Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Thermal Design”

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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Thermal design and test results for SUNLITE ultra-stable reference cavity

SUNLITE (Stanford University-NASA Laser In-Space Technology Experiment) is a space-based experiment which uses a reference cavity to provide a stable frequency reference for a terahertz laser oscillator. Thermal stability of the cavity is a key factor in attaining a stable narrow-linewidth laser beam. The mount which is used to support and align the cavity will provide thermal isolation from the environment. The baseline requirement for thermal stability of the cavity is 0.025 C/min, but the design is directed toward achieving stability well beyond this requirement to improve the science data gained. A prototype of the cavity mount was fabricated and tested to characterize the thermal performance. The thermal vacuum test involved stable high-resolution temperature measurements and stable baseplate temperature control over long durations. Based on test data, the cavity mount design satisfies the severe requirement for the cavity thermal stability.

Amundsen, Ruth M.↗
NASA NTRS1985

Thermal design of AOTV heatshields for a conical drag brake

Results are presented from an on-going study of the thermal performance of thermal protection systems for a conical drag brake type AOTV. Three types of heatshield are considered: rigid ceramic insulation, flexible ceramic blankets, and ceramic cloths. The results for the rigid insulation apply to other types of AOTV as well. Charts are presented in parametric form so that they may be applied to a variety of missions and vehicle configurations. The parameters considered include: braking maneuver heat flux and total heat load, heatshield material and thickness, heatshield thermal mass and conductivity, absorptivity and emissivity of surfaces, thermal mass of support structure, and radiation transmission through thin heatshields. Results of temperature calculations presented show trends with and sensitivities to these parameters. The emphasis is on providing information that will be useful in estimating the minimum required mass of these heatshield materials.

Pitts, W. C.↗
NASA NTRS1973

Effect of Optical Properties on Thermal Design

When considering the effect of external surface optical properties, subsystems contained within the vehicle must be considered in addition to the thermal protection system. Representative subsystem temperature limits for orbital flight (long term) and entry transients (short term) are presented.

Statham, C. L.↗
NASA NTRS2001

Thermal Design, Analysis, and Testing of the Quench Module Insert Bread Board

The science requirements for materials processing is to provide the desired PI requirements of thermal gradient, solid/liquid interface front velocity for a given processing temperature desired by the PI. Processing is performed by translating the furnace with the sample in a stationary position to minimize any disturbances to the solid/liquid interface front during steady state processing. Typical sample materials for this metals and alloys furnace are lead-tin alloys, lead-antimony alloys, and aluminum alloys. Samples must be safe to process and therefore typically are contained with hermetically sealed cartridge tubes (gas tight) with inner ceramic liners (liquid tight) to prevent contamination and/or reaction of the sample material with the cartridge tube.

Breeding Shawn↗
NASA NTRS1992

TOPEX Microwave Radiometer - Thermal design verification test and analytical model validation

The testing of the TOPEX Microwave Radiometer (TMR) is described in terms of hardware development based on the modeling and thermal vacuum testing conducted. The TMR and the vacuum-test facility are described, and the thermal verification test includes a hot steady-state segment, a cold steady-state segment, and a cold survival mode segment totalling 65 hours. A graphic description is given of the test history which is related temperature tracking, and two multinode TMR test-chamber models are compared to the test results. Large discrepancies between the test data and the model predictions are attributed to contact conductance, effective emittance from the multilayer insulation, and heat leaks related to deviations from the flight configuration. The TMR thermal testing/modeling effort is shown to provide technical corrections for the procedure outlined, and the need for validating predictive models is underscored.

Lin, Edward I.↗
NASA NTRS2004

Thermal design trades for SAFIR architecture concepts

SAFIR is a IO-meter, 4 K space telescope optimized for wavelengths between 20 microns and 1 mm. The combination of aperture diameter and telescope temperature will provide a raw sensitivity improvement of more than a factor of 1000 over presently-planned missions. The sensitivity will be comparable to that of the JWST and ALMA, but at the critical far-IR wavelengths where much of the universe's radiative energy has emerged since the origin of stars and galaxies. We examine several of the critical technologies for SAFIR which enable the large cold aperture, and present results of studies examining the telescope optics and the spacecraft thermal architecture. Both the method by which the aperture is filled, and the overall optical design for the telescope can impact the potential scientific return of SAFIR. Thermal architecture that goes far beyond the sunshades developed for the James Webb Space Telescope will be necessary to achieve the desired sensitivity of SAFIR. By combining active and passive cooling at critical points within the observatory, a significant reduction of the required level of active cooling can be obtained.

infrared telescopes↗
NASA NTRS1992

Spacelab carrier complement thermal design and performance

The present discussion of the Spacelab carrier complement, which encompasses a Module Carrier, a Module-Pallet Carrier, and a Multiplexer/Demultiplexer Pallet, gives attention to both active and passive thermal performance capabilities, and presents ground testing and analytical results obtained to date. An account is given of the prospective use of a Spacelab Multipurpose Experiment Support Structure.

