. The reduced frequency analysis shows that the scroll-diffuser operates in an unsteady regime, while the impeller is nearly quasi-steady. In the vicinity of the surge point, under a pulsating flow, the instantaneous operation of the compressor showed significant excursions into the unstable side of the surge line. Furthermore, it has been found that the presence of a volume in the system has the greatest effect on the surge margin of the compressor under the unsteady conditions.

Surge Prevention Techniques for a Turbocharged Solid Oxide Fuel Cell Hybrid System

2021 ◽  
Author(s):  
Luca Mantelli ◽  
Mario L. Ferrari ◽  
Alberto Traverso
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbines ◽  
Control Strategies ◽  
Solid Oxide ◽  
Pollutant Emissions ◽  
Inlet Temperature ◽  
Oxide Fuel ◽  
Surge Margin ◽  
Compressor Inlet

Abstract Pressurized solid oxide fuel cell systems are one of the most promising technologies to achieve high efficiencies and reduce pollutant emissions. This study focuses on an innovative layout, based on an automotive turbocharger, which improves cost effectiveness at small size (<100 kW), despite reducing slightly the efficiency compared to micro gas turbines based layouts. This turbocharged system poses two main challenges. On one side, the absence of an electrical generator does not allow the direct control of the rotational speed. On the other side, the large volume of the fuel cell stack between compressor and turbine alters the dynamic behavior of the turbocharger during transients, increasing the risk of compressor surge. The pressure oscillations associated with surge are particularly detrimental for the system and could damage the materials of the fuel cells. The aim of this paper is to investigate different techniques to drive the operative point of the compressor far from the surge condition when needed, increasing its reliability. Using a system dynamic model, developed with the TRANSEO tool by TPG, the effect of different anti-surge solutions is simulated: (i) water spray at compressor inlet, (ii) compressor fogging, (iii) air bleed, (iv) recirculation and (iv) ejector-aided recirculation at compressor intake. The system is simulated with two different control strategies, i.e. constant fuel mass flow and constant turbine inlet temperature. Different solutions are evaluated based on surge margin behavior, both in the short and long terms, but also monitoring other relevant physical quantities of the system.

Inlet Distortion Effects in Axial Compressors

1980 ◽  
Vol 102 (1) ◽  
pp. 7-13 ◽  
Author(s):  
A. H. Stenning
Keyword(s):  
Gas Turbines ◽  
Total Pressure ◽  
Free Flow ◽  
Flow Conditions ◽  
Inlet Flow ◽  
Axial Compressors ◽  
Inlet Distortion ◽  
Compressor Inlet ◽  
Inlet Conditions

Although uniform inlet conditions are highly desirable and system designers attempt to insure distortion-free flow entering compressors, situations frequently arise in which substantial total pressure, velocity, and angle variations exist at the compressor inlet. Aircraft gas turbines are particularly prone to inlet distortion problems due to changes in aircraft attitude and the effect of the airframe on the inlet flow conditions, but industrial insallations may also suffer from inlet distortion in cases where poorly designed bends have been installed upstream of the compressor. In this paper, problems associated with inlet distortion are discussed and some of the simpler techniques for analyzing the effects of circumferential inlet distortion are presented.

Investigation of Different Surge Handling Strategies and its Impact on the Cogeneration Performance for a Single-Shaft Gas Turbine Operating on Syngas

2015 ◽  
Author(s):  
Javier Beltran Montemayor ◽  
Lars-Uno Axelsson
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Rate ◽  
Outlet Temperature ◽  
Advantages And Disadvantages ◽  
Fuel Flow ◽  
Surge Margin ◽  
Compressor Surge ◽  
Increasing Demand

