Single-Stage Axial Compressor Component Development for Small Gas Turbines. Volume 3. Supersonic Compressor Stage Development

1969 ◽  
Author(s):  
Charles H. Muller ◽  
Leslie R. Cox
Keyword(s):  
Gas Turbines ◽  
Axial Compressor ◽  
Single Stage ◽  
Compressor Stage ◽  
Component Development ◽  
Stage Development

Experimental Investigation of the Steady and Unsteady Flow Field in a Single Stage Low Pressure Axial Compressor With a Circumferential Groove Casing Treatment

2010 ◽  
Author(s):  
N. Van de Wyer ◽  
B. Farkas ◽  
J. Desset ◽  
J. F. Brouckaert ◽  
J.-F. Thomas ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Unsteady Flow ◽  
Axial Compressor ◽  
Low Pressure ◽  
Fast Response ◽  
Single Stage ◽  
Compressor Stage ◽  
Casing Treatment ◽  
Circumferential Groove

This paper deals with the experimental investigation of the influence of a circumferential groove casing treatment on the performance and stability margin of a single stage low pressure axial compressor. The design of the compressor stage is representative of a booster stage for the new counter-rotating turbofan engine architecture and is characterized by unusually high loading and flow coefficients. The choice of the circumferential groove is described on the basis of a numerical parametric study on the number of grooves, the axial position, the depth and width of the groove. The experiments were performed at a Reynolds number corresponding to cruise conditions in the von Karman Institute closed loop high speed compressor test rig R4. The detailed performance characterization of the compressor stage with casing treatment was mapped at four operating points from choke to stall at design speed. The compressor stall limit was determined at several other off-design speeds. Detailed steady and unsteady measurements were performed to determine the flow field characteristics of the rotor and of the complete stage. Conventional pressure, temperature and directional probes were used along with fast response pressure sensors in the rotor casing and in the groove. Simultaneous traverses with a fast response total pressure probe were used to map the unsteady flow field at the rotor exit allowing an experimental capture of the tip leakage vortex path and extension through the rotor passage. A comparison of the flow features with and without casing treatment was performed and the results are discussed against 3D viscous computational predictions. The casing treatment did not present any improvement of the compressor stall margin but no significant performance degradation was observed either. The CFD predictions showed a good agreement with the measurements and their analysis supported the experimental results.

Compressor Fouling Modeling: Relationship Between Computational Roughness and Gas Turbine Operation Time

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Francesco Melino ◽  
Mirko Morini ◽  
Antonio Peretto ◽  
Michele Pinelli ◽  
Pier Ruggero Spina
Keyword(s):  
Fluid Dynamics ◽  
Surface Roughness ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Axial Compressor ◽  
Operation Time ◽  
Compressor Stage ◽  
Performance Map ◽  
Computational Fluid Dynamics Cfd ◽  
Compressor Performance

Gas turbine axial compressor performance is heavily influenced by blade fouling. As a result, the gas turbines efficiency and producible power output decrease. Performance degradation of an axial compressor stage due to fouling can be analyzed by means of simulation through computational fluid dynamics (CFD) codes. Usually these methods reproduce the deteriorated blades by increasing their surface roughness and thickness. Another approach is the scaling of compressor stage performance maps. A model based on stage-by-stage techniques was presented in a previous work. This model is able to estimate the modifications of the overall compressor performance map as a function of the operating hours. The aim of the present study is to combine these two different approaches in order to relate the increase of blade computational surface roughness with compressor operating hours.

Compressor Fouling Modeling: Relationship Between Computational Roughness and Gas Turbine Operation Time

2011 ◽  
Author(s):  
Francesco Melino ◽  
Mirko Morini ◽  
Antonio Peretto ◽  
Michele Pinelli ◽  
Pier Ruggero Spina
Keyword(s):  
Fluid Dynamics ◽  
Surface Roughness ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Axial Compressor ◽  
Operation Time ◽  
Compressor Stage ◽  
Performance Map ◽  
Computational Fluid Dynamics Cfd ◽  
Compressor Performance

