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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Direct numerical simulations of diffusive staircases in the Arctic

Caro, Gregory P. January 2009 (has links) (PDF)
Thesis (M.S. in Physical Oceanography)--Naval Postgraduate School, March 2009. / Thesis Advisor(s): Radko, Timour. "March 2009." Description based on title screen as viewed on April 23, 2009. Author(s) subject terms: Double-diffusion, diffusive convection, heat flux, thermohaline staircase, Includes bibliographical references (p. 39-41). Also available in print.

Development of a Novel, Manufacturing Method of Producing Cost-Effective Thin-Film Heat Flux Sensors

Cherry, Rande James 13 November 2015 (has links)
A new method of manufacturing heat flux sensors was developed using a combination of copper etching and stencil printing nickel/silver conductive ink thermocouple materials onto a thin-film polyimide Kapton® substrate. The semi-automated production capabilities of this manufacturing process significantly decrease the cost of producing thin-film heat flux sensors while still maintaining acceptable performance characteristics. Material testing was performed to first determine the most appropriate materials as well as the theoretical sensitivity and time response of the final sensor. Seebeck coefficient of a thermocouple formed using the combination of EMS CI-1001 silver and EMS CI-5001 nickel ink was measured to be 18.3 ± 0.9 uV/ deg C. Calibrations were then performed on a sample of sensors produced using the novel manufacturing process to verify theoretical values for both sensitivity and time response. The printed heat flux sensor (PHFS) made using this process has a nominal voltage output sensitivity of 4.10 ± 0.23 mV/(W/cm2) and first order time constant response time of 0.592 ± 0.026 seconds. Lastly, a cost analysis was performed to estimate that the final cost to produce the PHFS is approximately $7.73 per sensor. This cost is significantly lower than commercially available sensors which range from $210 upwards to $3000. / Master of Science

Development of a Direct-Measurement Thin-Film Heat Flux Array

Ewing, Jerrod Albert 16 January 2007 (has links)
A new thin film heat flux array (HFA) was designed and constructed using a series of nickel/copper thermocouples deposited onto a thin Kapton® polyimide film. The HFA is capable of withstanding temperatures up to 300 °C and produces signals of 42 μV/(W/cm²). As a result of its thin film construction, the HFA has a first order time constant of 32 ms. Calibrations were completed to determine the gage's output as well as its time response. In order to measure the signal from the HFA amplifiers were designed to increase the magnitude of the voltage output. An example case is given where the HFA is used in an experiment to correlate time-resolved heat flux and velocities. / Master of Science

Direct Measurement of Boiling Water Heat Flux for Predicting and Controlling Near Critical Heat Flux

Thompson, Jordan Lee 23 May 2013 (has links)
A novel method for measuring heat flux of boiling water is designed and built to study critical heat flux (CHF) and observe the response of a heat flux sensor when CHF occurs. A high temperature heat flux sensor is embedded in the wall of a pipe to get a direct measurement of the surface heat flux and sensor temperature. By submerging the pipe in water and applying a controlled heat flux to the inside diameter over the area where the sensor is located, boiling is created on the outer surface while measuring the heat flux. The heat flux is gradually increased up to CHF and the heat flux response is observed to determine if the heat flux sensor could sense CHF when it occurred. The heat flux sensor is able to consistently measure the value for CHF, which is approximately 510 kW/m" for this system. It is also observed during the experiments that the heat flux response undergoes an inflection of the heat transfer coefficient at a consistent temperature just before reaching CHF. This observed inflection caused the heat flux response to deviate from its cubic relationship with the temperature and drastically increase for a very small change in temperature. This inflection response can be used as an indication for approaching CHF and can also be used to approximate its value without prior knowledge of when it occurs. / Master of Science

The development of robust heat transfer instrumentation for rotating turbomachinery

Greenwood, Joanne R. January 2000 (has links)
No description available.

Linearised perturbations of two-dimensional Stefan problems in spherical, cylindrical and planar geometries

Gammon, Jael January 1995 (has links)
No description available.

Clean heat flux sensor for ash fouling monitoring

Hu, ZhengYu 03 September 2009 (has links)
An ash monitoring system prototype that consists of a “clean” heat flux sensor and a “dirty” heat flux sensor was developed in this study. The “clean” heat flux sensor was studied numerically and experimentally while the “dirty” heat flux sensor was tested in the experiment. Two different measurement methods were applied on the “clean” sensor, one from the original study and one proposed in the present work. The new method required additional data processing procedures to be able to work in an on-line basis. Among the three data processing procedures developed in this study the central temperature difference procedure was found to be the most reliable one. Numerical results provided valuable information about the heat transfer pattern at the sensing element and also the performance of the sensor at high radiation heat flux levels. A rough calibration of both “clean” and “dirty” heat flux sensors was conducted experimentally. Nevertheless, the experimental results still served as a primary assessment for both sensors. Observed disagreements between the original study and the present one were probably caused by the modification of the sensor structure made in the present study. Sensitivity variation at high heat flux levels did not appear in the numerical results of either measurement method. Low overall sensor temperature change was believed to be the main reason as it meant less change in thermal properties of the sensing disc. Although the results of the study suggested that the proposed oscillation method was less attractive than the original one, it increased the possibility of resolving the surface characteristic variation problem that was considered crucial for the performances of the “clean” heat flux sensor regardless of the measurement method used. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-09-03 16:38:26.48

The simultaneous measurement of time-resolved surface heat flux and freestream turbulence at a stagnation point /

Simmons, Stephen Gordon, January 1990 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 88-91). Also available via the Internet.

Investigation into the pool-boiling characteristics of gold nanofluids

Jackson, Jenny E. January 2007 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 4, 2008) Includes bibliographical references.

Characterization and quantification of ground heat flux for late season shallow snow

LaMontagne, Aurele. January 2009 (has links)
Thesis (M.S.)--Boise State University, 2009. / Title from t.p. of PDF file (viewed April 9, 2010). Includes abstract. Includes bibliographical references (leaves 66-69).

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