Improved criteria for stall-free preliminary design of axial compressor of aero gas turbine engines

2018 ◽  
Vol 233 (9) ◽  
pp. 3286-3297 ◽  
Author(s):  
MR Aligoodarz ◽  
A Mehrpanahi ◽  
M Moshtaghzadeh ◽  
A Hashiehbaf
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Axial Compressor ◽  
Axial Flow ◽  
Design Criterion ◽  
Flow Coefficient ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Parameter Ranges ◽  
Axial Flow Compressors

A worldwide effort has been devoted to developing highly efficient and reliable gas turbine engines. There exist many prominent factors in the development of these engines. One of the most important features of the optimal design of axial flow compressors is satisfying the allowable range for various parameters such as flow coefficient, stage loading, the degree of reaction, De-Haller number, etc. But, there are some applicable cases that the mentioned criteria are exceeded. One of the most famous parameters is De-Haller number, which according to literature data should not be kept less than 0.72 in any stage of the axial compressor. A deep insight into the current small- or large-scale axial flow compressors shows that a discrepancy will occur among design criterion for De-Haller number and experimental measurements in which the De-Haller number is less than the design limit but no stall or surge is observed. In this paper, an improved formulation is derived based on one-dimensional modeling for predicting the stall-free design parameter ranges especially stage loading, flow coefficient, etc. for various combinations. It was found that the current criterion is much more accurate than the De-Haller criterion for design purposes.

scholarly journals Development and Applications of a Stage Stacking Procedure

2012 ◽  
Author(s):  
Sameer Kulkarni ◽  
Mark L. Celestina ◽  
John J. Adamczyk
Keyword(s):  
Gas Turbine ◽  
Axial Compressor ◽  
Sensitivity Study ◽  
Flow Coefficient ◽  
Turbine Engines ◽  
Stable Operation ◽  
Gas Turbine Engines ◽  
Axial Compressors ◽  
Design Performance ◽  
Load Following

The preliminary design of multistage axial compressors in gas turbine engines is typically accomplished with mean-line methods. These methods, which rely on empirical correlations, estimate compressor performance well near the design point, but may become less reliable off-design. For land-based applications of gas turbine engines, off-design performance estimates are becoming increasingly important, as turbine plant operators desire peaking or load-following capabilities and hot-day operability. The current work develops a one-dimensional stage stacking procedure. This includes a newly-defined blockage term, which is used to estimate the off-design performance and operability range of a 13-stage axial compressor. The new blockage term is defined to give mathematical closure on static pressure, and values of blockage are shown to collapse to a curve as functions of stage inlet flow coefficient and corrected speed. Utility of the stage stacking procedure is demonstrated by estimation of the minimum corrected speed which allows stable operation of the compressor. Further utility of the stage stacking procedure is demonstrated with a bleed sensitivity study, which estimates a bleed schedule to expand the compressor’s operating range.

scholarly journals EFFECT OF HYSTERESIS IN AXIAL COMPRESSORS OF GAS-TURBINE ENGINES

Aviation ◽  
2012 ◽  
Vol 16 (4) ◽  
pp. 97-102 ◽  
Author(s):  
Mykola Kulyk ◽  
Ivan Lastivka ◽  
Yuri Tereshchenko
Keyword(s):  
Gas Turbine ◽  
Axial Compressor ◽  
Separated Flow ◽  
Aerodynamic Performance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Bladed Disks ◽  
Axial Compressors

The phenomenon of separated flow hysteresis in the process of the streamlining the axial compressor of gas-turbine engines is considered. Generalised results of research on the occurrence of hysteresis in the aerodynamic performance of compressor grids and its influence on the performance of the bladed disks of compressors that operate in real conditions of periodic circular non-uniformity are demonstrated.

