Annular Diffuser Performance for an Automotive Gas Turbine

1979 ◽  
Vol 101 (3) ◽  
pp. 358-372 ◽  
Author(s):  
D. Japikse ◽  
R. Pampreen
Keyword(s):  
Gas Turbine ◽  
Model Test ◽  
Experimental Tests ◽  
Swirl Flow ◽  
Operating Conditions ◽  
Annular Diffuser ◽  
Test Pressure ◽  
Inlet Swirl ◽  
Inlet Conditions ◽  
Computational Analyses

A series of experimental tests and computational analyses are reported for two automotive gas turbine diffusers. The diffusers include an interstage and an exhaust diffuser plus collector. The diffuser models were tested at Reynolds numbers and inlet blockage levels characteristic of the engine operating conditions. A rig test of the interstage diffuser is also reported. Inlet swirl and Mach number were systematically varied in the model tests. Good recovery was found for each diffuser at zero swirl. Recovery degraded at high swirl for the interstage diffuser. The exhaust diffuser with a double discharge collector showed little sensitivity to inlet swirl. Flow visualization indicates that the interstage diffuser was separated at modest swirl levels, at least in the model test. Pressure recovery in the rig (with upstream rotor and downstream stator) was found to be greater than in the model test (using “clean” inlet conditions). Comparisons between measured wall pressures and calculations provide further basic insights.

Calibration of Gas Turbine Blade Temperature Predictions Using Surrogate Models

2012 ◽  
Author(s):  
John M. McFarland ◽  
Grant O. Musgrove ◽  
Sung Yong Chang ◽  
David L. Ransom
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Analyses ◽  
Surrogate Models ◽  
Operating Conditions ◽  
Test Bed ◽  
Turbine Inlet ◽  
Speed Up ◽  
Inlet Conditions ◽  
Thickness Measurements

Actual gas turbine performance and component life at specific engine installations is highly dependent on the actual operating conditions, since not all engines are operated in the same manner. Due to the variability in turbine operation, it may be prudent to evaluate the operation of hot section components for turbine inlet conditions that are specific to a single installation. However, determining the actual turbine inlet conditions can be a difficult and expensive process that is usually only done on test bed gas turbines. This paper presents a method to determine turbine inlet conditions using a model calibration approach. Two-stage CFD and thermal analyses are developed to predict blade temperature. By varying the model inputs, computational predictions of blade temperature are calibrated to blade interdiffusion zone thickness measurements. In order to speed up calculations, surrogate models are used in place of the full-scale analysis codes during the calibration analysis. The result of the study is a prediction of the turbine inlet profile necessary to obtain the best agreement between predicted and measured blade temperatures.

A Sensitivity Study of Gas Turbine Exhaust Diffuser-Collector Performance at Various Inlet Swirl Angles and Strut Stagger Angles

2017 ◽  
Author(s):  
Michal P. Siorek ◽  
Stephen Guillot ◽  
Song Xue ◽  
Wing F. Ng
Keyword(s):  
Gas Turbine ◽  
Flow Direction ◽  
Flow Behavior ◽  
Exhaust System ◽  
Sensitivity Study ◽  
Inlet Swirl ◽  
Inlet Conditions ◽  
Gas Turbine Exhaust ◽  
The Impact ◽  
Turbine Exhaust

This paper describes studies completed using a quarter-scaled rig to assess the impact of turbine exit swirl angle and strut stagger on a turbine exhaust system consisting of an integral diffuser-collector. Advanced testing methods were applied to ascertain exhaust performance for a range of inlet conditions aerodynamically matched to flow exiting an industrial gas turbine. Flow visualization techniques along with complementary Computational Fluid Dynamics (CFD) predictions were used to study flow behavior along the diffuser endwalls. Complimentary CFD analysis was also completed with the aim to ascertain the performance prediction capability of modern day analytical tools for design phase and off-design analysis. The K-Epsilon model adequately captured the relevant flow features within both the diffuser and collector, and the model accurately predicted the recovery at design conditions. At off-design conditions, the recovery predictions were found to be pessimistic. The integral diffuser-collector exhaust accommodated a significant amount of inlet swirl without a degradation in performance, so long as the inlet flow direction did not significantly deviate from the strut stagger angle. Strut incidence at the hub was directly correlated with reduction in overall performance, whereas the diffuser-collector performance was not significantly impacted by strut incidence at the shroud.

