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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.

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NASA NTRS2023

Actively Controlled Louver for Human Spacecraft Radiator Ultraviolet (UV), Dust, and Freeze Protection

This paper examines the use of actively controlled louvers to attenuate UV and dust, as well as mitigate freezing concerns for human spacecraft radiators during Artemis missions. Artemis missions to the lunar orbit or surface will expose the radiators to high energy UV radiation and dust, which will degrade the radiator’s coating emissivity and consequently reduce heat rejection performance. In addition, subfreezing environmental temperatures during transit to lunar orbit and nighttime on lunar south pole can rupture coolant tubes, reduce heat rejection performance, and worst-case scenario result in a Loss of Mission (LOM). Louver technology would be a promising solution to maintaining radiator performance and integrity for Artemis missions, but heritage louvers are passively controlled. This technology needs maturing to active control, or motor actuation, to achieve faster thermal response times. Actively controlled louver design considerations are discussed in this paper. The analysis that follows shows actively controlled louvers can attenuate high energy UV radiation and dust, as well as protect the coolant from freezing.

Louver↗

NASA NTRS1972

A liquid cooled garment temperature controller based on sweat rate

An automatic controller for liquid cooled space suits is reported that utilizes human sweat rate as the primary input signal. The controller is so designed that the coolant inlet temperature is inversely proportional to the subject's latent heat loss as evidenced by evaporative water loss.

Chambers, A. B.↗

NASA NTRS1975

Final S020 Skylab experiment report

After the loss of the meteroid shield required using the solar scientific airlock to erect the sun shade, methods were improvised to operate the S020 experiment on EVA's. Almost no data was obtained in the wavelength range 10 to 110 A. From 110 to 280 A the spectra were 10 to 100 time less intense than expected. A probable cause in loss of instrument sensitivity is the contamination of the filters by the spacecraft coolant. A list of observed lines in presented. Although less data was obtained than expected, several lines not previously observed were recorded; and the spectra serve to confirm many very faintly observed weak lines recorded from sounding rockets by other experiments.

Tousey, R.↗

NASA NTRS1989

A generalized one-dimensional computer code for turbomachinery cooling passage flow calculations

A generalized one-dimensional computer code for analyzing the flow and heat transfer in the turbomachinery cooling passages was developed. This code is capable of handling rotating cooling passages with turbulators, 180 degree turns, pin fins, finned passages, by-pass flows, tip cap impingement flows, and flow branching. The code is an extension of a one-dimensional code developed by P. Meitner. In the subject code, correlations for both heat transfer coefficient and pressure loss computations were developed to model each of the above mentioned type of coolant passages. The code has the capability of independently computing the friction factor and heat transfer coefficient on each side of a rectangular passage. Either the mass flow at the inlet to the channel or the exit plane pressure can be specified. For a specified inlet total temperature, inlet total pressure, and exit static pressure, the code computers the flow rates through the main branch and the subbranches, flow through tip cap for impingement cooling, in addition to computing the coolant pressure, temperature, and heat transfer coefficient distribution in each coolant flow branch. Predictions from the subject code for both nonrotating and rotating passages agree well with experimental data. The code was used to analyze the cooling passage of a research cooled radial rotor.

Kumar, Ganesh N.↗

NASA NTRS1989

A generalized one dimensional computer code for turbomachinery cooling passage flow calculations

Kumar, Ganesh N.↗

NASA NTRS1977

Experimental flow coefficients of a full-coverage film-cooled-vane chamber

Ambient- and elevated-temperature flow tests were performed on a four-times-actual-size model of an impingement- and film-cooled segment of a core engine turbine vane. Tests were conducted with the impingement and film cooling plates combined to form a chamber and also with each of the individual separated plates. For the combined tests, the proximity of the film cooling plate affected the flow of coolant through the impingement plate, but not conversely. Impingement flow is presented in terms of a discharge coefficient, and the film cooling flow discharging into still air with no main stream gas flow is presented in terms of a total pressure-loss coefficient. The effects of main stream gas flow on discharge from the film cooling holes are evaluated as a function of coolant to main-stream gas momentum flux ratio. A smoothing technique is developed that identifies and helps reduce flow measurement data scatter.

Meitner, P. L.↗

NASA NTRS2006

Sealing in Turbomachinery

Clearance control is of paramount importance to turbomachinery designers and is required to meet today's aggressive power output, efficiency, and operational life goals. Excessive clearances lead to losses in cycle efficiency, flow instabilities, and hot gas ingestion into disk cavities. Insufficient clearances limit coolant flows and cause interface rubbing, overheating downstream components and damaging interfaces, thus limiting component life. Designers have put renewed attention on clearance control, as it is often the most cost effective method to enhance system performance. Advanced concepts and proper material selection continue to play important roles in maintaining interface clearances to enable the system to meet design goals. This work presents an overview of turbomachinery sealing to control clearances. Areas covered include: characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitations issues.

