Search NASA⌕ Search

SEARCH · Search NASA

Results for “duct system”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Advanced liquid oxygen (LO2) propellant conditioning concept testing

Advanced methods of liquid oxygen (LO2) propellant conditioning were studied as part of an effort for increasing reliability and operability while reducing cost of future heavy lift launch vehicles. The most promising conditioning concept evaluated was no-bleed (passive recirculation) followed by low-bleed, helium injection, and use of a recirculation line. Full-scale cryogenic testing was performed with a sloped feedline test article to validate models of behavior of LO2 in the feedline and to prove no-bleed feasibility. Test data are also intended to help generate design guidelines for the development of a main propulsion system feed duct. A design-of-experiments matrix of over 100 tests was developed to test all four propellant conditioning concepts and the impact of design parameters on the concepts. Liquid nitrogen was used as the test fluid. The work for this project was conducted from October 1992 through January 1994 at the hydrogen cold flow facility of the west test area of MSFC. Test data have shown that satisfactory temperatures are being obtained for the no-bleed conditioning concept.

Perry, G. L. E.↗
NASA NTRS2010

International Space Station Common Cabin Air Assembly Condensing Heat Exchanger Hydrophilic Coating Failures and Lessons Learned

The ability to control the temperature and humidity of an environment or habitat is critical for human survival. These factors are important to maintaining human health and comfort, as well as maintaining mechanical and electrical equipment in good working order to support the human and to accomplish mission objectives. The temperature and humidity of the International Space Station (ISS) United States On-orbit Segment (USOS) cabin air is controlled by the Common Cabin Air Assembly (CCAA). The CCAA consists of a fan, a condensing heat exchanger (CHX), an air/water separator, temperature and liquid sensors, and electrical controlling hardware and software. The CHX is the primary component responsible for control of temperature and humidity. The CCAA CHX contains a chemical coating that was developed to be hydrophilic and thus attract water from the humid influent air. This attraction forms the basis for water removal and therefore cabin humidity control. However, there have been several instances of CHX coatings becoming hydrophobic and repelling water. When this behavior is observed in an operational CHX, the unit s ability to remove moisture from the air is compromised and the result is liquid water carryover into downstream ducting and systems. This water carryover can have detrimental effects on the cabin atmosphere quality and on the health of downstream hardware. If the water carryover is severe and widespread, this behavior can result in an inability to maintain humidity levels in the USOS. This paper will describe the operation of the five CCAAs within in the USOS, the potential causes of the hydrophobic condition, and the impacts of the resulting water carryover to downstream systems. It will describe the history of this behavior and the actual observed impacts to the ISS USOS. Information on mitigation steps to protect the health of future CHX hydrophilic coatings and potential remediation techniques will also be discussed.

Balistreri, Steven F.↗
NASA NTRS2013

International Space Station Common Cabin Air Assembly Condensing Heat Exchanger Hydrophilic Coating Operation, Recovery, and Lessons Learned

The ability to control the temperature and humidity of an environment or habitat is critical for human survival. These factors are important to maintaining human health and comfort, as well as maintaining mechanical and electrical equipment in good working order to support the human and to accomplish mission objectives. The temperature and humidity of the International Space Station (ISS) United States On-orbit Segment (USOS) cabin air is controlled by the Common Cabin Air Assembly (CCAA). The CCAA consists of a fan, a condensing heat exchanger (CHX), an air/water separator, temperature and liquid sensors, and electrical controlling hardware and software. The CHX is the primary component responsible for control of temperature and humidity. The CCAA CHX contains a chemical coating that was developed to be hydrophilic and thus attract water from the humid influent air. This attraction forms the basis for water removal and therefore cabin humidity control. However, there have been several instances of CHX coatings becoming hydrophobic and repelling water. When this behavior is observed in an operational CHX in the ISS segments, the unit s ability to remove moisture from the air is compromised and the result is liquid water carryover into downstream ducting and systems. This water carryover can have detrimental effects on the ISS cabin atmosphere quality and on the health of downstream hardware. If the water carryover is severe and widespread, this behavior can result in an inability to maintain humidity levels in the USOS. This paper will describe the operation of the five CCAAs within the USOS, the potential causes of the hydrophobic condition, and the impacts of the resulting water carryover to downstream systems. It will describe the history of this behavior and the actual observed impacts to the ISS USOS. Information on mitigation steps to protect the health of future CHX hydrophilic coatings as well as remediation and recovery of the full heat exchanger will be discussed.