A Sensitivity Study of Gas Turbine Exhaust Diffuser-Collector Performance at Various Inlet Swirl Angles and Strut Stagger Angles

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Michal P. Siorek ◽  
Stephen Guillot ◽  
Song Xue ◽  
Wing F. Ng
Keyword(s):  
Gas Turbine ◽  
Flow Direction ◽  
Flow Behavior ◽  
Exhaust System ◽  
Sensitivity Study ◽  
Inlet Swirl ◽  
Inlet Conditions ◽  
Gas Turbine Exhaust ◽  
The Impact ◽  
Turbine Exhaust

This paper describes studies completed using a quarter-scaled rig to assess the impact of turbine exit swirl angle and strut stagger on a turbine exhaust system consisting of an integral diffuser-collector. Advanced testing methods were applied to ascertain exhaust performance for a range of inlet conditions aerodynamically matched to flow exiting an industrial gas turbine. Flow visualization techniques along with complementary computational fluid dynamics (CFD) predictions were used to study flow behavior along the diffuser end walls. Complimentary CFD analysis was also completed with the aim to ascertain the performance prediction capability of modern day analytical tools for design phase and off-design analysis. The K-Epsilon model adequately captured the relevant flow features within both the diffuser and collector, and the model accurately predicted the recovery at design conditions. At off-design conditions, the recovery predictions were found to be pessimistic. The integral diffuser-collector exhaust accommodated a significant amount of inlet swirl without degradation in performance, so long as the inlet flow direction did not significantly deviate from the strut stagger angle. Strut incidence at the hub was directly correlated with reduction in overall performance, whereas the diffuser-collector performance was not significantly impacted by strut incidence at the shroud.

Technical Basis for Acceptance/Rejection Criteria for Flaws in High Pressure Gas Cylinder

2009 ◽  
Author(s):  
Mahendra D. Rana ◽  
John H. Smith ◽  
Henry Holroyd
Keyword(s):  
High Pressure ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Flaw Size ◽  
Critical Flaw ◽  
Test Pressure ◽  
Technical Basis

The objective of this paper is to present the technical basis used for developing acceptance/rejection limits for seamless, high pressure gas cylinders that can be used at the time of retesting the cylinders. The development of acceptance/rejection limits for cylinders is done in three steps. First, the “critical flaw sizes” (e.g. depth and length or area) for selected types of flaws are established by an analysis procedure that has been verified by experimental tests. Next the “allowable flaw sizes” are calculated by modifying (reducing) the size of the “critical flaw sizes” for each cylinder by adjusting for fatigue crack growth that may occur during the use of the cylinder. Finally the “acceptance/rejection criteria” is established to take into account other factors such as all the expected operating conditions that the cylinders may see in service and the reliability and detectability of the specific inspection equipment to be and to adjust the “allowable flaw sizes” to provide an additional margin of safety. This acceptance/rejection limits have been incorporated in recently published ISO Technical Report TR 22694: 2008 [1]. In this work, the API 579 “Recommended Practice for Fitness-for-Service” [2] was used to calculate the “critical flaw sizes” for a range of cylinder sizes and strength levels. For this study the “critical flaw size” is defined as the size of the flaw that will cause the cylinders to fail at the test pressure of the cylinder. The results of flawed-cylinder burst tests were used to experimentally verify the calculated “critical flaw sizes”. The “allowable flaw sizes” were then calculated by using well established fatigue crack growth rate data for steel and aluminum alloys to allow for the expected amount of fatigue crack growth that may occur during the specified retesting intervals. A limited number of tests were conducted to verify the “allowable flaw size” calculations. Further adjustments are made to the “allowable flaw sizes” to define the “acceptance/rejection criteria” to be used during cylinder retesting.

