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Viewing 1 to 30 of 2448
2015-09-22
Event
2015-06-15
Technical Paper
2015-01-2134
Tom Currie, Dan Fuleki
There is significant recent evidence that ice crystals ingested by a jet engine at high altitude can partially melt and then accrete within the forward stages of the compressor, potentially producing a loss of performance, rollback, combustor flameout, compressor damage, etc. Several studies of this ice crystal icing (ICI) phenomenon have been conducted in the past 5 years using the RATFac (Research Altitude Test Facility) altitude chamber at the National Research Council of Canada (NRCC), which includes an icing wind tunnel capable at operating at Mach numbers (M), total pressures (po) and temperatures (To) pertinent to ICI. Humidity can also be controlled and ice particles are generated with a grinder. The ice particles are entrained in a jet of sub-freezing air blowing into the tunnel inlet. Warm air from the altitude cell also enters the tunnel, where it mixes with the cold ice-laden jet, increasing the wet-bulb temperature (Twb) and inducing particle melting.
2015-06-15
Technical Paper
2015-01-2133
Joseph P. Veres, Scott M. Jones, Philip C. E. Jorgenson
The Propulsion Systems Laboratory (PSL), an altitude test facility at NASA Glenn Research Center, has been used to test a full scale turbine engine at simulated altitude operating conditions. The PSL test facility has the capability to create a continuous cloud of ice crystals that are ingested by the engine during operation at simulated altitudes. The PSL tests successfully duplicated the icing events that were experienced by this engine during flight through ice crystal clouds. During testing at the PSL, after the ice cloud was turned on, key engine performance parameters responded immediately due to ingestion of the ice crystals. The points where the performance deteriorated with time have been attributed to ice accretion in the low pressure compressor. Eight data points were analyzed in order to gain understanding of key transient engine performance parameters. Examination of the test data showed two distinct responses in the engine once the ice cloud was initiated.
2015-06-15
Technical Paper
2015-01-2107
Tom Currie, Dan Fuleki, Craig Davison
Abstract Ice crystals ingested by a jet engine at high altitude can partially melt and then accrete within the compressor, potentially causing performance loss, damage and/or flameout. Several studies of this ice crystal icing (ICI) phenomenon conducted in the RATFac (Research Altitude Test Facility) altitude chamber at the National Research Council of Canada (NRCC) have shown that liquid water is required for accretion. CFD-based tools for ICI must therefore be capable of predicting particle melting due to heat transfer from the air warmed by compression and possibly also due to impact with warm surfaces. This paper describes CFD simulations of particle melting and evaporation in the RATFac icing tunnel for the former mechanism, conducted using a Lagrangian particle tracking model combined with a stochastic random walk approach to simulate turbulent dispersion. Inter-phase coupling of heat and mass transfer is achieved with the particle source-in-cell method.
2015-06-15
Technical Paper
2015-01-2146
Matthew Feulner, Shengfang Liao, Becky Rose, Xuejun Liu
Abstract A through-flow based Monte Carlo particle trajectory simulation is used to calculate the ice crystal paths in the low pressure compressor of a high bypass ratio turbofan engine. The simulation includes a statistical ice particle breakup model due to impact on the engine surfaces. Stage-by-stage ice water content, particle size and particle velocity distributions are generated at multiple flight conditions and engine power conditions. The majority of the ice particle breakup occurs in the fan and first LPC stage. The local ice water content (IWC) within LPC is much higher than the ambient conditions due to scoop effects, centrifuging and flow-path curvature. Also the ice particles approach the stators at lower incidence angles than the air flow. The simulation results prompt the need to revisit the approach for properly setting up boundary conditions for component or cascade testing.
2015-05-13
WIP Standard
AS4726A
This specification establishes the requirements for self-locking nuts, wrenching type (i.e., hexagon, double hexagon, and spline drive), made of a corrosion and heat resistant steel of the type identified under the Unified Numbering System as UNS S66286. Classification: a. 220 ksi minimum tensile strength at room temperature and b. 850 degrees F maximum test temperature of parts. Primarily for use in aerospace propulsion systems in temperatures up to approximately 850 degrees were nuts are used with bolts capable of developing 220 ksi axial tensile strength at room temperature, and having UNJ thread form.
2015-05-08
WIP Standard
AS7459C
This procurement specification covers bolts and screws made from a low alloy, heat resistant steel of the type identified under the Unified Numbering System as UNS K14675, having UNJ profile threads. The following specification designations and their properties are covered: AS7459 195 ksi minimum ultimate tensile strength at room temperature; 145 ksi minimum ultimate tensile strength at 900 degrees F; 105 ksi stress rupture strength at 900 degrees F for 100 hours; 100 ksi tension to 10 ksi tension fatigue at room temperature; Protective treatment to be specificed on part drawing; AS7459-1 AS7459 part plated per AMS 2416, nickel-cadmium diffused plating; AS7495-2 195 ksi minimum ultimate tensile strength at room temperature; 117 ksi minimum ultimate shear strength at room temperature; protective treatment to be specified on part drawing; AS7495-3 AS7495-2 part plated per AMS 2416, nickel-cadmium diffused plating.
2015-05-07
WIP Standard
ARP1202B
This Aerospace Recommenced Practice (ARP) defines a series of ball bearings which are specifically designed to support the rotor in a dynamic balancing machine. By establishing certain bearing sizes the number of required balancing machine support adapters will be reduced. The intent is that each size bearing identified by its outside diameter and width will be capable of accommodating any bore diameter within the specified range of that size. This ARP specifies both the nominal dimensions and the tolerances for a series of ball bearings with semifinished inside diameters which are suitable for supporting gas turbine rotating components in dynamic balancing machines.
2015-05-07
WIP Standard
ARP1340B
This document specifies those requirements and procedures for periodic tests to insure maintenance of balance machine capabilities for balancing jet engine components.
2015-05-06
WIP Standard
AS7461D
This procurement specification covers aircraft-quality bolts and screws made from 6Al-4V titanium alloy of the type identified under the Unified Numbering System as UNS R56400. Primarily for aerospace propulsion system applications where high strength, light weight, fatigue rated fasteners are required for use up to approximately 600 °F.
Viewing 1 to 30 of 2448

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