Gas turbine axial compressor performance is heavily influenced by blade fouling; as a result, the gas turbines efficiency and producible power output decrease. Performance degradation of an axial compressor stage due to fouling can be analyzed by means of simulation through Computational Fluid Dynamics (CFD) codes. Usually these methods reproduce the deteriorated blades by increasing their surface roughness and/or thickness [1]. Another approach is the scaling of compressor stage performance maps. A model based on stage-by-stage techniques was presented in a previous work. This model is able to estimate the modifications of the overall compressor performance map as a function of the operating hours [2]. The aim of the present study is to combine these two different approaches in order to relate the increase of blade computational surface roughness with compressor operating hours.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

Studies on Downstream Stator With Rotor Re-Staggering and Forward Sweeping in a Subsonic Axial Compressor Stage

2011 ◽  
Author(s):  
P. V. Ramakrishna ◽  
M. Govardhan
Keyword(s):  
Flow Field ◽  
Computational Model ◽  
Flow Rate ◽  
Total Pressure ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Axial Distance ◽  
Compressor Stage ◽  
Numerical Work ◽  
Stagger Angle

The present numerical work studies the flow field in subsonic axial compressor stator passages for: (a) preceding rotor sweep (b) preceding rotor re-staggering (three stagger angle changes: 0°, +3° and +5°); and (c) stator sweeping (two 20° forward sweep schemes). The following are the motives for the study: at the off-design conditions, compressor rotors are re-staggered to alleviate the stage mismatching by adjusting the rows to the operating flow incidence. Fundamental to this is the understanding of the effects of rotor re-staggering on the downstream component. Secondly, sweeping the rotor stages alters the axial distance between the successive rotor-stator stages and necessitates that the stator vanes must also be swept. To the best of the author’s knowledge, stator sweeping to suit such scenarios has not been reported. The computational model for the study utilizes well resolved hexahedral grids. A commercial CFD package ANSYS® CFX 11.0 was used with standard k-ω turbulence model for the simulations. CFD results were well validated with experiments. The following observations were made: (1) When the rotor passage is closed by re-staggering, with the same mass flow rate and the same stator passage area, stators were subjected to negative incidences. (2) Effect of stator sweeping on the upstream rotor flow field is insignificant. Comparison of total pressure rise carried by the downstream stators suggests that an appropriate redesign of stator is essential to match with the swept rotors. (3) While sweeping the stator is not recommended, axial sweeping is preferable over true sweeping when it is necessary.

Comparison of Transient Modeling Techniques for a Micro Turbine Engine

2006 ◽  
Author(s):  
Craig R. Davison ◽  
A. M. Birk
Keyword(s):  
Gas Turbines ◽  
Relative Size ◽  
Rate Of Change ◽  
Single Stage ◽  
Radial Compression ◽  
Shaft Speed ◽  
Transient Effects ◽  
Rates Of Change ◽  
Experimental Apparatus ◽  
Transient Modeling

A large number of papers have been published on transient modeling of large industrial and military gas turbines. Few, however, have examined micro turbines. The decrease in size affects the relative rates of change of shaft speed, gas dynamics and heat soak. This paper compares the modeled transient effects of a micro turbojet engine comprised of a single stage of radial compression and a single stage of axial expansion, with a diameter of 12cm. The model was validated with experimental data. Several forms of the model were produced starting with the shaft and fuel transients. Conservation of mass, and then energy, was subsequently added for the compressor, combustor and turbine, and a large inlet plenum that was part of the experimental apparatus. Heat soak to the engine body was incorporated into both the shaft and energy models. Heat soak was considered in the compressor, combustor and turbine. Since the engine diameter appears in the differential equations to different powers, the relative rates of change vary with diameter. The rate of change of shaft speed is very strongly influenced. The responses of the different transient effects are compared. The relative solution times are also discussed, since the relative size of the required time steps changes when compared to a large engine.

