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).

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.

Pumping Loss of Shrouded Meshed Spur Gears

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Michael J. Hurrell ◽  
Jerzy T. Sawicki
Keyword(s):  
High Speed ◽  
Spur Gear ◽  
Test Facility ◽  
Spur Gears ◽  
Cfd Analysis ◽  
Total Load ◽  
New Approach ◽  
Computational Fluid Dynamics Cfd ◽  
Loss Component ◽  
Swept Volume

Abstract High speed rotorcraft transmissions are subject to load-independent power losses consisting of drag loss and pumping loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent losses. However, tightly conforming axial shrouds can result in an increase in the pumping loss component. Quantifying the pumping loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating pumping loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag loss and pumping loss of a shrouded spur gear pair have been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamics (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating pumping power loss of shrouded gear transmissions.

Pumping Loss of Shrouded Meshed Spur Gears

2020 ◽  
Author(s):  
Michael J. Hurrell ◽  
Jerzy T. Sawicki
Keyword(s):  
High Speed ◽  
Fluid Dynamic ◽  
Spur Gear ◽  
Test Facility ◽  
Spur Gears ◽  
Cfd Analysis ◽  
Total Load ◽  
New Approach ◽  
Loss Component ◽  
Swept Volume

Abstract High speed rotorcraft transmissions are subject to load-independent power losses consisting of drag loss and pumping loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent losses. However, tightly conforming axial shrouds can result in an increase in the pumping loss component. Quantifying the pumping loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating pumping loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag loss and pumping loss of a shrouded spur gear pair has been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamic (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating pumping power loss of shrouded gear transmissions.

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.

Developing a Combustor Simulator for Investigating High Pressure Turbine Aerodynamics and Heat Transfer

2004 ◽  
Author(s):  
M. D. Barringer ◽  
K. A. Thole ◽  
M. D. Polanka
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Pressure Ratio ◽  
Test Facility ◽  
Temperature Profiles ◽  
High Pressure Turbine ◽  
Blow Down ◽  
Turbine Engine ◽  
The Impact

Within a gas turbine engine, the high pressure turbine vanes are subjected to very harsh conditions from the highly turbulent and hot gases exiting the combustor. The temperature and pressure fields exiting the combustor dictate the heat transfer and aero losses that occur in the turbine passages. To better understand these effects, the goal of this work is to develop an adjustable combustor exit profile simulator for the Turbine Research Facility (TRF) at the Air Force Research Laboratory (AFRL). The TRF is a high temperature, high pressure, short duration blow-down test facility that is capable of matching several aerodynamic and thermal non-dimensional engine parameters including Reynolds number, Mach number, pressure ratio, corrected mass flow, gas-to-metal temperature ratio, and corrected speed. The research objective was to design, install, and verify a non-reacting simulator device that provides representative combustor exit total pressure and temperature profiles to the inlet of the TRF turbine test section. This required the upstream section of the facility to be redesigned into multiple concentric annuli that serve the purpose of injecting high momentum dilution jets and low momentum film cooling jets into a central annular chamber, similar to a turbine engine combustor. The design of the simulator allows for variations in injection levels to generate turbulence and pressure profiles. It also can vary the dilution and film cooling temperatures to create a variety of temperature profiles consistent with real combustors. To date, the design and construction of the simulator device has been completed. All of the hardware has been trial fitted and the flow control shutter systems have been successfully installed and tested. Currently, verification testing is being performed to investigate the impact of the generated temperature, pressure, and turbulence profiles on turbine heat transfer and secondary flow development.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document