A Mean Line Prediction Method for Axial Flow Turbine Efficiency

1982 ◽  
Vol 104 (1) ◽  
pp. 111-119 ◽  
Author(s):  
S. C. Kacker ◽  
U. Okapuu
Keyword(s):  
Gas Turbine ◽  
Axial Flow ◽  
Prediction Method ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Loss System ◽  
Turbine Efficiency ◽  
Wide Range ◽  
Line Loss ◽  
Axial Turbines

A mean line loss system is described, capable of predicting the design point efficiencies of current axial turbines of gas turbine engines. This loss system is a development of the Ainley/Mathieson technique of 1951. The prediction method is tested against the “Smith’s chart” and against the known efficiencies of 33 turbines of recent design. It is shown to be able to predict the efficiencies of a wide range of axial turbines of conventional stage loadings to within ± 1 1/2 percent.

Component Integration and Loss Sources in 3 – 5 kW Gas Turbines

2005 ◽  
Author(s):  
M. A. Monroe ◽  
A. H. Epstein ◽  
H. Kumakura ◽  
K. Isomura
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Large Scale ◽  
Engine Performance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Flow Distortion ◽  
Thermal Isolation ◽  
Component Integration ◽  
Measured Efficiency

The performance of a regenerated gas turbine generator in the 3–5 kW power range has been analyzed to understand why its measured efficiency was on the order of 6% rather than the 20% suggested by consideration of its components’ efficiencies as measured on rigs. This research suggests that this discrepancy can be primarily attributed to heat and fluid leaks not normally considered in the analysis of large gas turbine engines because they are not as important at large scale. In particular, fluid leaks among the components and heat leakage from the hot section into the compressor flow path contributed the largest debits to the engine performance. Such factors can become more important as the engine size is reduced. Other non-ideal effects reducing engine performance include temperature flow distortion at the entrance to both the compressor and turbine. A cycle calculation including all of the above effects matched measured engine data. It suggests that relatively simple changes such as thermal isolation and leak sealing can increase both power output and efficiency of this engine, over 225% in the latter case. The validity of this analysis was demonstrated on an engine in which partial thermal isolation and improved sealing resulted in a more than 40% increase in engine output power.

Predicting the Ultimate Performance of Advanced Power Cycles Based on Very High Temperature Gas Turbine Engines

1993 ◽  
Author(s):  
Paolo Chiesa ◽  
Stefano Consonni ◽  
Giovanni Lozza ◽  
Ennio Macchi
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Computer Code ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Temperature ◽  
Clear Trend ◽  
Performance Improvements ◽  
Future Technology ◽  
The Impact

It is well known that the history of gas turbine engines has been characterized by a very clear trend toward higher and higher operating temperatures, a growth which in the past 40 years has progressed at the impressive pace of approximately 13°C/year. Expected improvements in blade cooling techniques and advancements in materials indicate that this tendency is going to last for long time, leading to firing temperatures of over 1500°C within the next two decades. This paper investigates the impact of such temperature increase on optimal cycle arrangements and on ultimate performance improvements achievable by future advanced gas/steam cycles for large-scale power generation. Performance predictions have been carried out by a modified, improved version of a computer code originally devised and calibrated for “1990 state-of-the-art” gas/steam cycles. The range of performances to be expected in the next decades has been delimited by considering various scenarios of cooling technology and materials, including the extreme situations of adiabatic expansion and stoichiometric combustion. The results of parametric thermodynamic analyses of several cycle configurations are presented for a number of technological scenarios, including cycles with intercooling and reheat. A specific section discusses how the optimum configuration of the bottoming steam cycle changes to keep up with exhaust gas temperature increases. Calculations show that, under plausible assumptions on future technology advancements, within two decades the proper selection of plant configuration and operating parameters can yield net efficiencies of over 60%.

