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Analysis of a Coupling System of Aircraft Environmental Control and Fuel Tank Inerting Based on Membrane Separation

Beihang University-Weixing Yuan, Jiaqi Hou
CAPDI-Yan zheng
  • Technical Paper
  • 2019-01-1895
To be published on 2019-09-16 by SAE International in United States
This paper raises a coupling system of aircraft environmental control and fuel tank inerting based on membrane separation. The system applies a membrane dehumidifier to replace water vapor removal unit of heat regenerator, condenser and water separator, which is widely used in conventional aircraft environmental control system nowadays. Water vapor can travel across the membrane wall under its pressure difference without phase change, so the dehumidification process consumes no cooling capacity and the cooling capacity of the system increases. This paper first compares the thermodynamic properties of environmental control system based on membrane dehumidification and the environmental control system based on condensation. The results show that the membrane dehumidification system has bigger cooling capacity and lighter weight. For a given cooling capacity requirement of a certain aircraft, the membrane dehumidification system can use less bleed air since the temperature of the outlet air is lower. Nowadays, the fuel tanking inerting system also uses an air separation module to produce nitrogen enriched air based on membrane separation. After the air is dehumidified in membrane environmental control…
 
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Numerical Simulation of Ice Crystal Accretion Inside an Engine Core Stator

ANSYS Inc.-Shezad Nilamdeen, Vinod Singh Rao, David Switchenko, Jeyatharsan Selvanayagam, Isik Ozcer, Guido S. Baruzzi
Published 2019-06-10 by SAE International in United States
A CFD simulation methodology is presented to calculate blockage due to ice crystal icing of the IGV passages of a gas turbine engine. The computational domain consists of six components and includes the nacelle, the full bypass and the air induction section up to the second stage of the low-pressure compressor. The model is of a geared turbofan with a fan that rotates at 4,100 rpm and a low-pressure stage that rotates at 8,000 rpm. The flight conditions are based on a cruising speed of Mach 0.67 in Appendix-D icing conditions with an ice crystal content is 4.24 g/m3. Crystal bouncing, and re-entrainment is considered in the calculations, along with variable relative humidity and crystal melting due to warmer temperatures within the engine core. Total time of icing is set to 20 seconds. The CFD airflow and ice crystal simulations are performed on the full 6-stage domain. The initial icing calculation determines which stage will be chosen for a more comprehensive analysis. In this case the IGV passage was chosen for the detailed multi-shot analysis,…
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Numerical Demonstration of the Humidity Effect in Engine Icing

ANSYS Inc.-Yue Zhang, Isik Ozcer, Shezad Nilamdeen, Guido S. Baruzzi, Jeyatharsan Selvanayagam
Published 2019-06-10 by SAE International in United States
The importance of the variation of relative humidity across turbomachinery engine components for in-flight icing is shown by numerical analysis. A species transport equation for vapor has been added to the existing CFD methodology for the simulation of ice growth and water flow on engine components that are subject to ice crystal icing. This entire system couples several partial differential equations that consider heat and mass transfer between droplets, crystals and air, adding the cooling of the air due to particle evaporation to the icing simulation, increasing the accuracy of the evaporative heat fluxes on wetted walls. Three validation cases are presented for the new methodology: the first one compares with the numerical results of droplets traveling inside an icing tunnel with an existing evaporation model proposed by the National Research Council of Canada (NRC). The second one compares humidity and the reduction in the outflow total temperature to the experimental data from NASA Glenn Research Center’s Propulsion Systems Laboratory (PSL). The third case shows that the vapor model improves our icing validation of the…
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Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory

NASA John Glenn Research Center-Peter M. Struk, Juan Agui, Thomas Ratvasky, Michael King
Ohio Aerospace Institute-Tadas Bartkus, Jen-Ching Tsao
Published 2019-06-10 by SAE International in United States
This paper describes an ice-crystal icing experiment conducted at the NASA Propulsion System Laboratory during June 2018. This test produced ice shape data on an airfoil for different test conditions similar to those inside the compressor region of a turbo-fan jet engine. Mixed-phase icing conditions were generated by partially freezing out a water spray using the relative humidity of flow as the primary parameter to control freeze-out. The paper presents the ice shape data and associated conditions which include pressure, velocity, temperature, humidity, total water content, melt ratio, and particle size distribution. The test featured a new instrument traversing system which allowed surveys of the flow and cloud. The purpose of this work was to provide experimental ice shape data and associated conditions to help develop and validate ice-crystal icing accretion models. The results support previous experimental observations of a minimum melt-ratio threshold for accretion to occur as well as the existence of a plateau region where the icing severity is high for a range of melt ratios. However, a maximum limit for melt ratio,…
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Total Temperature Measurements in Icing Cloud Flows Using a Rearward Facing Probe