Chupp, Raymond E.↗

NASA NTRS1985

Rocket thrust chamber thermal barrier coatings

Subscale rocket thrust chamber tests were conducted to evaluate the effectiveness and durability of thin yttria stabilized zirconium oxide coatings applied to the thrust chamber hot-gas side wall. The fabrication consisted of arc plasma spraying the ceramic coating and bond coat onto a mandrell and then electrodepositing the copper thrust chamber wall around the coating. Chambers were fabricated with coatings .008, and .005 and .003 inches thick. The chambers were thermally cycled at a chamber pressure of 600 psia using oxygen-hydrogen as propellants and liquid hydrogen as the coolant. The thicker coatings tended to delaminate, early in the cyclic testing, down to a uniform sublayer which remained well adhered during the remaining cycles. Two chambers with .003 inch coatings were subjected to 1500 thermal cycles with no coating loss in the throat region, which represents a tenfold increase in life over identical chambers having no coatings. An analysis is presented which shows that the heat lost to the coolant due to the coating, in a rocket thrust chamber design having a coating only in the throat region, can be recovered by adding only one inch to the combustion chamber length.

Quentmeyer, R. J.↗

NASA NTRS2014

The ISS 2B PVTCS Ammonia Leak: An Operational History

In 2006, the Photovoltaic Thermal Control System (PVTCS) for the International Space Station's 2B power channel began leaking ammonia at a rate of approximately 1.5lbm/year (out of a starting approximately 53lbm system ammonia mass). Initially, the operations strategy was "feed the leak," a strategy successfully put into action via Extra Vehicular Activity during the STS‐134 mission. During this mission the system was topped off with ammonia piped over from a separate thermal control system. This recharge was to have allowed for continued power channel operation into 2014 or 2015, at which point another EVA would have been required. Without these periodic EVAs to refill the 2B coolant system, the channel would eventually leak enough fluid as to risk pump cavitation and system failure, resulting in the loss of the 2B power channel - the most critical of the Space Station's 8 power channels. In mid‐2012, the leak rate increased to approximately 5lbm/year. Once discovered, an EVA was planned and executed within a 5 week timeframe to drastically alter the architecture of the PVTCS via connection to a dormant thermal control system not intended to be utilized as anything other than spare components. The purpose of this rerouting of the TCS was to increase system volume and to isolate the photovoltaic radiator, thought to be the likely leak source. This EVA was successfully executed on November 1st, 2012 and left the 2B PVTCS in a configuration where the system was now being adequately cooled via a totally different radiator than what the system was designed to utilize. Unfortunately, data monitoring over the next several months showed that the isolated radiator was not leaking, and the system itself continued to leak steadily until May 9th, 2013. It was on this day that the ISS crew noticed the visible presence of ammonia crystals escaping from the 2B channel's truss segment, signifying a rapid acceleration of the leak from 5lbm/year to 5lbm/day. Within 48 hours of the crew noticing the leak, an EVA was in progress to replace the coolant pump - the only other replaceable leak source. This paper will explore the management of the 2B PVTCS leak from the operations perspective. It will discuss the methodology of performing the STS‐134 refill, the considerations and contingency plans which went into the architectural overhaul of the system in 2012, and the unprecedented effort which went into the EVA response to the visible leak of May 2013. In particular the paper will focus on the techniques utilized by flight controllers to monitor the system health and to respond to such instances as the rapid May 2013 leak by putting the electrical system in a safe configuration for loss of cooling, and will use recorded telemetry of these events to describe system response to EVA crew and ground actions. It will discuss the innovative design for redundancy of the integrated truss structure's cooling systems which allowed for this leak to be managed with minimal impact to other ISS operations and electrical services, contrasted against the real unintended operations consequences of utilizing the flexibility of the spacecraft's design in this manner. The paper will discuss how the training of the crew and flight controller personnel has adapted to the changing architecture of the power system and the unpredictable nature of the 2B leak.