Balistreri, Steven F.↗
NASA NTRSDate not supplied

NASA’s Quiet Electric ENgines (QUEEN): Thermal Analysis and Testing of the Electronic Speed Controller (ESC)

An electric ducted fan system was tested at the NASA Glenn Research Center. Main components of the system include a commercial-off-the-Shelf (COTS) fan and motor, electronic speed controller, and cooling system. Motor speed, voltage, current, and temperatures were measured in this static ground test of the propulsor. The thermal performance of the Electronic Speed Controller (ESC) was also measured using two different methods to cool the ESC: air cooling and cold plate cooling. This propulsor prototype is one of NASA’s Quiet Electric ENgines (QUEENs) and is designated the ‘QUEEN V1.’ The Quiet Electric Engines are being developed for the 25% scale model of the Subsonic Single Aft Engine (SUSAN) Flight Research Vehicle and are intended to explore the potential of distributed electric propulsion for large regional single-aisle aircraft. Lessons learned will be used to guide development of future QUEEN prototypes and thermal management systems.

Firas G Asfoor↗
NASA NTRS1993

Automated Alignment And Inspection Of Duct Welds

Machine vision system being developed for use in aligning ends of two round ducts before welding ends together and inspecting welded ducts for alignment after welding. System makes consistent, objective measurements quickly. Improves quality and reliability of welds, reduces need for rework, and reduces alignment and inspection time, thereby reducing cost of manufacture.

Cross, George S.↗
NASA NTRS1981

Design and development of the combustor inlet diffuser for the NASA/GE energy efficient engine

Results of an experimental investigation of the aerodynamic performance of a split duct annular combustor inlet diffuser system are presented. Several diffuser configurations were investigated in 3X-scale water table tests and the preferred design was evaluated in full-scale annular airflow model tests. Pressure recovery and flow losses were determined as a function of prediffuser inlet velocity profile, flow extraction at the prediffuser exit, and distribution of flow in the combustor. Inlet velocity profile and turbulence levels were found to have a pronounced effect on system performance. Flow extraction at the prediffuser exit was found to have little influence on system performance. Generally, the annular split duct diffuser system was found to satisfy the performance objectives for the engine.

Sabla, P. E.↗
NASA NTRS1972

Drive turbine systems for 20-inch turbofan simulators. 1: Duct turbine design

A study was made to evolve the turbine drive systems for 20-inch turbofan engine simulators. The fan designs used in the simulators included single-stage and two-stage configurations that covered a wide range of rotative speed and power requirement. The objective assumed for the study was to evolve one core turbine design that could drive all of the single-stage fans and, when operated in combination with one duct turbine design, drive all of the two-stage fans. The duct turbine power output is then needed to determine the make-up power required of the core turbine over the range of two-stage fan operating conditions. The duct turbine design analysis is reported and includes the selection of the duct turbine velocity diagram, a description of the blade design, and a determination of its off-design performance. Adjustable stators were found to be quite advantageous to the duct turbine off-design operation. The use of adjustable stators enabled the duct turbine to accommodate fan mass flow at all operating points and caused the duct turbine power output to increase as the total power requirement increased. This in turn resulted in a core turbine make-up power requirement that was not significantly greater than that required for driving the single-stage fans.

Whitney, W. J.↗
NASA NTRS1976

Aero-acoustic tests of duct-burning turbofan exhaust nozzles

The acoustic and aerodynamic characteristics of several exhaust systems suitable for duct burning turbofan engines are evaluated. Scale models representing unsuppressed coannular exhaust systems are examined statically under varying exhaust conditions. Ejectors with both hardwall and acoustically treated inserts are investigated.

Kozlowski, H.↗
NASA NTRS1991

Lightweight Valve Closes Duct Quickly

Expanding balloon serves as lightweight emergency valve to close wide duct. Uninflated balloon stored in housing of duct. Pad resting on burst diaphragm protects balloon from hot gases in duct. Once control system triggers valve, balloon inflates rapidly to block duct. Weighs much less than does conventional butterfly, hot-gas, or poppet valve capable of closing duct of equal diameter.

Fournier, Walter L.↗
NASA NTRS1991

Composite load spectra for select space propulsion structural components

The objective of this program is to develop generic load models with multiple levels of progressive sophistication to simulate the composite (combined) load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen posts and system ducting. The first approach will consist of using state of the art probabilistic methods to describe the individual loading conditions and combinations of these loading conditions to synthesize the composite load spectra simulation. The second approach will consist of developing coupled models for composite load spectra simulation which combine the deterministic models for composite load dynamic, acoustic, high pressure, and high rotational speed, etc., load simulation using statistically varying coefficients. These coefficients will then be determined using advanced probabilistic simulation methods with and without strategically selected experimental data.

