Simulation of Premixed and Partially Premixed Jet-In-Crossflow Flames At High-Pressure

2021 ◽  
Author(s):  
Bernhard Stiehl ◽  
Michelle Otero ◽  
Tommy Genova ◽  
Tyler Worbington ◽  
Jonathan Reyes ◽  
...  
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Jet Fuel ◽  
Main Stage ◽  
Cfd Simulations ◽  
Turbine Engine ◽  
Jet In Crossflow ◽  
Flame Shape ◽  
Partially Premixed ◽  
Operating Points

Abstract In this paper we explore the operational map of a lean axial-staged combustor of premixed and partially premixed reacting jet-in-crossflow flames at high-pressure (5 atm). This study attempts to expand the data to relatively high pressure and could significantly aid scaling to real gas turbine engine conditions at 20-30 atm. High speed camera, PIV, CH* chemiluminescence, temperature and pressure measurements were taken and processed to allow accurate reconstruction of six operating points relative to CFD simulations under minimal adjustments. Variation of lean main stage (f = 0.575 and 0.73) and rich jet (f = 1.1, 4 and 8) equivalence ratio has been investigated for a four mm axial jet. The fully premixed flames were found to be controlled by the crossflow temperature before ignition and the crossflow oxygen content during combustion. Analysis of flame shape and position for the partially premixed operating points describes a lee stabilized as well as a more unsteady windward flame branch. Adjustment of added jet fuel and crossflow temperature along with its corresponding oxygen level is required to attain a compact flame body. The risk of delaying combustion progress is significantly increased at a richer jet f = 8 and an overshooting, spatially divided flame was attained with a main stage f = 0.73. Control towards a compact flame body is critical to allow combustion at reasonable reaction rate.

Simulation of Premixed and Partially Premixed Jet-in-Crossflow Flames at High-Pressure

2020 ◽  
Author(s):  
Bernhard Stiehl ◽  
Michelle Otero ◽  
Tommy Genova ◽  
Tyler Worbington ◽  
Jonathan Reyes ◽  
...  
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Jet Fuel ◽  
Main Stage ◽  
Cfd Simulations ◽  
Turbine Engine ◽  
Jet In Crossflow ◽  
Flame Shape ◽  
Partially Premixed ◽  
Operating Points

Abstract In this paper we explore the operational map of a lean axial-staged combustor of premixed and partially premixed reacting jet-in-crossflow flames at high-pressure (5 atm). This study attempts to expand the data to relatively high pressure and could significantly aid scaling to real gas turbine engine conditions at 20–30 atm. High speed camera, PIV, CH* chemiluminescence, temperature and pressure measurements were taken and processed to allow accurate reconstruction of six operating points relative to CFD simulations under minimal adjustments. Variation of lean main stage (φ = 0.575 and 0.73) and rich jet (φ = 1.1, 4 and 8) equivalence ratio has been investigated for a four mm axial jet. The fully premixed flames were found to be controlled by the crossflow temperature before ignition and the crossflow oxygen content during combustion. Analysis of flame shape and position for the partially premixed operating points describes a lee stabilized as well as a more unsteady windward flame branch. Adjustment of added jet fuel and crossflow temperature along with its corresponding oxygen level is required to attain a compact flame body. The risk of delaying combustion progress is significantly increased at a richer jet φ = 8 and an overshooting, spatially divided flame was attained with a main stage φ = 0.73. Control towards a compact flame body is critical to allow combustion at reasonable reaction rate.

scholarly journals The Design and Evaluation of a High Pressure Ratio Radial Turbine

1992 ◽  
Author(s):  
K. R. Pullen ◽  
N. C. Baines ◽  
S. H. Hill
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Pressure Ratio ◽  
Performance Measurements ◽  
Turbine Engine ◽  
High Pressure Ratio ◽  
Turbine Efficiency ◽  
Wide Range ◽  
Dimensional Parameters ◽  
Very High

A single stage, high speed, high pressure ratio radial inflow turbine was designed for a single shaft gas turbine engine in the 200 kW power range. A model turbine has been tested in a cold rig facility with correct simulation of the important non-dimensional parameters. Performance measurements over a wide range of operation were made, together with extensive volute and exhaust traverses, so that gas velocities and incidence and deviation angles could be deduced. The turbine efficiency was lower than expected at all but the lowest speed. The rotor incidence and exit swirl angles, as obtained from the rig test data, were very similar to the design assumptions. However, evidence was found of a region of separation in the nozzle vane passages, presumably caused by a very high curvature in the endwall just upstream of the vane leading edges. The effects of such a separation are shown to be consistent with the observed performance.

Simulation of Premixed and Partially Premixed Jet-in-Crossflow Flames at High-Pressure

2021 ◽  
Author(s):  
Bernhard Stiehl ◽  
Michelle Otero ◽  
Tommy Genova ◽  
Tyler Worbington ◽  
Jonathan Reyes ◽  
...  
Keyword(s):  
High Pressure ◽  
Jet In Crossflow ◽  
Partially Premixed

scholarly journals High-Pressure Angle Gears: Comparison to Typical Gear Designs

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Robert F. Handschuh ◽  
Andrew J. Zakrajsek
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Spur Gear ◽  
Engine Oil ◽  
Test Facility ◽  
Space Applications ◽  
Turbine Engine ◽  
Wear Rates ◽  
Pressure Angle ◽  
Baseline Test

A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA GRC Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N m (648 in. lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20 deg pressure angle gears are the NASA GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25 deg pressure angle gears were tested. Finally, 1.59 module (16-diametral pitch), 56 tooth, 35 deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil) and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N m (630 in. lb).

