Computational Investigation on Centrifugal Compressor Performance at Various Altitudes

2011 ◽  
Vol 230-232 ◽  
pp. 1123-1128
Author(s):  
Yu Wang ◽  
Zhen Luo
Keyword(s):  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Cfd Simulation ◽  
Numerical Solutions ◽  
Weight Ratio ◽  
Critical Factor ◽  
Computational Method ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Ambient Temperatures

Small gas turbine engines have been considered as a potential and popular mean of propulsion for Unmanned Aerial Vehicles (UAV). With the advantage of high thrust/power-to-weight-ratio from these engines, small aircraft can have larger payload allowance and higher altitude capability. However, at present, these gas turbine engines are not mature enough to perform critical mission for UAV. To be used for such critical mission, these gas turbine engines need a better reliability, efficiency and endurance. The capability of the engine to work efficiently in conditions at different altitude with the variant of air density is a critical factor related to higher operational ceiling. Hence this work aims to present a Computational Fluid Dynamics (CFD) simulation approach focusing on centrifugal compressors which are applied to turbo machines. A computational method is developed for studying the performance of small gas turbine engines over a range of altitude and ambient temperatures under different engine rates, and a centrifugal compressor simulation model is generated by using CFD techniques. Through numerical solutions obtained for different mesh sets the finest mesh of the model was determined. The performance curves obtained by the CFD simulation has been compared with the results obtained from the analytical method.

scholarly journals Application of the vacuum casting technology in the production of small-size gas turbine engine blade machines

2021 ◽  
Vol 20 (3) ◽  
pp. 152-159
Author(s):  
A. M. Faramazyan ◽  
S. S. Remchukov ◽  
I. V. Demidyuk
Keyword(s):  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Gas Turbine Engine ◽  
Shrinkage Porosity ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Vacuum Casting ◽  
Turbine Engine ◽  
Design Values ◽  
The Cost

The application of casting technologies in the production of parts and assemblies of small-size gas turbine engines is justified in the paper. The technology of vacuum casting in gypsum molds was tested during the production of an experimental centrifugal compressor of a small-size gas turbine engine. On the basis of a 3D model of the designed centrifugal compressor, computational studies of vacuum casting were carried out and rational parameters of the technological process were determined. Prototypes of the developed centrifugal compressor of a small-size gas turbine engine were made. The results of calculations and the performed technological experiment confirmed the fill rate of the gating form and the absence of short pour. The distribution of shrinkage porosity and cavities corresponds to the design values and is concentrated in the central part of the casting that is subjected to subsequent machining. The area of the blades, disc and sleeve is formed without defects. The use of casting technologies in the production of parts and assemblies of small-size gas turbine engines assures the required quality with a comparatively low price of the finished product, making it possible to achieve the balance between the cost of the technology and the quality of the product made according to this technology.

scholarly journals On the effect of the meridional contour shape on the power characteristics of a centrifugal compressor wheel

2020 ◽  
Vol 2020 (3) ◽  
pp. 12-17
Author(s):  
Yu.A. Kvasha ◽  
◽  
N.A. Zinevych ◽  
Keyword(s):  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Computational Study ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Compressor Wheel ◽  
Power Characteristics ◽  
Contour Shape ◽  
Wide Range ◽  
Uniformly Distributed Sequence

This work is concerned with the development of approaches to the optimal aerodynamic design of centrifugal compressor wheels, which is due to the use of centrifugal stages in compressors of modern aircraft gas turbine engines and power plants. The aim of this work is a computational study of the effect of the meridional contour shape of a centrifugal compressor wheel on its power characteristics. The basic method is a numerical simulation of 3D turbulent gas flows in centrifugal wheels on the basis of the complete averaged Navier¬–Stokes equations and a two-parameter turbulence model. The computational study features: varying the shape of the hub and tip part of the meridional contour over a wide range, formulating quality criteria as the mean integral values of the wheel power characteristics over the operating range of the air flow rate through the wheel, and a systematic scan of the independent variable range at points that form a uniformly distributed sequence. As a result of multiparameter calculations, it was shown that in the case of a flow without separation in the blade channels of a wheel with a given starting shape of the meridional contour, varying that shape has an insignificant effect on the wheel power characteristics. It is pointed out that in similar cases it seems to be advisable to aerodynamically improve centrifugal wheels by varying the shape of their blades in the circumferential direction rather than in the meridional plane. This conclusion was made using rather a “coarse” computational grid, which, however, retains the sensitivity of the computed results to a variation in the centrifugal wheel geometry. On the whole, this work clarifies ways of further aerodynamic improvement of centrifugal compressor impellers in cases where the starting centrifugal wheel is a well-designed wheel with a flow without separation in the blade channels. The results obtained may be used in the aerodynamic optimization of centrifugal stages of aircraft gas turbine engines.