Newell, J. F.↗
NASA NTRS1991

Composite load spectra for select space propulsion structural components

The objective of this program is to develop generic load models with multiple levels of progressive sophistication to simulate the composite load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen (LOX) posts and system ducting. These models will be developed using two independent approaches. The first approach consists of using state-of-the-art probabilistic methods to describe the individual loading conditions and combinations of these loading conditions to synthesize the composite load spectra simulation. The methodology required to combine the various individual load simulation models (hot-gas dynamic, vibrations, instantaneous position, centrifugal field, etc.) into composite load spectra simulation models will be developed under this program. A computer code incorporating the various individual and composite load spectra models will be developed to construct the specific load model desired. The second approach, which is covered under the options portion of the contract, will consist of developing coupled models for composite load spectra simulation which combine the (deterministic) models for composite load dynamic, acoustic, high-pressure and high rotational speed, etc., load simulation using statistically varying coefficients. These coefficients will then be determined using advanced probabilistic simulation methods with and without strategically selected experimental data. This report covers the efforts of the third year of the contract. The overall program status is that the turbine blade loads have been completed and implemented. The transfer duct loads are defined and are being implemented. The thermal loads for all components are defined and coding is being developed. A dynamic pressure load model is under development. The parallel work on the probabilistic methodology is essentially completed. The overall effort is being integrated in an expert system code specifically developed for this project.

Newell, J. F.↗
NASA NTRS1979

The effects of air leaks on solar air heating systems

This paper presents the results of an investigation to determine the effects of leakages in collector and duct work on the system performance of a typical single-family residence solar air heating system. Positive (leakage out) and negative (leakage in) pressure systems were examined. Collector and duct leakage rates were varied from 10 to 30 percent of the system flow rate. Within the range of leakage rates investigated, solar contribution to heated space and domestic hot water loads was found to be reduced up to 30 percent from the no-leak system contribution with duct leakage equally divided between supply and return duct; with supply duct leakage greater than return leakage a reduction of up to 35 percent was noted. The negative pressure system exhibited a reduction in solar contribution somewhat larger than the positive pressure system for the same leakage rates.

Elkin, R.↗
NASA NTRS2016

Active Flow Control (AFC) and Insect Accretion and Mitigation (IAM) System Design and Integration on the Boeing 757 ecoDemonstrator

This paper presents a systems overview of how the Boeing and NASA team designed, analyzed, fabricated, and integrated the Active Flow Control (AFC) technology and Insect Accretion Mitigation (IAM) systems on the Boeing 757 ecoDemonstrator. The NASA Environmentally Responsible Aviation (ERA) project partnered with Boeing to demonstrate these two technology systems on a specially outfitted Boeing 757 ecoDemonstrator during the spring of 2015. The AFC system demonstrated attenuation of flow separation on a highly deflected rudder and increased the side force generated. This AFC system may enable a smaller vertical tail to provide the control authority needed in the event of an engine failure during takeoff while still operating in a conventional manner over the rest of the flight envelope. The AFC system consisted of ducting to obtain air from the Auxiliary Power Unit (APU), a control valve to modulate the system mass flow, a heat exchanger to lower the APU air temperature, and additional ducting to deliver the air to the AFC actuators located on the vertical tail. The IAM system demonstrated how to mitigate insect residue adhesion on a wing's leading edge. Something as small as insect residue on a leading edge can cause turbulent wedges that interrupt laminar flow, resulting in an increase in drag and fuel use. The IAM system consisted of NASA developed Engineered Surfaces (ES) which were thin aluminum sheet substrate panels with coatings applied to the exterior. These ES were installed on slats 8 and 9 on the right wing of the 757 ecoDemonstrator. They were designed to support panel removal and installation in one crew shift. Each slat accommodated 4 panels. Both the AFC and IAM flight test were the culmination of several years of development and produced valuable data for the advancement of modern aircraft designs.