Analysis of Time-Wise Compressor Fouling Phenomenon on a Multistage Test Compressor: Performance Losses and Particle Adhesion

2020 ◽  
Author(s):  
Alessandro Vulpio ◽  
Alessio Suman ◽  
Nicola Casari ◽  
Michele Pinelli ◽  
Rainer Kurz ◽  
...  
Keyword(s):  
Pressure Ratio ◽  
Particle Diameter ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Capture Efficiency ◽  
Compressor Unit ◽  
Compressor Performance ◽  
Multistage Compressor ◽  
Inlet Conditions ◽  
Over Time

Abstract The analysis of the performance losses of a multistage compressor concerning the air contaminant is not widespread in literature and, the mutual interactions of particle materials, air humidity, and compressor load are not well studied. The airborne micrometric particles that enter the compressor can deposit on the internal surfaces, causing the loss of performance of the machine. In this paper, several experimental tests have been carried out on a multistage compressor unit. A detailed analysis has been carried out considering soil and soot ingestion, as well as the air relative humidity (ranging from 50 %RH to 80 %RH) and compressor rotating velocity. Several combinations of particle diameter, material, and operating conditions have been considered. The amount of contaminant at the compressor outlet has been measured and the capture efficiency of the whole machine has been determined. Over the exposure time, the capture efficiency ranges from 0.2 to 0.6 according to the powder type and compressor inlet conditions. The capability of the compressor to collect particles changes over time as a function of the condition, even if, several tested cases appear characterized by an almost constant capture efficiency trend. In addition, the performance degradation has been monitored over time and, with the reference of the particle concentration, the present experimental campaign covers about 500 operating hours of an actual installation. After a detailed evaluation of experimental uncertainty, the performance losses due to particle contamination has been assessed. The losses in the compressor performance have been estimated by means of the pressure ratio of the axial stages. The maximum degradation has been estimated equal to 0.53 % per hour for the compressor pressure ratio. Soot particles appear stickier, especially in the presence of higher humidity and represent the most detrimental operating conditions for the compressor unit.

scholarly journals Effect of swirl flow on the performance of parallel hub axial annular diffuser

2021 ◽  
Author(s):  
Hardial Singh ◽  
◽  
Arora B.B ◽  
Keyword(s):  
Swirling Flow ◽  
Cone Angle ◽  
Axial Flow ◽  
Swirl Flow ◽  
Recovery Coefficient ◽  
Pressure Loss Coefficient ◽  
Swirl Angle ◽  
Annular Diffuser ◽  
Inlet Swirl ◽  
Result Analysis

In the present work, the parallel hub axial flow annular diffuser's performance characteristics with divergent casing varying between equivalent cone angle (10°, 15°, and 20°) with area ratio 3 have been evaluated computationally as well as experimentally. The performance of three diffusers were tested at different inlet swirl angles (from 0° to 25°) for swirling and non-swirling flow. Simulations have been carried out on a fully developed flow at Reynolds number 2.5×105. The results were analyzed based on the velocity profiles, static pressure recovery coefficient, and the total pressure loss coefficient. The result analysis shows that the inlet swirl flow improves the recovery of pressure and also delays the flow separation on the casing. Moreover,the findings also show that the best performance was achieved in equivalent cone angle 10° at the inlet swirl angle of 7.5° compared to other diffusers.

Analysis of Time-Wise Compressor Fouling Phenomenon On a Multistage Test Compressor: Performance Losses and Particle Adhesion

2021 ◽  
Author(s):  
Alessandro Vulpio ◽  
Alessio Suman ◽  
Nicola Casari ◽  
Michele Pinelli ◽  
Rainer Kurz ◽  
...  
Keyword(s):  
Pressure Ratio ◽  
Particle Diameter ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Capture Efficiency ◽  
Compressor Unit ◽  
Compressor Performance ◽  
Inlet Conditions ◽  
Powder Type ◽  
Over Time