Vareha, Anthony↗

NASA NTRS1989

Coolant side heat transfer with rotation. Task 3 report: Application of computational fluid dynamics

An experimental and analytical program was conducted to investigate heat transfer and pressure losses in rotating multipass passages with configurations and dimensions typical of modern turbine blades. The objective of this program is the development and verification of improved analysis methods that will form the basis for a design system that will produce turbine components with improved durability. As part of this overall program, a technique is developed for computational fluid dynamics. The specific objectives were to: select a baseline CFD computer code, assess the limitations of the baseline code, modify the baseline code for rotational effects, verify the modified code against benchmark experiments in the literature, and to identify shortcomings in the code as revealed by the verification. The Pratt and Whitney 3D-TEACH CFD code was selected as the vehicle for this program. The code was modified to account for rotating internal flows, and these modifications were evaluated for flow characteristics of those expected in the application. Results can make a useful contribution to blade internal cooling.

Kopper, F. C.↗

NASA NTRS1991

Flow boiling with enhancement devices for cold plate coolant channel design

Future space exploration and commercialization will require more efficient heat rejection systems. For the required heat transfer rates, such systems must use advanced heat transfer techniques. Forced two phase flow boiling heat transfer with enhancements falls in this category. However, moderate to high quality two phase systems tend to require higher pressure losses. This report is divided into two major parts: (1) Multidimensional wall temperature measurement and heat transfer enhancement for top heated horizontal channels with flow boiling; and (2) Improved analytical heat transfer data reduction for a single side heated coolant channel. Part 1 summarizes over forty experiments which involve both single phase convection and flow boiling in a horizontal channel heated externally from the top side. Part 2 contains parametric dimensionless curves with parameters such as the coolant channel radius ratio, the Biot number, and the circumferential coordinate.

Boyd, Ronald D.↗

NASA NTRS1973

Temperature controller for a fluid cooled garment

An automatic controller for controlling the inlet temperature of the coolant to a fluid cooled garment without requiring skin sensors is described. Temperature is controlled by the wearer's evaporative water loss rate.

Chambers, A. B.↗

NASA NTRS1983

Feasibility of water injection into the turbine coolant to permit gas turbine contingency power for helicopter application

A system which would allow a substantially increased output from a turboshaft engine for brief periods in emergency situations with little or no loss of turbine stress rupture life is proposed and studied analytically. The increased engine output is obtained by overtemperaturing the turbine; however, the temperature of the compressor bleed air used for hot section cooling is lowered by injecting and evaporating water. This decrease in cooling air temperature can offset the effect of increased gas temperature and increased shaft speed and thus keep turbine blade stress rupture life constant. The analysis utilized the NASA-Navy-Engine-Program or NNEP computer code to model the turboshaft engine in both design and off-design modes. This report is concerned with the effect of the proposed method of power augmentation on the engine cycle and turbine components. A simple cycle turboshaft engine with a 16:1 pressure ratio and a 1533 K (2760 R) turbine inlet temperature operating at sea level static conditions was studied to determine the possible power increase and the effect on turbine stress rupture life that could be expected using the proposed emergency cooling scheme. The analysis showed a 54 percent increse in output power can be achieved with no loss in gas generator turbine stress rupture life. A 231 K (415 F) rise in turbine inlet temperature is required for this level of augmentation. The required water flow rate was found to be .0109 kg water per kg of engine air flow.

Vanfossen, G. J.↗

NASA NTRS1999

Aero-Thermo-Structural Design Optimization of Internally Cooled Turbine Blades

A set of robust and computationally affordable inverse shape design and automatic constrained optimization tools have been developed for the improved performance of internally cooled gas turbine blades. The design methods are applicable to the aerodynamics, heat transfer, and thermoelasticity aspects of the turbine blade. Maximum use of the existing proven disciplinary analysis codes is possible with this design approach. Preliminary computational results demonstrate possibilities to design blades with minimized total pressure loss and maximized aerodynamic loading. At the same time, these blades are capable of sustaining significantly higher inlet hot gas temperatures while requiring remarkably lower coolant mass flow rates. These results suggest that it is possible to design internally cooled turbine blades that will cost less to manufacture, will have longer life span, and will perform as good, if not better than, film cooled turbine blades.

Dulikravich, G. S.↗

NASA NTRS1982

Thermionic technology infrastructure for space power

An assessment is made of the potential effectiveness, designs, and technological difficulties involved in the construction of space nuclear reactors coupled to thermionic energy converters (TEC). The TECs can be positioned either inside or outside of the reactor core. The out-of-core design lowers the reactor shielding requirements, as well as removing the need for mechanically pumped coolant for the reactor. R&D is still needed for the heat pipes for the reactor and the collectors, electrical insulation, and to reduce the potential losses in the interelectrode space. A cylindrical converter for the out-of-core configuration consists of a tungsten emitter heated by a tungsten-lithium heat pipe. The collector is a layer of tungsten oxide deposited on a Nb-1%Zr alloy, and has been tested at emitter temperatures of 1300-1850 K and a collector temperature range of 700-850 K. A design of a superheated thermionic converter is described, noting that a prototype has been operated at 1730 K for 12,000 hr.