The increasing demand for decentralized power has led to a growing interest in smaller gas turbines for cogeneration applications. One benefit of decentralized power generation is the possibility to utilize fuels that are locally available. One example is syngas, which has gained increasing interest during the recent years. Compared to natural gas the syngas fuels have a large amount of dilutants, such as nitrogen and carbon dioxide, which results in a very low energy density. Hence, significant larger fuel flow is required. However, the added fuel flow will decrease the compressor surge margin and eventually drive the compressor towards surge. Several methods exist to address this issue including variable inlet guide vanes, increased turbine throat area, compressor bleeding and decreased combustor outlet temperature. This paper examines the operability of a generic all-radial single-shaft gas turbine in the 2 MW power range when running on syngas with different heating values. The above methods to combat the decreased surge margin will be analyzed using detailed cycle simulations and their advantages and disadvantages will be discussed. It was found that the increased throat area is the most beneficial of the four methods. The net power output is nearly the same as for natural gas operation and the heat rate is the lowest of the four methods.

Experimental Investigation of Inlet Distortion in a 4.5-Stage Axial Compressor

2020 ◽  
Author(s):  
Oliver Reutter ◽  
Gerd Enders ◽  
Theo Dabrock ◽  
Andreas Peters
Keyword(s):  
Experimental Investigation ◽  
Gas Turbines ◽  
Axial Compressor ◽  
Metal Plate ◽  
Axial Compressors ◽  
Transonic Compressor ◽  
Inlet Distortion ◽  
Surge Margin ◽  
Small Influence ◽  
Compressor Map

Abstract Inlet distortion is a subject of increasing interest in compressors over the last years. Circumferential inhomogeneities can significantly influence the behavior and the aeroelastic response of transonic compressors in gas turbines in the field of airplane propulsion as well as power generation. The circumferential inhomogeneities can result from boundary layer ingestion as planned in many future airplane concepts or from restrictions of the space available leading to short aerodynamically unfavorable intakes. As modern front rows of axial compressors react more and more sensitive to inhomogeneities because of the thinner profiles in the transonic flow regime, understanding the behavior is vital. Therefore, an experimental investigation of the inlet distortion effects on a 4.5 stage axial transonic compressor, Rig250, which is representative of the front stages of a modern high pressure compressor, has been investigated at DLR Cologne. The inhomogeneity is a total pressure distortion which is applied to the inflow upstream of the strut and the swan neck. The distortion is achieved by a perforated metal plate which can be rotated by 360° at its position. Thereby traverse measurements are possible, which allow a better understanding of the effects of the flow as the sensor positions on the casing and on the blades and vanes are fixed. As these traverses take longer time for measuring only some points are measured with traverses. The compressor has been tested with and without this inlet distortion to get a direct comparison. On the compressor map the 100 % speed line up to surge has been investigated. The inlet distortion shows only a small influence on the surge margin.

A Study on Power Uprating of a Steam Injected Gas Turbine Cogeneration System by Compressor Discharge Air Bypass

2013 ◽  
Author(s):  
Do Won Kang ◽  
Hyuck Jun Jang ◽  
Tong Seop Kim
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Energy Demand ◽  
Steam Injection ◽  
Injection Rate ◽  
Heat Output ◽  
Operational Parameter ◽  
Surge Margin ◽  
Exhaust Heat ◽  
Compressor Surge

Gas turbines are widely used for cogeneration systems. In general, electricity and heat demands are not constant throughout the year. In cooling seasons, generally, heat demand decreases but electricity demand increases. In small gas turbine cogeneration systems, steam injection is a good way to respond to the demand variation. However, steam injection causes compressor discharge pressure to rise. This means a reduction in compressor surge margin, which is a critical operational parameter. Hence, even though thermal energy demand decreases considerably as is the case in cooling seasons, the surplus exhaust heat cannot be utilized for the steam injection in the conventional operation. In this study, a modified steam injected operation is suggested, which uprates electric power output without damaging a minimum allowable surge margin. This can be realized by extracting some of compressor discharge air and supplying it to the turbine exhaust side. The modified operation allows more steam to be injected into the combustor in comparison to the conventional steam injected operation while it guarantees the same compressor surge margin. The modified operation concept provides another merit of modulating the heat to power generation ratio by controlling both the amount of air bypass and the steam injection rate. In particular, pure power generating operation, where full amount of generated steam is injected and thus no heat output is available, is possible without decreasing the surge margin below a desired minimum value.