Evaporative Cooling of Gas Turbine Engines: Climatic Analysis and Application in High Humidity Regions

2007 ◽  
Author(s):  
Mustapha Chaker ◽  
Cyrus B. Meher-Homji
Keyword(s):  
Gas Turbine ◽  
Detrimental Effect ◽  
Low Cost ◽  
Evaporative Cooling ◽  
Turbine Engines ◽  
Climatic Data ◽  
High Humidity ◽  
Gas Turbine Engines ◽  
Ambient Temperatures ◽  
Augmentation Techniques

There are numerous power generation and mechanical drive gas turbine applications where the power drop caused by high ambient temperatures has a very detrimental effect on the production of power or process throughput. Media evaporative cooling and inlet fogging are common low cost power augmentation techniques applied to reduce these losses. Several misconceptions exist regarding the applicability of evaporative cooling to what are often called “high humidity” regions. There is a sizable evaporative cooling potential in most locations when climatic data is evaluated based on an analysis of coincident wet bulb and dry bulb data. This data is not readily available to plant users and designers. This paper provides a detailed treatment of available climatic data bases and presents actual climatic data from several world wide locations to show that considerable cooling potential actually exists even in high humidity regions. It is hoped that this paper will be of value to plant designers, engineering and operating companies that are considering the use of evaporative cooling for power augmentation.

scholarly journals Thermomechanical Advances for Small Gas Turbine Engines: Present Capabilities and Future Direction in Gas Generator Designs

1988 ◽  
Author(s):  
M. Propen ◽  
H. Vogel ◽  
S. Aksoy
Keyword(s):  
Gas Turbine ◽  
Broad Spectrum ◽  
Gas Turbines ◽  
Weight Ratio ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Generator ◽  
Performance Requirements ◽  
Materials Research ◽  
Future Direction

Performance requirements of tomorrow’s gas turbines demand major improvements in specific fuel consumption and thrust to weight ratio. These stringent requirements, in turn, drive the need for higher operating temperatures and lighter weight engines. Such technical improvements impose severe thermal, structural, and metallurgical demands upon turbine components. A broad spectrum of technology programs is underway at Textron Lycoming to address these challenging requirements. This paper outlines the thermal, structural, and materials research needed for achieving the goals of the small gas turbines of tomorrow.

Optimisation Method for Multistage Compressors

2021 ◽  
pp. 38-59
Author(s):  
E.S. Goryachkin ◽  
V.N. Matveev ◽  
G.M. Popov ◽  
O.V. Baturin ◽  
Yu.D. Novikova
Keyword(s):  
Gas Turbine ◽  
Cfd Simulation ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Stability Margin ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Data Vector ◽  
Minimum Number ◽  
Multistage Compressors

The paper presents an algorithm for seeking an optimal blade configuration for multistage axial-flow compressors. The primary tool behind the algorithm is 3D CFD simulation, augmented by commercial optimisation software. The core of the algorithm involves feeding an initial data vector to the parametric simulation module so as to form a "new" blade geometry, which is then transferred to 3D computational software. The results obtained are further processed in a program that implements the algorithm for seeking the optimum and forms a new input data vector to achieve the set goal. We present a method of parametrically simulation the blade shape, implemented in a software package, making it possible to describe the shape of the compressor blade profiles using a minimum number of variables and to automatically change the shape in the optimisation cycle. The algorithm developed allows the main parameters of compressor operation (efficiency, pressure ratio, air flow rate, etc.) to be improved by correcting the profile shape and relative position of the blades. The algorithm takes into account various possible constraints. We used the method developed to solve practical problems of optimising multistage axial compressors of gas turbine engines for various purposes, with the number of compressor stages ranging from 3 to 15. As a result, the efficiency, pressure ratio and stability margin of gas turbine engines were increased

Measurements of the Effects of Periodic Inflow Unsteadiness on the Aerodynamics of a Fishtail Diffuser

2002 ◽  
Author(s):  
M. I. Yaras ◽  
P. Orsi
Keyword(s):  
Velocity Field ◽  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Data Set ◽  
Flow Measurements ◽  
Measured Velocity ◽  
Substantial Impact

This study examines the effects of periodic inflow unsteadiness on the flow development through fishtail diffusers utilized on small gas-turbine engines. The periodic unsteadiness is due to the distortion of the flow in the peripheral direction at the exit of the centrifugal compressor impeller, caused by the jet-wake type of flow discharging from each passage of the 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. An unsteady-flow generator is used to approximate the type of diffuser-inflow conditions that exist at the exit of centrifugal compressor impellers. Detailed measurements of the transient velocity field have been performed at the inlet and at four cross-sectional planes throughout the diffuser using a miniature 4-wire probe. These measurements involve frequencies of inflow unsteadiness corresponding to design as well as off-design operating conditions. The measured velocity field is analyzed in a time-averaged sense and in the context of previously-performed steady-flow measurements. Results show significant effects of inflow unsteadiness at lower frequencies on the flow field in the diffuser, which translates into a substantial impact on the pressure recovery of the diffuser. 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 codes for this application.