Alexander, Michael G.↗
NASA NTRSDate not supplied

Source Diagnostic Fan II (22-inch) Duct Mode Characteristics as Measured by the Rotating Rake Mode Measurement System while Operated in the NASA Glenn 9x15 Low Speed Wind Tunnel

The second entry of the Source Diagnostic Test (SDT2) was a continuation of the first SDT entry with additional parameters tested. The rotor, stators, and general flow path hardware used in SDT2 were the same as those for SDT1. This included a radial baseline set of stator vanes, which had a vane count such that the rotor-stator interaction at the fan blade passing fundamental was cut-off, as is typical for modern turbofans. Two sets of stator vanes were designed and tested with a count generating a cut-on rotor-stator interaction at the fan blade passing fundamental. One of the sets maintained the no aerodynamic sweep as the radial baseline, the other was designed with leading edge sweep with the intent to generate lower noise. The NASA Glenn Research Center’s Rotating Rake Mode Measurement System was utilized to obtain a complete map of the acoustic duct modes present. The system is a radial rake immersed into the duct that continuously rotates about the duct centerline. For each of the three stator vane configurations, data were acquired at several different fan speeds which included nominal, approach, cutback, and takeoff conditions. Analysis of the mode power level results at the fan fundamentals showed the improved designed set resulted in lower rotor-stator interaction mode acoustic levels. Multiple-pure tones generated by the M5 rotor in the inlet were also measured.

Turbofan, Duct Modes↗
NASA NTRSDate not supplied

Source Diagnostic Fan II (22-inch) Duct Mode Characteristics as Measured by the Rotating Rake Mode Measurement System while Operated in the NASA Glenn 9x15 Low Speed Wind Tunnel

The second entry of the Source Diagnostic Test (SDT2) was a continuation of the first SDT entry with additional parameters tested. The rotor, stators, and general flow path hardware used in SDT2 were the same as those for SDT1. This included a radial baseline set of stator vanes, which had a vane count such that the rotor-stator interaction at the fan blade passing fundamental was cut-off, as is typical for modern turbofans. Two sets of stator vanes were designed and tested with a count generating a cut-on rotor-stator interaction at the fan blade passing fundamental. One of the sets maintained the no aerodynamic sweep as the radial baseline, the other was designed with leading edge sweep with the intent to generate lower noise. The NASA Glenn Research Center’s Rotating Rake Mode Measurement System was utilized to obtain a complete map of the acoustic duct modes present. The system is a radial rake emersed into the duct that continuously rotates about the duct centerline. For each of the three stator vane configurations, data were acquired at several different fan speeds which included nominal, approach, cutback, and takeoff conditions. Analysis of the mode power level results at the fan fundamentals showed the improved designed set resulted in lower rotor-stator interaction mode acoustic levels. Multiple-pure tones generated by the M5 rotor in the inlet were also measured.

Turbofan↗
NASA NTRS1938

Preliminary Full-Scale Wind-Tunnel Investigation of Wing Ducts for Radiators, Special Report

Wing ducts for liquid-cooled engine radiators have been investigated in the N.A.C.A. full-scale wind tunnel on a large model airplane. Th e tests were made to determine the relative merits of several types of duct and radiator installations for an airplane of a particular des ign. In the test program the principal duct dimensions were system atically varied, and the results are therefore somewhat applicable to the general problems of wing duct design, although they should be co nsidered as preliminary and only indicative of the inherent possibil ities.

Silverstein, Abe↗
NASA NTRS2003

Aero-Propulsion Technology (APT) Task V Low Noise ADP Engine Definition Study

A study was conducted to identify and evaluate noise reduction technologies for advanced ducted prop propulsion systems that would allow increased capacity operation and result in an economically competitive commercial transport. The study investigated the aero/acoustic/structural advancements in fan and nacelle technology required to match or exceed the fuel burned and economic benefits of a constrained diameter large Advanced Ducted Propeller (ADP) compared to an unconstrained ADP propulsion system with a noise goal of 5 to 10 EPNDB reduction relative to FAR 36 Stage 3 at each of the three measuring stations namely, takeoff (cutback), approach and sideline. A second generation ADP was selected to operate within the maximum nacelle diameter constrain of 160 deg to allow installation under the wing. The impact of fan and nacelle technologies of the second generation ADP on fuel burn and direct operating costs for a typical 3000 nm mission was evaluated through use of a large, twin engine commercial airplane simulation model. The major emphasis of this study focused on fan blade aero/acoustic and structural technology evaluations and advanced nacelle designs. Results of this study have identified the testing required to verify the interactive performance of these components, along with noise characteristics, by wind tunnel testing utilizing and advanced interaction rig.

Holcombe, V.↗
NASA NTRS1978

Review of the Rhein-Flugzeugbau Wankel powered aircraft program

The development of light aircraft with special emphasis on modern propulsion systems and production is discussed in terms of the application of rotary engines to aircraft. Emphasis is placed on the integrated ducted-fan propulsion system using rotary engines.

Riethmueller, M.↗