The Effect of Inlet Distortion on the Performance Characteristics of a Centrifugal Compressor

1983 ◽  
Vol 105 (2) ◽  
pp. 223-230 ◽  
Author(s):  
I. Ariga ◽  
N. Kasai ◽  
S. Masuda ◽  
Y. Watanabe ◽  
I. Watanabe
Keyword(s):  
Centrifugal Compressor ◽  
Total Pressure ◽  
Performance Characteristics ◽  
Performance Tests ◽  
Velocity Measurements ◽  
Test Rig ◽  
Low Speed ◽  
Inlet Distortion ◽  
Surge Margin ◽  
The Given

The present paper concerns itself with the effects of total pressure (and thus velocity) distortion on performance characteristics and surge margin of centrifugal compressors. Both radial and circumferential distortions were investigated. The performance tests as well as the velocity measurements within the impeller passages were carried out with a low-speed compressor test rig with the inlet honeycomb as the distortion generators and compared with the case of “no distortion” as a datum. The results indicated that the inlet distortion exerted unfavorable influences on the efficiency and the surge margin of the given compressor, though the influence of the radial distortion was much stronger than that of the circumferential one. Various distortion indices were further examined in order to correlate the performance to the inlet distortion.

Prewhirl an Added Degree of Freedom to the Designer of Small Single-Shaft Gas Turbines

1967 ◽  
Vol 89 (1) ◽  
pp. 83-85
Author(s):  
A. R. Shouman
Keyword(s):  
Gas Turbines ◽  
Degree Of Freedom ◽  
Design Specifications ◽  
Compressor Inlet ◽  
Design Requirements

The possibility of the advantageous use of adjustable guidevanes in the compressor inlet for the control of single-shaft gas turbines is discussed. Considering certain design specifications that are impossible to be met by a fixed-geometry, single-shaft machine, it is pointed out how the design specifications can be met utilizing an inlet guidevane system. This is merely used as an example to point out the possible merits of such a system and that it may allow the designer to meet some extraordinary design requirements.

scholarly journals Surge and Stall Detection Using Acoustic Analysis for Gas Turbine Hybrid Cycles

2019 ◽  
Author(s):  
Keishaly Cabrera Cruz ◽  
Paolo Pezzini ◽  
Lawrence Shadle ◽  
Kenneth M. Bryden
Keyword(s):  
Gas Turbine ◽  
Natural Frequencies ◽  
Acoustic Analysis ◽  
General Nature ◽  
Acoustic Sensors ◽  
Frequency Range ◽  
Surge Margin ◽  
Compressor Surge ◽  
Surge Line ◽  
Transient Operations

Abstract Compressor dynamics were studied in a gas turbine – fuel cell hybrid power system having a larger compressor volume than traditionally found in gas turbine systems. This larger compressor volume adversely affects the surge margin of the gas turbine. Industrial acoustic sensors were placed near the compressor to identify when the equipment was getting close to the surge line. Fast Fourier transform (FFT) mathematical analysis was used to obtain spectra representing the probability density across the frequency range (0–5000 Hz). Comparison between FFT spectra for nominal and transient operations revealed that higher amplitude spikes were observed during incipient stall at three different frequencies, 900, 1020, and 1800 Hz. These frequencies were compared to the natural frequencies of the equipment and the frequency for the rotating turbomachinery to identify more general nature of the acoustic signal typical of the onset of compressor surge. The primary goal of this acoustic analysis was to establish an online methodology to monitor compressor stability that can be anticipated and avoided.

Sign in / Sign up

Export Citation Format

Share Document