Huffman, F.↗

NASA NTRS1997

Modeling Cyclic Phase Change and Energy Storage in Solar Heat Receivers

Numerical results pertaining to cyclic melting and freezing of an encapsulated phase change material (PCM), integrated into a solar heat receiver, have been reported. The cyclic nature of the present melt/freeze problem is relevant to latent heat thermal energy storage (LHTES) systems used to power solar Brayton engines in microgravity environments. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) project was developed and results compared with available experimental data. Multi-conjugate effects such as the convective fluid flow of a low-Prandtl-number fluid, coupled with thermal conduction in the phase change material, containment tube and working fluid conduit were accounted for in the model. A single-band thermal radiation model was also included to quantify reradiative energy exchange inside the receiver and losses through the aperture. The eutectic LiF-CaF2 was used as the phase change material (PCM) and a mixture of He/Xe was used as the working fluid coolant. A modified version of the computer code HOTTube was used to generate results for comparisons with GTD data for both the subcooled and two-phase regimes. While qualitative trends were in close agreement for the balanced orbit modes, excellent quantitative agreement was observed for steady-state modes.

Hall, Carsie A., III↗

NASA NTRS1997

Parametric Analysis of Cyclic Phase Change and Energy Storage in Solar Heat Receivers

A parametric study on cyclic melting and freezing of an encapsulated phase change material (PCM), integrated into a solar heat receiver, has been performed. The cyclic nature of the present melt/freeze problem is relevant to latent heat thermal energy storage (LHTES) systems used to power solar Brayton engines in microgravity environments. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) project was developed. Multi-conjugate effects such as the convective fluid flow of a low-Prandtl-number fluid, coupled with thermal conduction in the phase change material, containment tube and working fluid conduit were accounted for in the model. A single-band thermal radiation model was also included to quantify reradiative energy exchange inside the receiver and losses through the aperture. The eutectic LiF-CaF2 was used as the phase change material (PCM) and a mixture of He/Xe was used as the working fluid coolant. A modified version of the computer code HOTTube was used to generate results in the two-phase regime. Results indicate that parametric changes in receiver gas inlet temperature and receiver heat input effects higher sensitivity to changes in receiver gas exit temperatures.

Hall, Carsie A., III↗

NASA NTRSDate not supplied

Differential Mobility Spectrometry on the ISS: Successes and Current Concerns

With the construction of the International Space Station (ISS), crew members moved from the relatively short flights of the Space Shuttle (~ 2 weeks) to missions lasting months to a year. As such, environmental monitoring needs also changed, transitioning from a reliance on archival sampling to a combination of archival sampling and in-flight data collection. In the case of trace volatile organic compound (VOC) monitoring, this in-flight monitoring was performed early on by the Volatile Organic Analyzer (VOA), a gas chromatograph-ion mobility spectrometer, which operated on the ISS for 7 years. This large, fixed-position analyzer was replaced by Air Quality Monitors (AQMs), a pair of small gas chromatograph-differential mobility spectrometers, in the spring of 2013. During their initial half decade of use, and covering multiple sets of units, the AQMs performed well, meeting all of their validation criteria and generally showing excellent accuracy when compared to the now-reduced archival samples. These instruments were also used to perform a survey of the US Operating Segment (US Lab Module, European Columbus Module, and Japanese Pressurized Module), confirming that the atmosphere in this segment is well-mixed. The AQMs were also able to provide important information in contingency situations, such as confirming that no ammonia was present on the ISS following alarms suggesting that the coolant loops had leaked in January 2015. As the fleet of AQMs has aged, though, issues of concern have arisen. These have ranged from pervasive electronics board problems to loss of sensitivity due to carbon dioxide to incorrect identification of compounds. Some of these issues are unavoidable due to the nature of the AQM’s use and preparation prior to flight. However, with the extension of the ISS to 2030 (well past its original 2024 lifetime), the fleet of AQMs will be asked to perform longer, requiring solutions to some of the inherent problems. In this presentation, we will discuss the history of the AQM on the ISS with a focus on more recent results. These results show both the continued usefulness of the AQM for atmospheric monitoring and also the current concerns, including: 1) the incorrect identification of benzene, 2) reporting of elevated isopropanol concentrations, and 3) the loss of the reactant ion peak (RIP) that must be resolved in order for the instrument to continue to serve as the primary trace VOC monitor on the ISS.

W T Wallace↗