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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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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Power Plant Testing of Ultrasonic Measurements of Temperature Distributions and Heat Fluxes to Heat Exchange Surfaces

Extreme environmental conditions are common in energy conversion applications, in which the most hardened insertion sensors often do not perform reliably for long. On the other hand, ultrasonic measurements can be acquired noninvasively, with sensitive components kept away from the damaging environment. We have previously developed the ultrasonic method for measuring the spatial distribution of temperatures in solid materials applicable when large thermal gradients are present. In the developed approach, we use the echogenically segmented ultrasound propagation path, structured to contain engineered or naturally occurring echogenic features, to produce a train of echoes in response to an external pulse of ultrasonic excitation. This paper outlines the testing results of this approach applied to the temperature distribution measurements to a waterwall of a 500 MW power-plant utility boiler. The validation results obtained over the prolonged power plant test show that the estimated temperature profile is correctly captured, and the measurement accuracy can be comparable with traditional insertion sensors, such as thermocouples. Overall, the testing has confirmed that the developed approach has matured to become an attractive alternative to conventional sensing in solving challenging problems of long-term temperature measurements in extreme environments. Heat fluxes and thermal stresses in the structure can then be characterized noninvasively using the measured temperature distribution as the basis.

Walton, Kenneth↗
DOE OSTI2025

Control and synchronization of rapid nanoscale DNA heat engine by local heating

To further activate devices based on DNA nanotechnology, we introduce an approach that notably enhances both the speed and force of DNA powered machines and artificial hinge machine. A microheater, with millisecond response, heats or recools DNA origami constructs, hybridizing or dehybridizing sticky ends. Because anything within 20 micrometers of the heater equilibrates to a programmed temperature change in milliseconds, sticky ends of a compound DNA origami machine can open and close synchronously and operate cooperatively, in phase, additively increasing the drive force compared to single pair of sticky ends DNA machine (the six-helix bundle DNA origami hinge machine). In our demonstrations, we fold and unfold two square origami with 10 pairs of complementary sticky ends to drive a bead on the end of a rod like origami to speeds exceeding 30 micrometers per second. Our device envisions the creation of complex, synchronized DNA machines.

Science & Technology - Other Topics↗
NASA NTRS1968

Heat-load simulator for heat sink design

Heat-load simulator is fabricated from 1/4-inch aluminum plate with a contact surface equal in dimensions and configuration to those of the electronic installation. The method controls thermal output to simulate actual electronic component thermal output.

Dunleavy, A. M.↗