Carbon/Carbon Components for Advanced Gas Turbine Engines

1981 ◽  
Author(s):  
L. Danis ◽  
S. Cruzen ◽  
W. Schimmel
Keyword(s):  
Gas Turbine ◽  
Extreme Temperature ◽  
Carbon Composite ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Design Development ◽  
Turbine Wheel ◽  
Ambient Temperatures ◽  
Specific Strength ◽  
Component Design

A preliminary assessment of carbon/carbon fiber/matrix composites for extreme temperature limited life service in small gas turbine engines has been completed. Spin tests of available disks were conducted, along with structural design micromechanical analyses of tested specimens and conceptual variants. Many specific strength values at ambient temperatures were found higher than those of presently used metals. Since these values increase as temperatures are elevated, a significant advantage is provided over contemporary and advanced turbine wheel materials. A major advantage of C/C composite over monolithic ceramic is a relative absence of defect sensitivity, brittleness, or rapid fracture progression. Experiments and studies were conducted to provide carbon/carbon bodies with state-of-the-art oxidation and erosion protection. Silicon carbide coated specimens show required promising static oxidation resistance for target engine mission life. Simulated dynamic end use tests have yet to be completed. It is recommended that further programs on carbon/carbon composite turbine components be conducted immediately to address coating refinement, component design, development of appropriate fiber architecture, and characterization of those architectures which result in acceptable service properties on tested components.

One and Three-Dimensional Analysis of Centrifugal Compressor for 600 kW Simple Cycle Gas Turbine Engine

2010 ◽  
Author(s):  
Elkin I. Gutie´rrez Vela´squez ◽  
Marco A. R. Nascimento ◽  
Ruben A. Miranda Carrillo ◽  
Newton R. Moura
Keyword(s):  
Gas Turbine ◽  
Distributed Generation ◽  
Centrifugal Compressor ◽  
Economies Of Scale ◽  
Gas Turbine Engine ◽  
Simple Cycle ◽  
Computational Time ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine

Currently, industrial countries generate most of their electricity in large centralized plants. These plants have excellent economies of scale, however, they usually transmit electricity through long distances and can affect the environment. Distributed generation is another approach that reduces the amount of lost energy during transmission as the electricity is generated closely to where it is used, this way reducing the size and number of power lines to be constructed. The current technologies in DG include small gas turbine engines, internal combustion reciprocating engines, photovoltaic panels, fuel cells, solar thermal conversion and Stirling engines using fossil fuels and bio-fuels. Among them, small gas turbine engines are a promising technology for the implementation of distributed generation systems in the near future. This work presents the results of the preliminary compressor design of a simple cycle gas turbine engine, obtained with the use of a straightforward one-dimensional FORTRAN code, which enables to calculate the main characteristics of a centrifugal compressor by means of the application of non-dimensional parameters, with a vast reduction of computational time. The results obtained were compared with a CFD analysis and with experimental results taken from specialized literature; therefore a reasonable agreement was reached. The main contribution of this paper is to demonstrate that by the use of a simple code it is feasible to obtain fairly close results in comparison with those which can be obtained by laborious iterative processes such as those developed through the analysis using CFD techniques.

Thermal Tip Clearance Control for Centrifugal Compressor of an APU Engine

1994 ◽  
Vol 116 (4) ◽  
pp. 629-634 ◽  
Author(s):  
G. Eisenlohr ◽  
H. Chladek
Keyword(s):  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Qualitative Description ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Design Calculations ◽  
Clearance Control

To master today’s demand for efficiency and compactness of centrifugal compressor components for small gas turbine engines the main attention must not only be given to the aerodynamic design of the impeller and diffuser components, but also to the installation situation of the surrounding parts. A vital aspect is the tip clearance control between impeller and shroud casing over the total operating range. Using the radial compressor for a small gas turbine engine, developed at BMW Rolls-Royce, the importance of tip clearance control is demonstrated. The possibilities for influencing and optimizing passive tip clearance control by design features are described; transient expansion processes must be considered when using a thermal tip clearance control. The results of the design calculations are compared with the results on the test stand and the engine itself. An effort is made to find a qualitative influence of tip clearance to the engine power output at operating conditions. This qualitative description is substantiated by test results with different tip clearances at the compressor teststand.

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