Bancroft, S.↗
NASA NTRSDate not supplied

Combined Electromagnetic and Thermal Design Optimization Studies of In-Slot Cooling for UAM Electric Motors

Urban Air Mobility vehicles will require high specific power and high reliability electric motors. Motor specific power is limited by the temperature limits of stator winding insulation and the motor cooling system’s ability to extract heat from the motor windings. The temperature limits of the stator winding are set by both thermal-chemical aging and thermo-mechanical stresses. In-slot cooling is known to be able to both more effectively reduce the max hotspot temperature in a winding and the thermo-mechanical stress in a winding at a given hotspot temperature relative to external cooling jackets. In this paper, a combined electromagnetic, thermal, and mechanical optimization of in-slot cooled motors for UAM applications is completed. Initial thermal and mechanical studies of in-slot cooling topologies with a reference design were used to down select an in-slot cooled topology for optimization. Optimizations were carried out for both the in-slot cooled topology and a traditional externally cooled motor. Results show that the in-slot cooling topology can achieve a smaller mass than a traditional water jacket cooled design, but at the cost of lower efficiency due to larger required stator thicknesses and correspondingly larger stator iron loss.

Thomas Tallerico↗
NASA NTRSDate not supplied

Combined Electromagnetic and Thermal Design Optimization Studies of in-Slot Cooling for UAM Electric Motors

Abstract- Urban Air Mobility vehicles will require high specific power and high reliability electric motors. Motor specific power is limited by the temperature limits of stator windings insulation and the motor cooling system’s ability to extract heat from the motor windings. The temperature limits of the stator winding are set by both thermal-chemical aging and thermo-mechanical stresses. In-slot cooling is known to be able to both more effectively reduce the max hotspot temperature in a winding and the thermo-mechanical stress in a winding at a given hotspot temperature relative to external cooling jackets. In this paper, a combined electromagnetic, thermal, and mechanical optimization of in-slot cooled motors for UAM applications is completed. Initial thermal and mechanical studies of in-slot cooling topologies with a reference design were used to down select an in-slot cooled topology for optimization. Optimizations were carried out for a representative UAM mission profile on both the in-slot cooled topology and a traditional externally cooled motor. Results show that the in-slot cooling topology can achieve a smaller mass than a traditional water jacket cooled design, but at the cost of lower efficiency due larger required stator thicknesses and correspondingly larger stator iron loss.

Thomas Tallerico↗
NASA NTRS2008

Improved Thermal Design of a Compression Mold

A compression tool used to make 1-in. (2.5-cm) diameter disks of high-temperature polymers was designed to be shorter and of larger diameter than conventional tools to reduce heat loss to the surrounding air, thus making more efficient use of applied heat. This system is less sensitive to the amount and quality of insulation than previous tools, provides more repeatable processing, and improves the quality of the samples produced. These improvements come without increasing the weight of the punch portion of the tool over that of a conventional version, an important quality when handling lower-viscosity resins. In use, the base and body of the tool are assembled, and the polymer to be processed is placed into the body of the tool. The punch is inserted, and the assembled tool is placed into the press. A temperature/ pressure profile appropriate to the nature of the polymer is applied. A series of computational and experimental runs were made using a conventional tool to validate the computational model. The new tool design was then modeled, and when the performance showed a marked improvement, the new tool was manufactured. A new series of experimental runs showed that the thermal performance of the new tool agreed well with model predictions.

Kuczmarski, Maria A.↗
NASA NTRS1984

Cryogenic and thermal design for the Space Infrared Telescope Facility (SIRTF)

The 1-meter class cryogenically cooled Space Infrared Telescope Facility (SIRTF) planned by NASA, is scheduled for a 1992 launch. SIRTF would be deployed from the Shuttle, and placed into a sun synchronous polar orbit of 700 km. The facility has been defined for a mission with a minimum initial lifetime of one year in orbit with mission extension that could be made possible through in-orbit servicing of the superfluid helium cryogenic system, and use of a thermal control system. The superfluid dewar would use an orbital disconnect system for the tank supports, and vapor cooling of the barrel baffle. The transient analysis of the design shows that the superfluid helium tank with no active feedback comes within temperature requirements for the nominal orbital aperture heat load, quiescent instrument, and chopper conditions.

Lee, J. H.↗
NASA NTRS2017

Thermal Design for Extra-Terrestrial Regenerative Fuel Cell System

The Advanced Exploration Systems (AES) Advanced Modular Power Systems (AMPS) Project is investigating different power systems for various lunar and Martian mission concepts. The AMPS Fuel Cell (FC) team has created two system-level models to evaluate the performance of regenerative fuel cell (RFC) systems employing different fuel cell chemistries. Proton Exchange Membrane fuel cells PEMFCs contain a polymer electrolyte membrane that separates the hydrogen and oxygen cavities and conducts hydrogen cations (protons) across the cell. Solid Oxide fuel cells (SOFCs) operate at high temperatures, using a zirconia-based solid ceramic electrolyte to conduct oxygen anions across the cell. The purpose of the modeling effort is to down select one fuel cell chemistry for a more detailed design effort. Figures of merit include the system mass, volume, round trip efficiency, and electrolyzer charge power required. PEMFCs operate at around 60 C versus SOFCs which operate at temperatures greater than 700 C. Due to the drastically different operating temperatures of the two chemistries the thermal control systems (TCS) differ. The PEM TCS is less complex and is characterized by a single pump cooling loop that uses deionized water coolant and rejects heat generated by the system to the environment via a radiator. The solid oxide TCS has its own unique challenges including the requirement to reject high quality heat and to condense the steam produced in the reaction. This paper discusses the modeling of thermal control systems for an extraterrestrial RFC that utilizes either a PEM or solid oxide fuel cell.

thermal modeling↗