Computational and Experimental Study of the Unsteady Convection of Entropy Waves Within a High Pressure Turbine Stage

2020 ◽  
Author(s):  
Lorenzo Pinelli ◽  
Michele Marconcini ◽  
Roberto Pacciani ◽  
Paolo Gaetani ◽  
Giacomo Persico
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Low Frequency ◽  
Frequency Content ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Cfd Simulations ◽  
Time Resolved ◽  
Azimuthal Position ◽  
Cfd Method

Abstract This paper describes the transport and the interaction of pulsating entropy waves generated by combustor burners within a high pressure turbine stage for aeronautical application. Experiments and Computational Fluid Dynamics (CFD) simulations were carried out in the context of the European Research Project RECORD. Experimental campaigns considering burner-representative temperature fluctuations (in terms of spot shape, fluctuation frequency and total temperature variation percentage) injected upstream of an un-cooled high-pressure gas turbine stage have been performed in the high-speed closed-loop test-rig of the Fluid Machine Laboratory (LFM) of Politecnico di Milano (Italy). The pulsating entropy waves are injected at the stage inlet in streamwise direction at four different azimuthal positions featuring a 7% over-temperature with respect to the main flow with a frequency of 90 Hz. Detailed time-resolved temperature measurements (in the range of 0–200 Hz) upstream and downstream of the stage, as well as in the stator–rotor axial gap were performed. Time-accurate CFD simulations with and without entropy fluctuations imposed at the stage inlet were performed with the TRAF code, developed by the University of Florence. A numerical post-processing procedure, based on the DFT (Discrete Fourier Transform) of the conservative variables has been implemented to extract the low frequency content connected to the entropy fluctuations. Measurements highlighted a significant attenuation of the entropy wave spot throughout their transport within the stator channel and their interaction with the rotor blade rows, highly depending on their injection azimuthal position. Simulations show an overall good agreement with the experiments on the measurement traverses, especially at the stage outlet. By exploiting the combination of experiments and simulations, the aerodynamic and thermal implications of the temperature fluctuation injected upstream of the stage were properly assessed, thus allowing suggest useful information to the designer. The comparison with the experiments confirms the accuracy of the CFD method to solve the periodic, but characterized by a low frequency content event, associated with the entropy wave fluctuation.

Cyclone Bomb hits Southern Brazil in 2020

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Ricardo Gobato ◽  
Alireza Heidari
Keyword(s):  
High Pressure ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Satellite Images ◽  
The State ◽  
Southern Brazil ◽  
Santa Catarina ◽  
High Area ◽  
South Of Brazil ◽  
Rapid Drop

An “explosive extratropical cyclone” is an atmospheric phenomenon that occurs when there is a very rapid drop in central atmospheric pressure. This phenomenon, with its characteristic of rapidly lowering the pressure in its interior, generates very intense winds and for this reason it is called explosive cyclone, bomb cyclone. With gusts recorded of 116 km/h, atmospheric phenomenon – “cyclone bomb” (CB) hit southern Brazil on June 30, the beginning of winter 2020, causing destruction in its influence over. One of the cities most affected was Chapecó, west of the state of Santa Catarina. The satellite images show that the CB generated a low pressure (976 mbar) inside it, generating two atmospheric currents that moved at high speed. In a northwest-southeast direction, Bolivia and Paraguay, crossing the states of Parana and Santa Catarina, and this draft that hit the south of Brazil, which caused the destruction of the affected states.  Another moving to Argentina, southwest-northeast direction, due to high area of high pressure (1022 mbar). Both enhanced the phenomenon.

YSS YXM4

Alloy Digest ◽  
2019 ◽  
Vol 68 (11) ◽  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Physical Properties ◽  
Tool Steel ◽  
High Speed ◽  
Temperature Performance

Abstract YSS YXM4 is a cobalt-alloyed molybdenum high-speed tool steel with resistance to abrasion, seizure, and deformation under high pressure. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance. Filing Code: TS-780. Producer or source: Hitachi Metals America, Ltd.

scholarly journals Modeling and Optimization of Microwave-Based Bio-Jet Fuel from Coconut Oil: Investigation of Response Surface Methodology (RSM) and Artificial Neural Network Methodology (ANN)

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 295
Author(s):  
Mei Yin Ong ◽  
Saifuddin Nomanbhay ◽  
Fitranto Kusumo ◽  
Raja Mohamad Hafriz Raja Shahruzzaman ◽  
Abd Halim Shamsuddin
Keyword(s):  
Statistical Tests ◽  
Coconut Oil ◽  
Jet Fuel ◽  
Molar Ratio ◽  
Ann Model ◽  
Fuel Production ◽  
Turbine Engine ◽  
Renewable Fuel ◽  
American Society ◽  
Better Than

In this study, coconut oils have been transesterified with ethanol using microwave technology. The product obtained (biodiesel and FAEE) was then fractional distillated under vacuum to collect bio-kerosene or bio-jet fuel, which is a renewable fuel to operate a gas turbine engine. This process was modeled using RSM and ANN for optimization purposes. The developed models were proved to be reliable and accurate through different statistical tests and the results showed that ANN modeling was better than RSM. Based on the study, the optimum bio-jet fuel production yield of 74.45 wt% could be achieved with an ethanol–oil molar ratio of 9.25:1 under microwave irradiation with a power of 163.69 W for 12.66 min. This predicted value was obtained from the ANN model that has been optimized with ACO. Besides that, the sensitivity analysis indicated that microwave power offers a dominant impact on the results, followed by the reaction time and lastly ethanol–oil molar ratio. The properties of the bio-jet fuel obtained in this work was also measured and compared with American Society for Testing and Materials (ASTM) D1655 standard.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

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