Abstract In this paper, several experimental tests have been carried out on a multistage compressor unit. A detailed analysis has been carried out considering soil and soot ingestion, as well as the air relative humidity (ranging from 50 %RH to 80 %RH) and compressor rotating velocity. Several combinations of particle diameter, material, and operating conditions have been considered. The amount of contaminant at the compressor outlet has been measured and the capture efficiency of the whole machine has been determined. Over the exposure time, the capture efficiency ranges from 0.2 to 0.6 according to the powder type and compressor inlet conditions. The capability of the compressor to collect particles changes over time as a function of the condition, even if, several tested cases appear characterized by an almost constant capture efficiency trend. In addition, the performance degradation has been monitored over time and, with the reference of the particle concentration, the present experimental campaign covers about 500 operating hours of an actual installation. After a detailed evaluation of experimental uncertainty, the performance losses due to particle contamination has been assessed. The losses in the compressor performance have been estimated by means of the pressure ratio of the axial stages. The maximum degradation has been estimated equal to 0.53 % per hour for the compressor pressure ratio. Soot particles appear stickier, especially in the presence of higher humidity and represent the most detrimental operating conditions for the compressor unit.

Open-Loop Active Control of Combustion Dynamics on a Gas Turbine Engine

2004 ◽  
Author(s):  
Geo. A. Richards ◽  
Jimmy D. Thornton ◽  
Edward H. Robey ◽  
Leonell Arellano
Keyword(s):  
Gas Turbine ◽  
Active Control ◽  
Closed Loop ◽  
Experimental Tests ◽  
Gas Turbine Engine ◽  
Open Loop ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Combustion Dynamics ◽  
Turbine Engine

Combustion dynamics is a prominent problem in the design and operation of low-emission gas turbine engines. Even modest changes in fuel composition, or operating conditions can lead to damaging vibrations in a combustor that was otherwise stable. For this reason, active control has been sought to stabilize combustors that must accommodate fuel variability, new operating conditions, etc. Active control of combustion dynamics has been demonstrated in a number of laboratories, single-nozzle test combustors, and even on a fielded engine. In most of these tests, active control was implemented with closed-loop feedback between the observed pressure signal and the phase and gain of imposed fuel perturbations. In contrast, a number of recent papers have shown that open-loop fuel perturbations can disrupt the feedback between acoustics and heat release that drives the oscillation. Compared to the closed-loop case, this approach has some advantages because it may not require high-fidelity fuel actuators, and could be easier to implement. This paper reports experimental tests of open-loop fuel perturbations to control combustion dynamics in a complete gas turbine engine. Results demonstrate the technique was very successful on the test engine, and had minimal effect on pollutant emissions.

CFD Study of a Micro-Combustor Under Variable Operating Conditions

2017 ◽  
Author(s):  
Maria Cristina Cameretti ◽  
Roberta De Robbio ◽  
Raffaele Tuccillo
Keyword(s):  
Gas Turbine ◽  
Fossil Fuels ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Combustion Model ◽  
Low Carbon ◽  
Kinetic Mechanisms ◽  
Micro Turbine ◽  
Set Up

New concepts for power generation are discussed as a response to CO2 emissions from the combustion of fossil fuels. These concepts include low-carbon fuels as well as new fuel supplies will be used, with (biogenic) low-caloric gases such as syngas with an amount of hydrogen, with a share of 50% and even higher. However, hydrogen mixtures have a higher reactivity than natural gas (NG) mixtures, burned mostly in today’s gas turbine combustors. The authors discuss in this paper the potential of a micro gas turbine (MGT) combustor when operated under unconventional conditions, both in terms of variation in the fuel supplied and concerning the part-load or off-design operation. In particular, the authors’ methodology relies on an advanced CFD approach that makes use of extended kinetic mechanisms coupled with the turbulent interaction of the reacting species. A preliminary set-up of the combustion model is based on data provided by experimental tests of the micro-turbine. In the paper, several computational examples are discussed, namely: - The comparison of combustion stability and efficiency and pollutant production with several fuels. - The analysis of the combustor response with reduced load. - The use of the pilot and main injectors for supplying different fuels.

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