NASA Glenn Research Center-Juan H. Agui, Peter Struk
Ohio Aerospace Institute-Tadas Bartkus
Published 2019-06-10 by SAE International in United States
This paper reports on temperature and humidity measurements from a series of ice-crystal icing tunnel experiments conducted in June 2018 at the Propulsion Systems Laboratory at the NASA Glenn Research Center. The tests were fundamental in nature and were aimed at investigating the icing processes on a two-dimensional NACA0012 airfoil subjected to artificially generated icing clouds. Prior to the tests on the airfoil, a suite of instruments, including total temperature and humidity probes, were used to characterize the thermodynamic flow and icing cloud conditions of the facility. Two different total temperature probes were used in these tests which included a custom designed rearward facing probe and a commercial self-heating total temperature probe. The rearward facing probe, the main total temperature probe, is being designed to reduce and mitigate the contaminating effects of icing and ingestion of ice crystals and water droplets at the probe’s inlet. The probe also serves as an air-sample inlet for a light absorption based humidity measurement. The paper includes a section which discusses total temperature and humidity measurement considerations, and another…
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Effect of Icing Environment and Humidity on Reference Air Data Parameters in an Icing Tunnel

Collins Aerospace-Mac Whalen, Brian Matheis
Published 2019-06-10 by SAE International in United States
Wind tunnel facilities typically rely upon reference instrumentation combined with isentropic flow relationships to define the fluid properties in the test section. For the particular case of icing wind tunnels, the icing environment can affect the airflow such that the definition of test section parameters via isentropic relationships is not strictly correct. These influences are of particular importance for testing air data probes because the nature of the test is to evaluate the performance of a sensor directly measuring the parameters being affected. Momentum, heat, and mass transfer from the water phase to the air phase can result in total temperature and total pressure measurements in the test section that differ from those measured at an upstream station, where reference measurements are typically taken. This effect was first observed by Luers & Fiscus [1] in the context of wind tunnel tests for heavy rain conditions.
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Experimental Investigation of High Speed SLD Impact

ONERA-Virginel BODOC, Pierre Berthoumieu
Published 2019-06-10 by SAE International in United States
This paper proposes an experimental investigation of fast impinging large droplets in non-icing conditions. Two main aspects of the impact event are analyzed and discussed: the impact dynamics as a function of the surface nature and the deposition rate of the liquid on the impingement surface for various conditions. The data has been recorded and characterized at ambient pressure and a temperature of the air between 5 and 10°C using a vertical wind/droplet tunnel. To avoid the droplets evaporation the relative humidity was controlled. The morphology of impact was studied by backlighted imagery and quantitative results were obtained by image analysis. The deposition rate was obtained weighting the water accumulated on the impingement plate. Examination of splashing events images obtained on a clean surface and on blotter paper shows important differences in terms of secondary drop generation. The measurement of the deposition rate confirmed that the dynamics of drop impingement on blotter paper is not the same as impingement on a clean surface. These differences may significantly impact the development of models for icing applications.
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Photogrammetric Frost Roughness Measurements in Cold-Soaked Conditions

Baylor University-Taber Miyauchi, Stephen T. McClain, Tongxin Zhang, Dennis L. O'Neal
Federal Aviation Administration (FAA)-James T. Riley
Published 2019-06-10 by SAE International in United States
Cold-soaked fuel frost (CSFF) is a form of aircraft wing contamination that occurs when a vehicle caries sufficient fuel for multiple trips or take-offs and landings. Following the first trip, which may reach altitudes above 10,000 m (33,000 ft), the fuel for the subsequent trips is carried in the wing tanks and may reach temperatures below -25 °C. In certain times of the year at some airports, temperatures and humidity levels will form CSFF on the aircraft wing surfaces over the fuel tanks. Unless an exemption is granted for the specific aircraft model, aircraft are not allowed to takeoff if the wing surfaces are contaminated by frost. Because aircraft operators desire to minimize vehicle time spent at airports, aircraft manufacturers are expected to pursue designs that safely operate with CSFF at takeoff and to pursue certification exemptions for aircraft models enabling CSFF takeoffs. To assist manufacturers in the design of future aircraft and to assist regulators in evaluating certification exemption requests, more information about frost roughness characteristics and evolution in CSFF conditions is required. However,…
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Coating Prevents Fogging on Transparent Surfaces

  • Magazine Article
  • TBMG-34409
Published 2019-05-01 by Tech Briefs Media Group in United States

Anyone who skis, wears glasses, uses a camera, or drives a car is familiar with the problem: Coming into a humid environment from the cold causes eyewear, camera lenses, or windshields to quickly fog up. Researchers have developed a new transparent material coating that greatly reduces this effect. A few nanometers thick, the durable coating is made of gold nanoparticles embedded in non-conductive titanium oxide.

 

Environmental Degradation of Textiles

AGE-2 Air Cargo
  • Aerospace Standard
  • AIR1490C
  • Current
Published 2019-04-24 by SAE International in United States
Since cargo restraint devices made with textiles should have a predictable service life, there should be data available so that predictions can be made. This document compiles available information on textiles of the types used in air cargo restraint devices and reviews the degradation characteristics of each. Textiles are used primarily in cargo restraint nets on air cargo pallets and nonstructural containers, restraint nets installed in cargo aircraft, and similar applications.
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