Stall Warning Using the Rotor Tip Pressure in a Transonic Axial Compressor With Circumferential Grooves

2018 ◽  
Author(s):  
Byeung Jun Lim ◽  
Tae Choon Park ◽  
Young Seok Kang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Single Stage ◽  
Stall Inception ◽  
Casing Treatment ◽  
Stall Warning ◽  
Transonic Axial Compressor

In this study, characteristics of stall inception in a single-stage transonic axial compressor with circumferential grooves casing treatment were investigated experimentally. Additionally, the characteristic of increasing irregularity in the pressure inside circumferential grooves as the compressor approaches the stall limit was applied to the stall warning method. Spike-type rotating stall was observed in the single-stage transonic axial compressor with smooth casing. When circumferential grooves were applied, the stall inception was suppressed and the operating point of the compressor moved to lower flow rate than the stall limit. A spike-like disturbance was developed into a rotating stall cell and then the Helmholtz perturbation was overlapped on it at N = 80%. At N = 70 %, the Helmholtz perturbation was observed first and the amplitude of the wave gradually increased as mass flow rate decreased. At N = 60%, spike type stall inceptions were observed intermittently and then developed into continuous rotating stall at lower mass flow rate. Pressure measured at the bottom of circumferential grooves showed that the level of irregularity of pressure increased as flow rate decreased. Based on the characteristic of increasing irregularity of the pressure signals inside the circumferential grooves as stall approaches, an autocorrelation technique was applied to the stall warning. This technique could be used to provide warning against stall and estimate real-time stall margins in compressors with casing treatments.

Numerical Efforts of Aerodynamic Re-Design in a Single-Stage Transonic Axial Compressor: Part 1 — Stator Design

2017 ◽  
Author(s):  
Justin (Jongsik) Oh
Keyword(s):  
Pressure Ratio ◽  
Axial Compressor ◽  
Axial Flow ◽  
Single Stage ◽  
Design Flow ◽  
Design Parameters ◽  
Original Design ◽  
Circular Arc ◽  
Surge Margin ◽  
Flow Compressor

In many aerodynamic design parameters for the axial-flow compressor, three variables of tailored blading, blade lean and sweep were considered in the re-design efforts of a transonic single stage which had been designed in 1960’s NASA public domains. As Part 1, the re-design was limited to the stator vane only. For the original MCA (Multiple Circular Arc) blading, which had been applied at all radii, the CDA (Controlled Diffusion Airfoil) blading was introduced at midspan as the first variant, and the endwalls of hub and casing (or tip) were replaced with the DCA (Double Circular Arc) blading for the second variant. Aerodynamic performance was predicted through a series of CFD analysis at design speed, and the best aerodynamic improvement, in terms of pressure ratio/efficiency and operability, was found in the first variant of tailored blading. It was selected as a baseline for the next design efforts with blade lean, sweep and both combined. Among 12 variants, a case of positively and mildly leaned blades was found the most attractive one, relative to the original design, providing benefits of an 1.0% increase of pressure ratio at design flow, an 1.7% increase of efficiency at design flow, a 10.5% increase of the surge margin and a 32.3% increase of the choke margin.

Dynamic Behavior of a Solar Hybrid Gas Turbine System

2015 ◽  
Author(s):  
Christian Felsmann ◽  
Uwe Gampe ◽  
Manfred Freimark
Keyword(s):  
System Dynamics ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Power ◽  
Commercial Application ◽  
Worst Case ◽  
Electric Generator ◽  
New Findings ◽  
Component Development

Solar hybrid gas turbine technology has the potential to increase the efficiency of future solar thermal power plants by utilizing solar heat at a much higher temperature level than state of the art plants based on steam turbine cycles. In a previous paper the authors pointed out, that further development steps are required for example in the field of component development and in the investigation of the system dynamics to realize a mature technology for commercial application [1]. In this paper new findings on system dynamics are presented based on the simulation model of a solar hybrid gas turbine with parallel arrangement of the combustion chamber and solar receivers. The operational behavior of the system is described by means of two different scenarios. The System operation in a stand-alone electrical supply network is investigated in the first scenario. Here it is shown that fast load changes in the network lead to a higher shaft speed deviation of the electric generator compared to pure fossil fired systems. In the second scenario a generator load rejection, as a worst case, is analyzed. The results make clear that additional relief concepts like blow-off valves are necessary as the standard gas turbine protection does not meet the specific requirements of the solar hybrid operation. In general the results show, that the solar hybrid operational modes are much more challenging for the gas turbines control and safety system compared to pure fossil fired plants due to the increased volumetric storage capacity of the system.

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