High Power Density Silicon Combustion Systems for Micro Gas Turbine Engines

2003 ◽  
Vol 125 (3) ◽  
pp. 709-719 ◽  
Author(s):  
C. M. Spadaccini ◽  
A. Mehra ◽  
J. Lee ◽  
X. Zhang ◽  
S. Lukachko ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Experimental Testing ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Deep Reactive Ion Etching ◽  
Turbine Engine ◽  
Micro Gas Turbine ◽  
Power Densities ◽  
Important Design

As part of an effort to develop a microscale gas turbine engine for power generation and micropropulsion applications, this paper presents the design, fabrication, experimental testing, and modeling of the combustion system. Two radial inflow combustor designs were examined; a single-zone arrangement and a primary and dilution-zone configuration. Both combustors were micromachined from silicon using deep reactive ion etching (DRIE) and aligned fusion wafer bonding. Hydrogen-air and hydrocarbon-air combustion were stabilized in both devices, each with chamber volumes of 191mm3. Exit gas temperatures as high as 1800 K and power densities in excess of 1100MW/m3 were achieved. For the same equivalence ratio and overall efficiency, the dual-zone combustor reached power densities nearly double that of the single-zone design. Because diagnostics in microscale devices are often highly intrusive, numerical simulations were used to gain insight into the fluid and combustion physics. Unlike large-scale combustors, the performance of the microcombustors was found to be more severely limited by heat transfer and chemical kinetics constraints. Important design trades are identified and recommendations for microcombustor design are presented.

Effects of Periodic Inflow Unsteadiness on the Time-Averaged Velocity Field and Pressure Recovery of a Diffusing Bend With Strong Curvature

2004 ◽  
Vol 126 (2) ◽  
pp. 229-237 ◽  
Author(s):  
M. I. Yaras ◽  
P. Orsi
Keyword(s):  
Velocity Field ◽  
Gas Turbine ◽  
Large Scale ◽  
Cross Flow ◽  
Operating Conditions ◽  
Pressure Recovery ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Cross Sectional ◽  
Data Set

This study examines the effects of periodic inflow unsteadiness on the flow development through fishtail-shaped diffusers utilized on small gas-turbine engines. In this application, periodic unsteadiness is caused by a jet-wake type of flow discharging from each passage of the centrifugal compressor impeller. The study consists of detailed measurements in a large-scale fishtail diffuser rig with a geometry that is typical of those used in small gas-turbine engines. Measurements of the transient velocity field have been performed at five cross-sectional planes throughout the diffuser using a miniature hot-wire probe with four wires. These measurements involve frequencies of inflow unsteadiness corresponding to design as well as off-design operating conditions. Results indicate significant effects of inflow unsteadiness at the low end of the tested frequencies on the time-averaged streamwise and cross-flow velocity fields in the diffuser. This is shown to translate into a notable impact on the pressure recovery. In addition to providing insight into the physics of this flow, the experimental results presented here constitute a detailed and accurate data set that can be used to validate computational-fluid-dynamics algorithms for this type of flow.

scholarly journals Design of Multi-Stage Axial Flow Compressor and Validation using Numerical Simulations

2019 ◽  
Vol 9 (2) ◽  
pp. 2320-2325
Keyword(s):  
Axial Compressor ◽  
Axial Flow ◽  
Thermodynamic Calculations ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Multi Stage ◽  
Velocity Triangle ◽  
And Performance ◽  
Flow Compressor ◽  
The Impact

The optimum yield of gas turbine engines has so far been driven on and around the operational efficiency of the compressor and in essence around the efficiency of the compressor blade. The efficacy of a compressor is ascertained substantially by the smoothness of the air flowing through it. In this present work, a multi-stage axial compressor in the Turbojet engine with an application for propulsion is designed based on thermodynamic calculations. The calculations were carried out employing the principles of thermodynamics, and aerodynamics along the mean streamline based on the technique of a velocity triangle in the lack of inlet guide vanes. The coordinates for the blade profile has been calculated on and around the premise of the calibrated blade base profile. The model for the seven-stage axial flow compressors based on thermodynamic calculations was devised and analyzed utilizing computational fluid dynamics methodology. The multiple reference frame approach was used to represent the impact of both rotating and stationary components and the simulation for the first stage was conducted using a periodic approach. For the intent of the verification, a comparison was made between the analytical values and the simulated values and the variation between these values was found to be 16.7%. Validation results demonstrate that the proposed method is valid and can be used for multi-stage axial compressor design and performance evaluation.

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